Aziridine ring opening for the synthesis of sphingolipid analogues: Inhibitors of sphingolipid-metabolizing enzymes

Article

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Aziridine Ring Opening for the Synthesis of Sphingolipid Analogues:

Inhibitors of Sphingolipid-Metabolizing Enzymes

Anna Alcaide and Amadeu Llebaria*

̀

Medicinal Chemistry Laboratory (MedChemLab), Departament de Química Biomedica, Institut de Química Avanca̧ da de Catalunya

(IQAC−CSIC), Jordi Girona 18-26, Barcelona 08034, Spain

S

* Supporting Information

ABSTRACT: A library of sphingolipid analogues is designed and tested as inhibi-

tors against mammalian and fungal sphingolipid enzymes. The synthesis of sphin-

golipid analogues is based on the nucleophilic ring-opening reactions of N-activated

aziridine derivatives with thiols, β-thioglycosyl thiols, phosphorothioates, phosphates,

and amines to aﬀord compounds having diﬀerent lipid backbones and substituents

representative of the naturally occurring sphingolipid families. The screening on

mammalian sphingomyelin synthase (SMS) and glucosylceramide synthase (GCS)

and yeast inositol phosphorylceramide synthase (IPCS) enzymes identiﬁed several

inhibitors of GCS and IPCS, but no inhibition of SMS was observed among the

tested compounds.

On the other hand, sphingolipid synthesis is vital for the growth

and viability of fungi or plants, and for that reason, the inhibition

of the essential enzyme inositol phosphorylceramide synthase

(IPCS) and in turn the synthesis of sphingolipids is considered

an eﬃcient and selective strategy to ﬁnd antifungal drugs.^12,13

Due to the important biological roles of sphingolipids, the

development of chemical inhibitors of sphingolipid enzymes is a

subject of interest.¹⁴⁻¹⁷A large number of sphingolipid ana-

logues have been synthesized by the introduction of diﬀerent

chemical modiﬁcations in the natural (phyto)sphingosine back-

bone to search for molecules capable of modulating the biological

activity of the original compound.^14,16−19

In this context, we were interested in a modular and practical

methodology for the synthesis of sphingolipid analogues and its

use to obtain libraries of compounds modiﬁed at the backbones,

the N-acyl or other amino substituents group, or the substituent

at C1. Accordingly, we developed key aziridine derivatives^20,21

for the synthesis of diﬀerent series of analogues, such as

ceramides, phytoceramides, sphingosines, and dihydrocera-

mides, that were tested for activity in enzymes involved in

sphingolipid metabolism.

INTRODUCTION

■

Sphingolipids are essential structural components of eukaryotic

membranes with amphipathic character that tend to aggregate

into membranous structures, where they are mostly present in the

plasma membrane and related cell membranes, such as Golgi

membranes and lysosomes. In addition to the structural role these

lipids are also bioactive signaling molecules that have crucial functions

in diﬀerent cellular processes and physiological cell function.^1,2

Sphingolipids are deﬁned by their long carbon backbones with

a 2-amino-1,3-diol functionality (usually 2S,3R) that can be

distinguished by chain length, number of insaturations, and the

presence of additional hydroxyl groups in their general structure.

These organic compounds are called sphingoid bases and can be

N-acylated by fatty acids giving ceramides. Modiﬁcations of this

general structure give diverse families of sphingolipids depending

on a variety of charged, neutral, phosphorylated, and/or glyco-

sylated moieties attached at position 1 (Chart 1).^3,4

The anomalous metabolism or expression of speciﬁc sphin-

golipids or glycosphingolipids is related to diseases such as can-

cer,⁵Alzheimer’s disease,⁶or sphingolipidoses and therefore can

be potentially treated or prevented through pharmacological

intervention on sphingolipid metabolism and the interaction

with these lipid cellular targets.

In recent years, sphingomyelin synthase (SMS) has been

considered a potential drug target, because it plays an important

role in cell survival and apoptosis, inﬂammation, and lipid ho-

meostasis.⁷Glucosylceramide synthase (GCS) is also considered

a target for combating human pathologies⁸due to excessive

lysosomal glycosphingolipid storage. Some associated pathologies

are the Gaucher,⁹Fabry,¹⁰Tay-Sachs, and Sandhoﬀ dis-

eases,¹¹which originate from accumulation of glucosylceramide or

other glycosphingolipids due to their deﬁcient degradation in the cell.

When comparing this strategy with previous method-

ologies,^22,23the main advantage is a high versatility, allowing

the synthesis of diﬀerent structural analogues from common

aziridine precursors that can be prepared on a multigram scale

from commercially available starting materials. In this manner,

by simply changing the nucleophile in the aziridine ring-opening

reaction step or the N-activating group of the aziridine a variety of

compounds can be obtained.

Received: January 10, 2014

Published: March 5, 2014

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Chart 1. Chemical Structures of Naturally Occuring Sphingolipids

Figure 1. Sphingolipid analogues by ring-opening reactions of aziridines.

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Scheme 1. Obtention of Aziridines 1 and 2 from Commercial Phytosphingosine Hydrochloride 3 and Reported Methodology To

Obtain 1-Thiophytosphingolipid Analogues^20,21

The N-acylation of these aziridines would lead directly to the

preparation of ceramides, whereas other N-activating groups can

give access to sphingosines, which in turn can also be acylated to

amides, giving an alternative way to obtain ceramides. Further-

more, the double bond present in the ceramide series can be

reduced to give the corresponding dihydroceramides. The

resulting sphingolipid analogue libraries are of interest for

structure−activity studies in biological targets (Figure 1).

The sphingosine aziridine 2 and its derivatives were pro-

posed for the synthesis of compounds having the mammalian

sphingolipid skeleton containing a double bond and also their

saturated derivatives. The obtention of aziridine 2 (Scheme 1)

was based on the work of Kim et al. that describes a method for

the preparation of sphingosine starting from commercial

phytosphingosine hydrochloride 3.²⁴We essentially followed

the reported sequence to synthesize azide 6 from compound 7,

which is a common intermediate in the synthesis of aziridines 1

and 2. Diol 7 was treated with thionyl chloride in the presence of

TEA in CH₂Cl₂to give a mixture of sulfur diastereomers 8, which

converged to a single cyclic sulfate 9 after oxidation. Ring-

opening reaction of sulfate 9 with tetrabutylammonium iodide

(TBAI) and subsequent elimination reaction with DBU in re-

ﬂuxing toluene gave the desired alcohol 6 after pTSA·H₂O-

catalyzed hydrolysis²⁵of the sulfate monoester 10. The protection of

the hydroxyl functional group of 6 as methoxy-

methyl ether gave intermediate 11, which was followed by cleavage

of the primary alcohol protecting group to azidoalcohol 12. This was

transformed to mesylate 13 and aﬀorded aziridine 2 after Staudinger

reduction with simultaneous intramolecular cyclization.

RESULTS AND DISCUSSION

■

Aziridine Precursors to Synthesize (Phyto)sphingosine

Analogues. The synthesis of the analogues was based on the

ring-opening reaction of N-activated aziridine derivatives 1 and 2

(Scheme 1), which was predicted to give the desired (phyto)-

sphingolipid analogues with chemical diversity. Aziridine 1^20,21

was obtained from comercial phytosphingosine hydrochloride

3 as previously described.^20,21This compound was envisaged

as a key intermediate for the synthesis of phytosphingolipid

analogues. The usefulness of 1 was eﬀectively conﬁrmed for the

synthesis of 1-thiophytosphingolipid analogues by microwave-

promoted nucleophilic ring-opening reactions of the acylated

aziridines 4²¹and 5²¹with thiols²¹producing a variety of

1-thiosphingolipids (Scheme 1).

Activation of Aziridines for Ring-Opening Reactions To

Obtain Sphingolipid Analogues. Literature references^26,27

related to aziridine reactivity for the nucleophilic ring-opening

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reactions report that free aziridines need to be activated to

increase the electrophilicity of these chemical species. Since in

our case most of the desired modiﬁcations in the sphingolipid

framework contain N-acyl groups, it was considered that

N-acylaziridines would be an optimal solution because this

would directly lead to ceramides, avoiding the formation and

cleavage steps of other groups and increasing the synthetic

eﬃciency. Moreover, we thought that this approach could be

expanded to the synthesis of lysosphingolipid derivatives having

a free amino group if a benzyl carbamate was used in the aziridine

intermediate as amino activating group (Scheme 1).^20,21

Sometimes N-acylaziridines are not as reactive as required for

nucleophilic opening, and other nitrogen activating groups of

general application were also considered to increase the reactivity

of these derivatives for nucleophilic opening reactions at the expense

of requiring further nitrogen deprotection and acylation steps.

It is well-known that N-arylsulfonylaziridines are highly

activated for ring-opening reactions with nucleophiles,²⁸⁻³⁰but

the cleavage of the resulting sulfonamides is usually diﬃcult and

the usually required drastic conditions are uncompatible with

several functionalities. This has been addressed using other

deprotection alternatives³¹⁻³⁵and a generation of sulfonyl

groups.³⁶⁻³⁹One of these groups, 2-naphthalenesulfonamide,⁴⁰

which combines the eﬃcient activation with milder deprotection

conditions, was selected when N-acylaziridines were not active

enough to carry out the desired ring-opening reactions.

Scheme 2. Obtention of N-Functionalized Aziridines: (a)

Aziridine 1 Derivatives and (b) Aziridine 2 Derivatives

In order to test the nucleophilic ring-opening reactions toward

sphingolipid analogues, a variety of N-functionalized derivatives

were obtained from aziridines 1 and 2 (Schemes 1 and 2). When

aziridine 1^20,21was reacted with octanoyl chloride, benzylchlor-

oformate or (Z)-tetracos-15-enoyl chloride, aziridines 4,²¹5,²¹

and 14, respectively, were obtained (Scheme 2a). Analogously,

the reaction with naphthalene-2-sulfonyl chloride gave the

corresponding N-sulfonylaziridine 15 (Scheme 2a). Similarly,

N-acylaziridines 16 and 17 were prepared from sphingosine

aziridine 2 in high yields by reaction with capryloyl chloride or

(Z)-tetracos-15-enoyl chloride, respectively (Scheme 2b).

In the present publication, the N-activated aziridine derivatives

4, 5, and 14−17 were subjected to ring-opening reactions with

diﬀerent nucleophiles to obtain a variety of sphingolipid ana-

logues by a short and ﬂexible route.

Reactivity of Aziridines with Thiols To Obtain 1-Thio-

(phyto)sphingosine Analogues. Although a variety of

chemical modiﬁcations at position 1 of phytosphingosine have

been published in the literature,^20,41no precedents of the syn-

thesis of 1-thio-(phyto)sphingosine analogues were found, with

the exception of 1-thioglycolipid analogues, which have been

studied for their eﬀect on NKT cell activation.^42,43

Usually aziridines and thiols react with attack of the nucle-

ophile at the aziridine less hindered site to provide 2-amino

thioether products.⁴⁴We have discovered²¹that MW activation

eﬀectively enhances the thiol reactivity with N-acylphytosphin-

gosine aziridines 4 and 5, which after diol deprotection gave

1-thio-phytosphingosine analogues.

At this stage, it was considered to extend these procedures to

the synthesis of 1-thio-sphingolipids with the introduction of

sphingosine base, longer N-acyl chains, and the use of more polar

and functionalized thiol nucleophiles attached at position 1 to

eﬀectively mimic several classes of bioactive sphingolipids. This

required testing the reactivity of N-acyl derivatives 14, 16, and

17 to prepare 1-thio-(phyto)sphingosine analogues. The same

reaction conditions (DBU, MeCN, and MW irradiation) pre-

viously described²¹were used for the synthesis of this group of

(phyto)sphingolipid analogues, requiring in any case irradiation

times longer than 1 h (Scheme 3, entries 1−6) to aﬀord adducts

18a−18f. The reaction yields in the ring-opening reaction of

14 with aromatic or heteroaromatic thiols, such as thiophenol

(Scheme 3, entry 1), 4-(4-bromophenyl)-2-thiazolethiol

(Scheme 3, entry 2), and 2-pyridinethiol (Scheme 3, entry 3),

were good. In addition, the isopropylidene acetal cleavage with

CSA also proceeded with high yields to obtain alcohols 19a−19c.

Sometimes the election of the solvent was very important for the

eﬀective deprotection of the diol functionalities and MeOH/

CHCl₃or MeOH/CH₂Cl₂mixtures and gentle heating to higher

reaction temperatures (30 °C) were needed to acetal cleavage.

In the sphingosine series (Scheme 3, entries 4−6), the allylic

alcohol deprotection of adducts 18d−18f with catalytic aq HCl

in MeOH at 64 °C⁴⁵gave ceramide analogues 19d−19f.

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Scheme 3. Ring-Opening Reaction of N-Acylaziridines with Thiols under Microwave Irradiation and Functional Groups

Deprotection

In summary, the use of MW irradiation in the reaction of thiols

and N-acylaziridines followed by alcohol deprotection results in an

eﬃcient way of producing a variety of 1-thiosphingolipid analogues.

Reactivity of Aziridines with β-Thioglycosyl Thiols To

Obtain 1-Thio-β-glycolipid Analogues. Thioglycosidic

analogues of sphingolipids are an interesting class of compounds

due to the important biological functions of glycosphingoli-

pids^46,47and the metabolic stability of thioglycosides to enzy-

matic cleavage.⁴⁸

Glycosphingolipids having a phytoceramide scaﬀold have been

the object of attention since the discovery of their immunosti-

mulant activity.⁴⁹Particularly α-galactosylceramides, such as

the natural agelasphins⁵⁰or the synthetic KRN7000,⁴³other

synthetic thioglycoside analogues,^42,43,51and aminocyclitol-

substituted phytoceramides^52,53have been studied for their

eﬀect on NKT cell activation.

1-thio-glycosphingolipid analogues. As a starting point for the

obtention of the compounds of interest, commercially available

1-thio-β-^D-glucose tetraacetate (20) was chosen to test the

applicability of this particular class of thiols in the reaction with

N-acylaziridines.

When aziridine 4 (1.0 molar equiv) was reacted with thiol 20

(1.2 molar equiv) under MW irradiation at 100 °C in the pre-

sence of DBU (1.1 molar equiv) in MeCN, we observed total

consumption of the thiosugar with recovery of unaﬀected

aziridine 4. Diﬀerent reaction modiﬁcations (see Supporting

Information for additional data) involving the nature or

stoichiometry of the base, temperature, solvent, and other

reaction parameters were attempted to optimize the formation of

β-adduct 21 (Scheme 4).

Under the less unfavorable conditions, the reaction of aziridine

4 (1.0 molar equiv) and 1-thio-β-^D-glucose tetraacetate (20) (1.2

molar equiv) was possible under microwave irradiation at 40 °C,

with DBU (1.1 molar equiv) in MeCN (Scheme 4). However the

We were interested in testing thioglycosides as nucleophiles

in sphingolipid aziridine opening, which would lead to

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Scheme 4. Ring-Opening Reaction of Aziridine 4 with 1-Thio-β-D-glucose Tetraacetate (20) and Cleavage of Protecting Groups

desired product 21 was obtained in only 26% yield, which was

accompanied by the α-anomer 22 isolated in 19% yield. It

was clear that acetylated thiosugars needed a speciﬁc treatment in

the reaction, due to their low stability under the previously

developed conditions for aziridine opening with thiols. An

attractive alternative was the procedure reported by Zhu and

Schmidt to synthesize S-linked glycopeptides.⁵⁴Thus, aziridine

derivative 4 (1.0 molar equiv) was treated at pH 9 with thiosugar

20 (3 molar equiv added in 3 portions) in a biphasic system

formed by AcOEt and 1 M aq NaHCO₃in the presence of tetra-

n-butylammonium hydrogensulfate (TBAHS) (4.0 molar equiv)

under microwave irradiation at 40 °C. Under these conditions,

the thioglycosphingolipid 21 was obtained in a moderate 53%

yield with no traces of the α-anomer 22 (Scheme 4).

The hydrolysis of the isopropylidene group in 21 was carried

out in the presence of CSA in methanol giving a mixture of

products, which appeared to be originated from migration of

acetate groups. Treatment of this mixture with Ac₂O in pyridine

conﬁrmed our hypothesis because the mixture of products con-

verged to a single peracetylated derivative 23. Finally, Zemplen

deacylation⁵⁵reaction of 23 with NaOMe/MeOH gave the

ﬁnal β-thio-phytosphingolipid analogue 24 in moderate yield.

Although this method was suitable for the preparation of the 1-S-

glucosylthioceramides, we decided to explore an alternative to

the N-acyl to increase aziridine reactivity. For that reason,

aziridine 1 was functionalized to 2-naphthalenesulfonamide,

which can be cleaved under milder reaction conditions than

benzenesulfonamides.⁴⁰Aziridine derivative 15 was synthesized

as has been previously described (Scheme 2a) by reaction of

1 with 2-naphthalenesulfonyl chloride.

yield, showing a slight improvement versus yields obtained with

N-acylaziridines under MW conditions. The preparation of the

ﬁnal thiosphingolipid analogues from 25a,25b adducts required

hydroxyl deprotection, removal of the napthalenesulfonyl group,

and N-acylation when phytoceramide derivatives were desired.

Acetal deprotection reaction of 25a was performed with CSA in

MeOH, and diol 26 was isolated in high yield. However, all

attempts for sulfonylamide cleavage in 26 under the reported

conditions (Mg, NH₄Cl/MeOH)⁴⁰to give the corresponding

amine were unsuccessful and unidentiﬁed mixtures of products

were obtained.

We next tried to obtain the corresponding 1-S-glucophytos-

phingosine from sulfonamide 25b. Acetal cleavage in 25b gave a

mixture of products that was acetylated and converged to a single

hexaacetate 27, which could be puriﬁed and isolated in high yield.

The synthesis of the desired ﬁnal product required both acetate

and sulfonamide cleavage, but this proved a diﬃcult task. The

acetate hydrolysis with aq NH₃produced alcohol 28, but the

cleavage of the sulfonamide to aminoalcohol 29 proved again

unsuccessful, giving intractable mixtures of products. In addition,

the diol deprotection of adduct 25b and the subsequent deac-

etylation in the presence of NaOMe/MeOH aﬀorded compound

28 in moderate yield from 25b. However, when the sulfonyl

group cleavage was ﬁrst attempted in 27, a mixture of products

was obtained that was treated with aq NH₃in MeOH to give

acetamide 30 in 18% yield.

Overall, the N-sulfonylaziridine approach showed a higher

reactivity in the opening reaction step, and it is clearly suitable for

the preparation of N-sulfonyl analogues, but the strenuous

diﬃculties in the sulfonamide cleavage precluded N-sulfonylazir-

idine use for the synthesis of thio-β-glycolipid phytoceramides.

At this point, we concluded that the previous biphasic con-

ditions under MW irradiation were the more practical and direct

methodology to prepare this kind of products for biological

testing at milligram scale.

The reactivity of 15 was ﬁrst studied with thiophenol. As it was

expected, total consumption of the starting aziridine 15 was

observed by TLC after 12 h of reaction at room temperature, and

ring-opened product 25a was isolated in 96% yield (Scheme 5).

Under these conditions, the reaction of sulfonylaziridine 15 with

1-thio-β-^D-glucose tetraacetate (20) gave product 25b in 63%

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Scheme 5. Ring-Opening Reactions of Aziridine Derivative 15 and Deprotection Reactions of Adducts

Thus, long-chain aziridine derivative 14 was reacted with

commercial thioglucose 20 under the same reaction conditions

already described to aﬀord thioglycoside analogues (Scheme 6).

In this case, the yield in the ring-opening reaction step was low,

allowing the obtention of adduct 31 in 26% (65% conversion)

yield. It was clear that the presence of a long chain N-acyl sub-

stituent in 14 was detrimental for the reactivity of the aziridine.

After acetal cleavage and O-acetyl removal the ﬁnal thioglycoside

analogue 32 was obtained in 62% yield from 31.

Adduct 35 was treated in acidic methanol to cleave the

methoxymethyl ether protecting group and aﬀord a complex

mixture of products that converged to intermediate 36 after

reacylation reaction. The unoptimized deprotection procedure

gave a very low yield of 36 due to the formation of diﬀerent

reaction byproducts under these strong acidic conditions. Finally,

treatment of peracetate 36 with NaOMe/MeOH gave us the

glycolipid 37 with purity suitable for future biological testing

(>90% HPLC) in quantitative yield.

In a slightly modiﬁed procedure, the reaction of derivative 14

with the O-deacetylated sugar 33 to aﬀord the partially protected

intermediate 34 and then product 32 after cleavage of the iso-

propylidene acetal was attempted without success (Scheme 6).⁵⁶

To test the feasibility of the sphingosine 1-thioglycolipids

synthesis, we tested the reaction of aziridine derivative 17 with

thioglucose 20. Again, the use of MW irradiation at 40 °C, in the

presence of DBU in MeCN or the use of LiClO₄⁵⁷as additive was

not successful (see Supporting Information for additional data).

However, the biphasic reaction conditions (AcOEt/1 M aq

NaHCO₃, MW) yielded the thioglycolipid 35 in 42% yield

(Scheme 7).

It was concluded that the synthetic methodology to obtain 1-

thio-β-glycosyl analogues resulted in low to moderate yield but

was practical for the preparation of thioglycoside analogues from

O-acetylated glycosyl thiols in amounts amenable for biological

assays.

Reactivity of Aziridines with Phosphorothioates and

Phosphates to Obtain Phyto-sphingosine Analogues.

Phosphosphingolipids are important bioactive lipids that can

modulate physiological processes. For example, ^D-erythro-

sphingosine-1-phosphate⁵⁸and ceramide 1-phosphate⁵⁹

have important roles in cell signaling cascades,⁶⁰and

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the reaction in CH₂Cl₂at room temperature showed very low

reactivity. It was necessary to use 1,2-dichloroethane as a solvent

and to heat to 75 °C for 3 days to observe total consumption of

the starting aziridine (Scheme 8). After ﬂash chromatography,

the expected product 40 was isolated in 26% yield accompanied

of a 1:1 mixture of compounds 41 and 42. The S-benzyl

compound 41, which has been previously described in the

literature,⁷¹was presumably formed from the attack of 38 on a

phosphate benzyl group, whereas the S-chloroethyl derivative 42

was probably formed by the attack of phosphorothioate 38 to

1,2-dichloroethane. The formation of 41 and 42 reﬂects a low

reactivity of the aziridine with the phosphorothioate nucleophile

that competes with S-alkylation reactions with benzyl phosphates

or the solvent, respectively.

Scheme 6. Synthetic Route for the Obtention of

Thioglycoside Phytoceramide Derivatives

We next attempted the reaction under acidic media using O,O-

dibenzyl S-hydrogen phosphorothioate 43 and aziridine 4 in

THF at 75 °C, obtaining adduct 40 in 27% yield, which was

accompanied by a similar amount of S-benzyl derivative 41.

Then, the option of changing the phosphorothioate salt 38 for an

alternative phosphorothioate lacking electrophilic benzyl groups,

such as triethylammonium O,O-dimethyl phosphorothioate (44)

(Scheme 9), was considered to avoid the formation of S-benzyl

derivatives.

Phosphorothioate 44 was prepared from 45, and the reaction

with aziridine derivative 4 in THF at 75 °C for 3 days gave the

desired ring-opened product 46a in 21% yield, but no other

reaction byproducts were detected. However, the reaction yield

was increased to 67% when O,O-dimethyl S-hydrogenphosphor-

othioate (47) was reacted with aziridine derivative 4. After that,

acetal deprotection aﬀorded diol 48 in 63% yield, and subsequent

cleavage of the dimethylphosphodiester group with bromo-

trimethylsilane led to an unseparable 1:2 mixture of the cor-

responding monomethylphosphate intermediate and the

ammonium salt 49 in a single attempt (Scheme 9). No attempts

to optimize this reaction were made. Under similar conditions,

aziridine 5 (1.0 molar equiv) was reacted with compound 47

(2.6 molar equiv), and adduct 46b was isolated in 49% yield

(Scheme 9).

The synthesis of O-phosphorylated analogues based on

aziridine opening is also attractive, due to their important bio-

logical properties and the limited number of methods to prepare

these compounds. Literature references report the synthesis of

analogues of sphingosine-1-phosphate,^16,72ceramide-1-phos-

phate,^73,74D-ribo-phytosphigosine-1-phoshate,^65,75or L-lyxo-

phytosphigosine-1-phoshate.⁷⁶

D-ribo-phytosphingosine-1-phosphate mediates cellular pro-

cesses with a signaling role in yeast.⁶¹

Furthermore, the synthesis of sphingomyelin sulfur ana-

logues⁶²modiﬁed on the oxygen connecting the phosphocholine

group to the ceramide backbone to study their molecular

properties⁶³and interactions with cholesterol or their behavior

toward sphingomyelinase⁶⁴has been described.

In accordance to the precedents of ring-opening reactions of

N-acylaziridines with dibenzylphosphoric acid,^77,78aziridine 4

(1.0 molar equiv) was treated with phosphodiester 50 (1.3 molar

equiv) in CH₂Cl₂at room temperature (Scheme 10) to give

compound 51a in a satisfactory 63% yield after 3 days. Heating at

reﬂux to enhance the reactivity gave a mixture of 50% phosphate

51a and 24% alcohol 52. Stepwise deprotection of adduct 51a

involving acetal cleavage with CSA in MeOH to give diol 53a

followed by Pd/C-catalyzed hydrogenolysis aﬀorded the desired

ﬁnal phytoceramide phosphate 54a (Scheme 10). This sequence

was also applied to aziridine derivative 5 to obtain the sphin-

gosine analogue 54b. However, the lower reactivity of aziridine 5

with dibenzylphosphate precluded the ring-opening reaction in

CH₂Cl₂at room temperature, and it was necessary to increase the

reaction temperature to 75 °C in 1,2-dichloroethane as a solvent

for 48 h to give the phosphorylated adduct 51b in 72% yield. This

was followed by the acetal deprotection to 53b and O-benzyl

hydrogenolysis to give ﬁnal phytosphingosine-1-phosphate 54b.

From the synthetic point of view, the phosphosphingolipids

are usually obtained by direct phosphorylation of the alcohol

function of ceramides in the presence of a variety of phos-

phorylating agents.⁶⁵⁻⁶⁸Alternatively, we were interested in the

possible use of aziridine derivatives in the synthesis of

phosphorylated sphingolipid compounds.

On the basis of the synthesis of 1-thio-(phyto)sphingosine

analogues, we were interested in the preparation of 1-thio-

phosphosphingolipid analogues. For that reason, we attempted

the use of S-phosphorothioates⁶⁹as nucleophiles in the ring-

opening aziridine reactions. We started synthesizing the known

triethylammonium O,O-dibenzyl phosphorothioate 38⁷⁰by oxi-

dation of commercial dibenzylphosphite 39 with sulfur in the

presence of TEA in a 1:1 mixture of Et₂O/AcOEt (Scheme 8).⁷⁰

With phosphorothioate 38 in hand, we studied the reaction

with aziridine derivative 4. The attempts to use similar reaction

conditions (DBU, MeCN, and MW irradiation) as those pre-

viously described²¹for thiols led to inconclusive results, whereas

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Scheme 7. Synthetic Route To Obtain Thioglycoside Sphingosine Analogues

Scheme 8. Ring-Opening of Aziridine 4 with Phosphorothioates 38 and 43 To Obtain Adduct 40

In summary, the ring-opening reactions of functionalized

aziridines with phosphoric acid derivatives can be applied to the

synthesis of 1-phosphorylated derivatives of sphingosine and

ceramide. This is an interesting and experimentally simple

alternative to the usual alcohol phosphorylation methodologies.

Reactivity of Aziridines with Amines To Obtain 1-

Amino-(phyto)ceramide Analogues. Literature precedents

report that natural or synthetic compounds incorporating the 1,2-

diamino functionality have been the object of considerable attention

because of their valuable biological and therapeutic properties.⁷⁹⁻⁸¹

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Literature reports for nucleophilic ring-opening reactions of

aziridines with amines to obtain 1-amino-(phyto)sphingolipid

analogues are known for phytosphingosine-derived N-nosylazir-

idines,^20,53and the ring-opening reaction of 2,4-dinitrophenyl⁸⁴

aziridines to synthesize ceramide analogues is also reported.

However, no reports were found for opening reactions of N-

acylaziridines with amines to aﬀord the compounds of interest.

First attempts to react aziridine derivative 4 and n-heptylamine

in MeCN at room temperature were based on previously

described methodology to obtain 1,2-diaminophytosphingoli-

pids,²⁰but this procedure did not aﬀord the expected ring-

opened product 55a (Scheme 11) even after long reaction times

(up to 4 days). Increasing the reaction temperature to 80 °C and

heating overnight, the use of MW irradiation,^90,91or the addition

of promoting agents such as tributylphosphine⁹²were also un-

successful. Gratifyingly, the use of LiClO₄in MeCN under

thermal conditions at 80 °C overnight, according to the pro-

cedure reported by Crotti et al.,⁵⁷gave us the desired ring-

opened product 55a in 93% yield (Scheme 11, entry 1). The

LiClO₄reaction conditions were extended to a variety of amines

including primary and secondary amines, cyclic amines, amines

with aromatic substituents, and several functionalized amines to

synthesize structurally diverse 1-amino-sphingolipid analogues

(Scheme 11). In this way, amino-phytoceramide adducts 55a−

55i (Scheme 11, entries 1−9) were obtained from phytosphin-

gosine aziridine derivatives 4 or 14, and 1-amino-ceramides 55j−

55m (Scheme 11, entries 10−13) starting from N-acylaziridine

sphingosine derivative 16 (Scheme 11).

In general, reactions of aziridine derivatives with alkylamines

such as n-heptylamine (Scheme 11, entry 1) and dibutylamine

(Scheme 11, entry 3) or cyclic amines such as pyrrolidine

(Scheme 11, entries 4 and 10), morpholine (Scheme 11, entries

5, 8, and 11), or 1-methylpiperazine (Scheme 11, entry 9) gave

higher yields than reactions with functionalized secondary

alkylamines (Scheme 11, entries 6, 7, 12 and 13). When di-

ethanolamine (Scheme 11, entry 6) was reacted with aziridine 4,

adduct 55f was obtained in high yield, but the yield was lower

when benzylethanolamine (Scheme 11, entry 7) was used as

nucleophile to give adduct 55g. Reactions between aziridine 16

and amines gave in general slightly lower yields than with phy-

tosphingosine aziridine 4. Thus, when pyrrolidine (Scheme 11,

Scheme 9. Ring-Opening Reaction of Aziridines with

Nucleophiles 44 and 47 and Adduct Deprotection Reactions

In particular, a variety of bioactive 1,2-diamino-(phyto)-

sphingolipid analogues have been synthesized by means of re-

placing the primary hydroxyl group present in natural (phyto)-

sphingosine with an amino group,⁸²a variety of amines,^20,83or

aminocyclitols.^53,84

In addition, this kind of lipid analogues can display a broad

spectrum of biological activity.^52,85,86Particularly, morpholino-

and pyrrolidinosphingolipids have been the object of attention,

because they are chemical analogues of 1R-phenyl-2R-

decanoylamino-3-morpholino-1-propanol ^D-threo (PDMP),⁸⁷

a

competitive inhibitor of glucosylceramide synthase.^83,88,89

For the reasons outlined above, it was considered that the

synthesis of 1-amino-(phyto)ceramide analogues by regioselec-

tive ring-opening reactions of N-acylaziridines with amines

would be of valuable interest to study them in diﬀerent biological

systems.

Scheme 10. Ring-Opening Reaction of N-Acylaziridines 4 and 5 with Dibenzylphosphate and Cleavage of Protecting Groups To

Aﬀord 1-Phospho-phytosphingolipids

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Scheme 11. Ring-Opening of N-Acylaziridines 4, 14, and 16 with Amines To Obtain 1-Amino(phyto)ceramides

entry 10) and morpholine (Scheme 11, entry 11) were used as

nucleophiles with aziridine 16, ring-opened products 55j and

55k, were obtained in 78% and 75% yield, respectively. When

using diethanolamine (Scheme 11, entry 12) and benzylethanol-

amine (Scheme 11, entry 13) as nucleophiles, the corresponding

adducts 55l and 55m were obtained in moderate yields. The

cleavage of the alcohol protecting groups in acidic methanol with

CSA when having phytoceramide adducts 55a−55i, or in the

presence of 37% aq HCl when reacting ring-opened products

55j−55m, aﬀorded the desired ﬁnal phytoceramide analogues

56a−56i and ceramide analogues 56j−56m in moderate to high

yields.

With these analogues in hand, we decided to go further and

test the reduction of the C4−C5 double bond present in the

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acylated sphingosine analogues 56j−56k to aﬀord the

corresponding dihydroceramide analogues (Scheme 12).

The interest in these compounds is based on the reports that

describe that some dihydroceramide analogues’ bioactive

conducting in vitro enzymatic assays with A549 cell homogenates

and ﬂuorescent substrate N-[6-[(7-nitro-2-1,3-benzoxadiazol-4-

yl)amino]hexanoyl]-^D-erythro-sphingosine (Cer-C6-NBD) to

detect the enzymatic product sphingomyelin-C6-NBD by

HPLC equipped with a ﬂuorescence detector. The measurement

of peak areas corresponding to sphingomyelin-C6-NBD gave a

measure of the extent of the reaction catalyzed by SMS.

In analogy with the experiments to determine SMS inhibitory

activity, the activity of the lipid analogues as inhibitors of GCS

was determined by conducting a similar catalytic assay using Cer-

C6-NBD/BSA and UDP-glucose as substrates and measuring

the formation of glucosylceramide-C6-NBD from the GCS-

catalyzed reaction.

Scheme 12. Double Bond Reduction of Ceramide Analogues

56j and 56k To Aﬀord Their Corresponding

Dihydroceramides

To test the inhibitory activity against SMS and GCS, rep-

resentative molecules were selected to maximize the chemical

diversity among the diﬀerent series of compounds described in

the present publication and a previous communication,²¹where

the synthesis of analogues 58−64 is reported (Chart 2). Table 1

summarizes the results corresponding to SMS and GCS %

inhibition at 50 μM.

Unfortunately, no meaningful SMS inhibition was detected

from (phyto)sphingolipid analogue libraries independently of

the nature of the sphingoid base (phytosphingosine or sphin-

gosine), the acyl group, or the C1 substituent (thioether, amino,

phosphate, or phosphorothioate). In contrast, results referring to

GCS showed interesting inhibitory activity (Table 1).

The best GCS inhibitors of this series are compounds having

pyrrolidino (56d, 56j, 57j), morpholino (56e, 56k, 57k),

or diethanolamino (56f, 56l) groups attached at position 1

of the (phyto)sphingosine derivatives, showing better results

the pyrrolidino-type derivates followed by morpholino- and

diethanolamino-type derivatives (Table 1 and Figure 2). In

addition, it should be noted that phytosphingosine analogues

(56d, 56e, 56f) show higher inhibition than their corresponding

properties are diﬀerent from those of the unsaturated ceramide

derivatives.⁹³

Oleﬁn reduction was expected to proceed easily, but attempts

to hydrogenate the double bond of analogues 56j and 56k with

5% Pd/C in MeOH at room temperature, in direct analogy with a

reported procedure,⁹⁴were not successful. Pleasingly, when

other catalysts were attempted, we identiﬁed Rh/Al₂O₃as an ex-

cellent system to obtain the dihydroceramide 57j from ceramide

analogue 56j in 91% yield (Scheme 12). Similarly, dihydrocer-

amide analogue 57k was obtained in 86% yield from ceramide

56k.

Studies of the Analogues As Inhibitors of Mammalian

SMS and GCS. The in vitro studies of the analogues as chem-

ical inhibitors included sphingomyelin synthase (SMS) and

glucosylceramide synthase (GCS) enzymes. The biological

activity of lipid analogues as inhibitors of SMS was tested by

Chart 2. Chemical Structures of the (Phyto)sphingolipid Analogues Tested As Inhibitors of SMS, GCS, or IPCS

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Table 1. Inhibitory Activity Values of Some (Phyto)sphingolipid Analogues against SMS and GCS at 50 μM

% inhibition

entry

analogue

SMS

GCS

1

19a

19b

24

<5

10

<5

16

18

5

<5

18

9

2

3

4

26

5

28

<5

7

6

30

7

56a

56b

56c

56d

56e

56f

56g

56j

56k

56m

56l

57j

57k

59

8

9

<5

22

14

<5

12

<5

9

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

93

83

68

<5

85

56

27

52

60

11

<5

6

60

61

62

9

63

<5

10

64

phosphatidylinositol (PI) and Cer-C6-NBD as substrates in

Saccharomyces cerevisiae yeast homogenates. As positive control

we used the known IPCS inhibior Khafrefungin at 200 nM, which

is the concentration known to produce 50% inhibition of IPCS

activity.

The HPLC measurement of peak area corresponding to ino-

sitol phosphorylceramide-C6-NBD (IPC-C6-NBD) related to

the ﬂuorescent ceramide gave the measurement of the extent of

the reaction catalyzed by the IPCS enzyme.

Representative analogues were selected to maximize the

chemical diversity among the diﬀerent series of compounds and

test their inhibitory activity against IPCS. The chemical struc-

tures of the selected compounds are included in Chart 2, and

Table 2 shows the corresponding IPCS inhibitory activity of

sphingolipid analogues tested at 50 μM.

Figure 2. Inhibitory activity of some (phyto)sphingolipid analogues

against GCS at 50 μM.

In general, the IPCS inhibitory activity (%) of the sphingolipid

analogues tested at 50 μM is lower than the inhibitory activity for

GCS, and the most active compounds inhibit IPCS around 50%

(Table 2 and Figure 3).

The chemical structures of the best inhibitors also contain

pyrrolidino (56d), morpholino (56e), and diethanolamino (56f)

groups attached at position 1 of the phytosphingosine back-

bone, but other analogues with other groups such as 2-(hydro-

xymethyl)phenylthio (59), dibutylamino (56c), phosphates

(54a), or phosphorothioates (48) are also moderately active.

Whereas analogues 56d, 56e, and 56f inhibit both IPCS and

GCS, the 2-(hydroxymethyl)phenylthio analogue 59 and the

sphingosine analogues (56j, 56k, 56l) with common N-acyl

chains and group attached at position 1 (Figure 2).

Furthermore, it is observed that analogues 57j and 57k,

which are the dihydroceramide derivatives of compounds 56j

and 56k, respectively, are weaker inhibitors than their corre-

sponding unsaturated ceramides. According to these results, we

can conﬁrm that the double bond of sphingosine is important for

its activity, this eﬀect being more relevant for morpholino

derivatives.

Biological Studies of the Analogues as Inhibitors of

Yeast IPCS. The synthesized analogues were also tested as

chemical inhibitors using an in vitro enzymatic assay with

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Although the developed synthetic methodology to obtain 1-

thio-(phyto)sphingolipid analogues could not be fully success-

fully adapted to obtain 1-thio-β-glycolipid analogues by reaction

with 1-thio-β-^D-glucose tetraacetate (20) owing to the low

stability of the sugar thiol under the reaction conditions, alter-

native biphasic (AcOEt/1 M aq NaHCO₃) condition in the

presence of TBAHS under microwave irradiation led to the

desired thioglycoside analogues in low to moderate yields and

was suitable for the synthesis at scale for testing in biological

systems.

Table 2. Inhibitory Activity of Some (Phyto)sphingolipid

Analogues against IPCS at 50 μM

It has been demonstrated that the synthetic methodology

based on reacting aziridine derivatives with nucleophiles is also

feasible when using phosphorylated compounds, such as phos-

phorothioates or commercial dibenzylphosphate. This strategy is

a practical and useful way to obtain phosphosphingolipid ana-

logues and an alternative to the direct phosphorylation of the

alcohol function of lipid analogues.

In addition, a useful synthetic methodology has been devel-

oped to obtain 1-amino-(phyto)ceramide analogue libraries

in moderate to good yields, by LiClO₄-promoted opening of

N-acylaziridine derivatives with a variety of amines. Furthermore,

the catalytic hydrogenation of the ﬁnal ceramide analogues

allowed us to obtain the dihydroceramide analogues as well.

A representative collection of the compounds have been tested

as inhibitors of sphingolipid metabolism enzymes, such as

mammalian SMS and GCS and fungal IPCS. Some of these

compounds are good inhibitors of GCS, and none of them inhibit

SMS. The IPCS active 2-(hydroxymethyl)phenylthio 59 and

di-n-butilamino 56c derivatives that do not aﬀect mammalian

enzymes show potential for further studies as GCS-selective

IPCS inhibitors.

entry

analogue

% inhibition IPCS

1

28

16

53

58

<5

21

48

43

41

54

<5

35

<5

11

14

30

2

48

3

54a

56a

56b

56c

56d

56e

56f

58

4

5

6

7

8

9

10

11

12

13

14

15

59

60

61

62

63

EXPERIMENTAL SECTION

■

General Experimental Methods. All moisture-sensitive reactions

were carried out under nitrogen. All materials were obtained

commercially and used without further puriﬁcation. Solvents were

dried prior to use with alumina in a solvent puriﬁcation system or

distilled and dried by standard methods. Thin-layer chromatography

(TLC) was performed on silica gel (Alugram Sil G/UV), and ﬂash

chromatography was done using silica gel 60 (40−63 μm) or an

automated puriﬁcation system. Analytical samples were homogeneous

as conﬁrmed by TLC and aﬀorded spectroscopic results consistent with

the assigned structures. Chemical shifts are reported in δ (ppm) relative

to the singlet at δ = 7.26 ppm of CDCl₃, the multiplet at δ = 3.31 ppm of

methanol-d₄, the multiplet at δ = 2.05 ppm of acetone-d₆, and the singlet

at δ = 7.21 ppm of pyridine-d₅for ¹H NMR and to the center line of the

triplet at δ = 77.16 ppm of CDCl₃, the multiplet at δ = 49.0 ppm of

methanol-d₄, and the triplet at δ = 123.5 ppm of pyridine-d₅for ¹³C

NMR. In general, ¹H and ¹³C assignments were done by using

gDQCOSY, gHSQC, or gHMBC sequences. ¹H and ¹³C assignments in

1-thio-β-glycolipid analogues are numbered with prime digits when

referred to the sugar moiety, whereas ordinary numbering is maintained

for the lipid backbone. IR spectra were registered as ﬁlm and were

recorded with a FT-IR Spectometer. [α]_Dvalues are given in 10⁻¹deg

cm²g⁻¹and were measured with a polarimeter. HRMS were recorded in

a time of ﬂight (TOF) mass spectrometer with electrospray ionization

(ESI). Melting points were measured with a digital melting point

apparatus.

Figure 3. Inhibitory activity of some (phyto)sphingolipid analogues

against IPCS and GCS at 50 μM. Kha: Khafrefungin at 200 nm.

Analogues 54a and 48 were not tested against GCS.

di-n-butilamino derivative 56c are active against IPCS and are

selective for mammalian SMS and GCS, showing potential for

antifungal development.

Microwave Irradiation Experiments. Reactions under microwave

irradiation were carried out in a CEM Discover Focused Microwave

reactor. The instrument consists of a continuous focused microwave

power delivery system with operator-selectable power output from 0 to

300 W. Reactions were performed in 10-mL glass vessels sealed with a

septum. The temperature of the content of the vessel was monitored

using an IR sensor, and the indicated temperature corresponds to the

maximal temperature reached during each experiment. The contents of

CONCLUSION

■

In summary, a variety of 1-thio-(phyto)sphingolipid analogues

have been synthesized by using a previously reported synthetic

and practical methodology that consists in the regioselective

nucleophilic ring-opening reactions of activated aziridines

followed by deprotection of functional groups in moderate to

good yields.

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the vessels were stirred by means of a rotating magnetic plate located

below the ﬂoor of the microwave cavity and a Teﬂon-coated magnetic

stir bar in the vessel. The speciﬁed time corresponds to the total irra-

diation time. Eﬃcient cooling is accomplished by means of pressurized

air during the entire experiment. Temperature, pressure, and power

proﬁles were monitored using commercially available software provided

by the microwave manufacturer.

(S)-2-((4S,5R)-2,2-Dimethyl-5-tetradecyl-1,3-dioxolan-4-yl)-

1-(naphthalen-2-ylsulfonyl)aziridine (15).

Continuous Flow Hydrogenations. Continuous ﬂow hydro-

genation reactions were performed in a H-Cube Continuous-ﬂow Hy-

drogenation Reactor where a continuous ﬂow of substrate is combined

with hydrogen, generated in situ from the electrolysis of water. The

hydrogen/substrate mixture can be heated and pressurized up to 100 °C

and 100 bar, respectively. The mixture is then passed through a packed

catalyst cartridge (CatCart) where the reaction takes place, and the

product continuously elutes out of the CatCart and into a collection vial.

Within 5 min, product emerges for fast reduction and optimization.

Reductions varying in scale from 10 mg to 10 g can be performed on the

same compact reactor. Every aspect of the operation on the H-Cube is

controlled and monitored using a touch-screen panel.

(S)-2-((4S,5R)-2,2-Dimethyl-5-tetradecyl-1,3-dioxolan-4-yl)-

aziridine (1). Synthesized according to literature procedures.^20,21

(S)-2-((4S,5R)-2,2-Dimethyl-5-tetradecyl-1,3-dioxolan-4-yl)-

1-octanoylaziridine (4) and (S)-Benzyl 2-((4S,5R)-2,2-dimethyl-

5-tetradecyl-1,3-dioxolan-4-yl)aziridine-1-carboxylate (5). Syn-

thesized according to literature procedures.²¹

To a solution of (S)-2-((4S,5R)-2,2-dimethyl-5-tetradecyl-1,3-dioxolan-

4-yl)aziridine (1)^20,21(625.0 mg, 1.84 mmol) and naphthalene-2-

sulfonyl chloride (421.3 mg, 1.84 mmol) in dry DCM (28 mL) was

added triethylamine (280 μL, 2.01 mmol). The resulting mixture was

stirred at room temperature for 24 h and then was diluted with DCM

(50 mL) and water (50 mL). The aqueous layer was extracted with

DCM (3 × 50 mL), the collected organic layers were dried over Na₂SO₄

and ﬁltered, and the solvent was removed under reduced pressure. Then,

the residue was puriﬁed by ﬂash chromatography (silica gel, hexane/

ethyl acetate 9.3:0.7) to give aziridine derivative 15 as a white solid

(843 mg, 86%). [α]²⁰_D−22.1 (c 1.12, CHCl₃). IR (ﬁlm): ν = 2990, 2918,

2851, 1469, 1311, 1159, 1081 cm⁻¹. ¹H NMR (400 MHz, CDCl₃) δ 8.49

(s, 1H_ar), 8.01−7.89 (m, 4H_ar), 7.67 (td, J = 7.4, 1.3 Hz, 1H_ar), 7.62 (td,

J = 7.4, 1.2 Hz, 1H_ar), 4.12−4.04 (m, 1H (CH−O)), 3.66 (dd, J = 7.4,

5.8 Hz, 1H (CH−O)), 3.00 (td, J = 7.2, 4.4 Hz, 1H (CH−N)), 2.72 (d,

A part of an AB system, J = 7.0 Hz, 1H (CH₂−N)), 2.25 (d, B part of an

AB system, J = 4.4 Hz, 1H (CH₂−N)), 1.58−1.46 (m, 1H), 1.44 (s, 3H

(CH₃)), 1.43−1.31 (m, 3H), 1.30 (s, 3H (CH₃)), 1.29−1.19 (m, 15H),

1.19−1.11 (m, 5H), 1.09−0,98 (m, 2H), 0.88 (t, J = 6.8 Hz, 3H (CH₃)).

¹³C NMR (101 MHz, CDCl₃) δ 135.6 (C_ar), 134.9 (C_ar), 132.2 (C_ar),

(Z)-(S)-2-((4S,5R)-2,2-Dimethyl-5-tetradecyl-1,3-dioxolan-4-

yl)-1-tetracos-15-enoylaziridine (14).

129.9 (CH_ar), 129.7 (2CH_ar), 129.6 (CH_ar), 128.2 (CH_ar), 127.9

(CH_ar), 123.3 (CH_ar), 108.6 (C), 78.5 (CH−O), 77.8 (CH−O), 38.4

(CH−N), 32.2 (CH₂), 31.5 (CH₂−N),30.0 (3CH₂), 29.8 (2CH₂), 29.6

(2CH₂), 29.5 (CH₂), 28.3 (CH₃), 27.0 (CH₂), 25.6 (CH₃), 23.0 (CH₂),

14.4 (CH₃). HRMS (ESI-TOF) m/z: [M + H]⁺calcd for C₃₁H₄₈NO₄S,

530.3304; found, 530.3329. Mp: 77−79 °C.

(4S,5R)-4-((S)-1-Azido-2-((tert-butyldiphenylsilyl)oxy)ethyl)-

5-tetradecyl-1,3,2-dioxathiolane 2,2-Dioxide (9). Synthesized

according to literature procedure.²⁴

A mixture of nervonic acid (800.0 mg, 2.18 mmol) and thionyl chloride

(3 mL, 40.7 mmol) was heated to reﬂux and stirred for 2 h. After that, the

remaining thionyl chloride was coevaporated with toluene (4 × 3 mL) to

aﬀord (Z)-tetracos-15-enoyl chloride as a brown oil (830.0 mg, 99%),

which was used in the next reaction step without further puriﬁcation. ¹H

NMR (400 MHz, CDCl₃) δ 5.40−5.30 (m, 2H), 2.88 (t, J = 7.3 Hz, 2H),

2.07−1.95 (m, 4H), 1.71 (quin, J = 7.4 Hz, 4H), 1.39−1.22 (m, 30H),

0.88 (t, J = 6.9 Hz, 3H). IR (ﬁlm): ν = 3007, 2925, 2854, 1801, 1465 cm⁻¹.

Then, to a solution of (S)-2-((4S,5R)-2,2-dimethyl-5-tetradecyl-1,3-

dioxolan-4-yl)aziridine (1)^20,21(276.0 mg, 0.81 mmol) in dry DCM (20

mL) was added triethylamine (218 μL, 1.76 mmol). The mixture was

cooled to −10 °C, and then a solution of (Z)-tetracos-15-enoyl chloride

(4.8 mL, 1.05 mmol) in DCM was added. The reaction mixture was

stirred and allowed to warm to room temperature overnight. Then, the

solvent was removed in vacuo to give a crude, which was puriﬁed by

ﬂash chromatography (silica gel, hexane/ethyl acetate 1:0 to 9.5:0.5,

gradient) to aﬀord the desired product 14 as a white solid (509 mg,

83%). [α]²⁰_D−24.1 (c 2.67, CHCl₃). IR (ﬁlm): ν = 2916, 2847, 1682,

1464, 1345, 1212, 1037 cm⁻¹. ¹H NMR (400 MHz, CDCl₃) δ 5.39−5.29

(m, 2H (2CH)), 4.20 (dt, J = 8.6, 5.5 Hz, 1H (CH−O)), 3.78 (dd, J =

6.8, 6.1 Hz, 1H (CH−O)), 2.67−2.60 (m, 1H (CH−N)), 2.43 (dt, A

part of an AB system, J_AB= 16.0 Hz, J = 7.6 Hz, 1H (CH₂−CO)), 2.35

(dt, B part of an AB system, J_AB= 16.0 Hz, J = 7.6 Hz, 1H (CH₂−CO)),

2.27 (dd, A part of an AB system, J = 5.9 Hz, J_AB= 0.9 Hz, 1H (CH₂−

N)), 2.22 (dd, B part of an AB system, J = 3.2 Hz, J_AB= 0.9 Hz, 1H

(CH₂−N)), 2.04−1.97 (m, 3H), 1.85−1.72 (m, 2H), 1.67−1.57 (m,

2H), 1.54−1.43 (m, 1H), 1.46 (s, 3H (CH₃)), 1.38−1.22 (m, 56H), 1.34

(s, 3H (CH₃)) 0.88 (t, J = 6.9 Hz, 6H (2CH₃)). ¹³C NMR (101 MHz,

CDCl₃) δ 185.8 (CO), 130.0 (2CH), 108.2 (C), 78.6 (CH−O),

78.0 (CH−O), 36.9 (CH₂−CO), 35.2 (CH−N), 32.1 (2CH₂), 29.9

(3CH₂), 29.8 (4CH₂), 29.7 (3CH₂), 29.5 (5CH₂), 28.5 (CH₂−N), 28.1

(CH₃), 27.4 (2CH₂−CC), 26.7 (CH₂), 25.5 (CH₃), 25.1 (CH₂), 22.9

(CH₂), 22.8 (CH₂), 14.3 (2CH₃). HRMS (ESI-TOF) m/z: [M + H]⁺

calcd for C₄₅H₈₅NO₃, 688.6608; found, 688.6629. Mp: 38−40 °C.

(2S,3R,E)-2-Azido-1-((tert-butyldiphenylsilyl)oxy)octadec-4-

en-3-ol (6).

To a solution of (4S,5R)-4-((S)-1-azido-2-((tert-butyldiphenylsilyl)-

oxy)ethyl)-5-tetradecyl-1,3,2-dioxathiolane 2,2-dioxide (9) (913 mg,

1.42 mmol) in dry toluene (13 mL) were added tetrabutylammonium

iodide (574.0 mg, 1.55 mmol) and DBU (319.4 mL, 2.14 mmol). The

resulting mixture was heated to reﬂux for 2 h, and then the solvent was

removed under reduced pressure to give a crude that was redissolved in

1,2-dioxane. To the previous solution was added p-toluenesulfonic

acid monohydrate until pH 2 (pH paper) was reached (420.0 mg,

2.20 mmol), and this mixture was stirred at room temperature overnight.

Then, the reaction mixture was diluted with 10% aq NaHCO₃(100 mL),

and extractions were done with AcOEt (3 × 100 mL). The collected

organic layers were dried over MgSO₄and ﬁltered, and the solvent was

removed under reduced pressure to give a crude that was puriﬁed by

ﬂash chromatography (silica gel, hexane/AcOEt 9.5:0.5) to aﬀord

alcohol 6 as a colorless oil (913 mg, 74%). Spectroscopic data accorded

with literature reference.²⁴¹H NMR (400 MHz, CDCl₃) δ 7.71−7.65

(m, 4H_ar), 7.48−7.37 (m, 6H_ar), 5.78−5.69 (dt, J = 15.4, 6.8 Hz, 1H),

5.43 (dd, J = 15.4, 7.2 Hz, 1H), 4.22 (t, J = 6.2 Hz, 1H), 3.85−3.75 (m,

2H), 3.51 (dd, J = 10.9, 5.2 Hz, 1H), 2.01 (dd, J = 13.9, 6.9 Hz, 2H),

1.37−1.21 (m, 23H), 1.07 (s, 9H), 0.88 (t, J = 6.7 Hz, 3H).

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(2S,3R,E)-2-Azido-1-((tert-butyldiphenylsilyl)oxy)-3-

resulting mixture was stirred and allowed to reach room temperature for

5 h. Then, the reaction mixture was diluted with DCM (20 mL), and the

organic layer was washed with satd aq NaHCO₃(3 × 20 mL). The

organic layer was dried with Na₂SO₄and ﬁltered, and the solvent was

removed under reduced pressure to give a crude that was puriﬁed by

ﬂash chromatography (silica gel, hexane/AcOEt 8:2) to aﬀord product

13 as a yellow oil (511.0 mg, 99%). [α]²⁰_D−93.0 (c 2.82, CHCl₃). IR

(ﬁlm): ν = 2925, 2854, 2141, 2102, 1466, 1362, 1179, 1157, 1031,

968 cm⁻¹. ¹H NMR (400 MHz, CDCl₃) δ 5.82 (dt, J = 15.4, 6.7 Hz, 1H

(CH (5))), 5.33 (dd, J = 15.4, 8.6 Hz, 1H (CH (4))), 4.71 (d, A

part of an AB system, J_AB= 6.7 Hz, 1H (CH₂(MOM))), 4.51 (d, B part

of an AB system, J_AB= 6.7 Hz, 1H (CH₂(MOM)), 4.38 (dd, A part of an

AB system, J_AB= 10.7 Hz, J = 3.5 Hz, 1H (CH₂−O (1))), 4.19 (dd, B

part of an AB system, J_AB= 10.7 Hz, J = 7.8 Hz, 1H (CH₂−O (1))), 4.13

(dd, J = 8.5, 5.6 Hz, 1H (CH−O)), 3.79−3.73 (m, 1H (CH−N₃)), 3.38

(s, 3H (CH₃(MOM))), 3.08 (s, 3H (CH₃(Ms))), 2.13−2.05 (m, 2H

(CH₂−CC)), 1.43−1.34 (m, 2H), 1.33−1.22 (m, 20H), 0.88 (t, J =

6.8 Hz, 3H (CH₃)). ¹³C NMR (101 MHz, CDCl₃) δ 139.9 (CH (5)),

124.4 (CH (4)), 93.3 (CH₂(MOM)), 75.9 (CH−O), 68.3 (CH₂−O

(1)), 63.6 (CH−N₃), 56.0 (CH₃(MOM)), 37.8 (CH₃(Ms)), 32.5

(CH₂−CC), 32.1 (CH₂), 29.8 (3CH₂), 29.7 (CH₂), 29.6 (CH₂), 29.5

(CH₂), 29.3 (CH₂), 29.0 (CH₂), 22.8 (CH₂), 14.3 (CH₃). HRMS (ESI-

TOF) m/z: [M + Na]⁺calcd for C₂₁H₄₁N₃O₅SNa, 470.2665; found,

470.2677.

(methoxymethoxy)octadec-4-en (11).

A solution of (2S,3R,E)-2-azido-1-((tert-butyldiphenylsilyl)oxy)-

octadec-4-en-3-ol (6) (1.14 g, 2.03 mmol) and DIPEA (3.5 mL,

20.3 mmol) in dry DCM (26 mL) was cooled to 0 °C. Then, technical

grade chloromethyl methylether (1.1 mL, 10.14 mmol) was added, and

the resulting mixture was allowed to reach room temperature overnight.

Then, the reaction mixture was diluted with DCM (100 mL) and

washed with satd aq NH₄Cl (3 × 100 mL). The organic layer was dried

over Na₂SO₄and ﬁltered, and the solvent was removed under reduced

pressure to aﬀord product 11 as a colorless oil (1.1 g, 89%). [α]²⁰_D−50.4

(c 1.61, CHCl₃). IR (ﬁlm): ν = 3069, 3050, 2926, 2855, 2099, 1660−

1420, 1113, 1028 cm⁻¹. ¹H NMR (400 MHz, CDCl₃) δ 7.80−7.74 (m,

4H_ar), 7.52−7.41 (m, 6H_ar), 5.77 (dt, J = 15.5, 6.7 Hz, 1H (CH (5))),

5.39 (dd, J = 15.5, 8.5 Hz, 1H (CH (4))), 4.74 (d, A part of an AB

sytem, J_AB= 6.7 Hz, 1H (CH₂(MOM))), 4.55 (d, B part of an AB

system, J_AB= 6.7 Hz, 1H (CH₂(MOM)), 4.22 (dd, J = 8.5, 4.9 Hz, 1H

(CH−O)), 3.88−3.78 (m, 2H (CH₂−OSi)), 3.73−3.67 (m, 1H (CH−

N₃)), 3.34 (s, 3H (CH₃(MOM))), 2.15−2.07 (m, 2H (CH₂−CC)),

1.46−1.31 (m, 22H), 1.17 (s, 9H (^tBu)), 0.96 (t, J = 6.8 Hz, 3H (CH₃)).

¹³C NMR (101 MHz, CDCl₃) δ 138.2 (CH (5)), 135.7 (CH_ar), 133.1

(C_ar), 133.1 (C_ar), 129.9 (CH_ar), 127.8 (CH_ar), 125.1 (CH (4)),

93.2 (CH₂(MOM)), 75.9 (CH−O), 66.7 (CH−N₃), 63.8 (CH₂−OSi),

55.5 (CH₃(MOM)), 32.4 (CH₂−CC), 32.0 (CH₂), 29.8 (2CH₂),

29.7 (CH₂), 29.6 (CH₂), 29.5 (CH₂), 29.2 (CH₂), 29.0 (CH₂), 26.8

(CH₃(^tBu)), 22.8 (CH₂), 19.2 (C (^tBu)), 14.2 (CH₃). HRMS (ESI-

TOF) m/z: [M + Na]⁺calcd for C₃₆H₅₇N₃O₃NaSi, 630.4067; found,

630.4047.

(S)-2-((R,E)-1-(Methoxymethoxy)hexadec-2-en-1-yl)aziridine (2).

To a solution of product 13 (136.0 mg, 0.30 mmol) and triphenyl-

phosphine (123.2 mg, 0.46 mmol) in a 9:1 mixture of THF (2 mL) and

water (220 μL) was added DIPEA (106 μL, 0.61 mmol). The mixture

was stirred at room temperature for 4 h. Then, brine (50 mL) was added,

and the aqueous phase was extracted with AcOEt (3 × 50 mL). The

combined organic extracts were dried over MgSO₄and ﬁltered, and the

solvent was removed under reduced pressure. The residue was puriﬁed

by ﬂash chromatography (silica gel, hexane/AcOEt 6:4) to give aziridine

2 as a colorless oil (55.3 mg, 56%). [α]²⁰_D−83.3 (c 2.85, CHCl₃). IR

(ﬁlm): ν = 3307, 3063, 2990, 2924, 2853, 1466, 1150, 1098, 1040,

971 cm⁻¹. ¹H NMR (400 MHz, CDCl₃) δ 5.74 (dt, J = 15.4, 6.8 Hz, 1H

(CH₂−CH)), 5.35 (dd, J = 15.4, 8.0 Hz, 1H (O−CH−CH)), 4.70

(d, A part of an AB system, J_AB= 6.6 Hz, 1H (CH₂(MOM))), 4.56 (d, B

part of an AB system, J_AB= 6.6 Hz, 1H (CH₂(MOM))), 3.87 (dd, J =

7.7, 5.2 Hz, 1H (CH−O)), 3.36 (s, 3H (CH₃(MOM))), 2.16−2.10 (m,

1H (CH−N)), 2.09−2.02 (m, 2H (CH₂−CC)), 1.75 (d, A part of an

AB system, J = 5.4 Hz, 1H (CH₂−N)), 1.62 (d, B part of an AB system,

J = 3.3 Hz, 1H (CH₂−N)), 1.43−1.20 (m, 22H), 0.88 (t, J = 6.8 Hz, 3H

(CH₃)). ¹³C NMR (101 MHz, CDCl₃) δ 136.7 (CH₂−CH), 126.8

(O−CH−CH), 93.5 (CH₂(MOM)), 76.9 (CH−O signal is hidden

under the solvent peak), 55.5 (CH₃(MOM)), 33.2 (CH−N), 32.5

(CH₂), 32.1 (CH₂), 29.9 (CH₂), 29.8 (3CH₂), 29.6 (CH₂), 29.5 (CH₂),

29.3 (CH₂), 29.2 (CH₂), 22.9 (CH₂), 22.7 (CH₂), 14.3 (CH₃). HRMS

(ESI-TOF) m/z: [M + H]⁺calcd for C₂₀H₄₀NO₂, 326.3059; found,

326.3061.

(2S,3R,E)-2-Azido-3-(methoxymethoxy)octadec-4-en-1-ol (12).

To a solution of azide 11 (296 mg, 0.49 mmol) in dry THF (9 mL)

was added a 1 M solution of tetrabutylammonium ﬂuoride (975 μL,

0.975 mmol) in THF. The resulting solution was stirred at room

temperature for 2 h. Then, the reaction mixture was diluted with brine

(25 mL), and the aqueous layer was extracted with AcOEt (3 × 25 mL).

The combined organic extracts were dried over MgSO₄and ﬁltered,

and the solvent was removed under reduced pressure to get a crude that

was puriﬁed by ﬂash chromatography (hexane/AcOEt 8:2) to isolate

alcohol 12 as a colorless oil (148 mg, 82%). [α]²⁰−116.3 (c 1.138,

D

CHCl₃). IR (ﬁlm): ν = 3421, 2925, 2854, 2099, 1467, 1277, 1153,

1025 cm⁻¹. ¹H NMR (400 MHz, CDCl₃) δ 5.79 (dt, J = 15.4, 6.7 Hz, 1H

(CH (5))), 5.36 (dd, J = 15.4, 8.5 Hz, 1H (CH (4))), 4.72 (d, A

part of an AB system, J_AB= 6.7 Hz, 1H (CH₂(MOM)), 4.53 (d, B part of

an AB sytem, J_AB= 6.7 Hz, 1H (CH₂(MOM)), 4.14 (dd, J = 8.4, 5.9 Hz,

1H (CH−O)), 3.80−3.68 (m, 2H (CH₂−O (1))), 3.57−3.51 (m, 1H

(CH−N₃)), 3.39 (s, CH₃(MOM)), 2.08 (dd, J = 14.1, 7.2 Hz, 2H

(CH₂−CC)), 1.63 (br s, OH), 1.43−1.34 (m, 2H), 1.34−1.21 (m,

20H), 0.87 (t, J = 6.8 Hz, 3H (CH₃)). ¹³C NMR (101 MHz, CDCl₃) δ

138.8 (CH (5)), 125.3 (CH (4)), 93.4 (CH₂(MOM)), 77.1

(CH−O), 66.4 (CH−N₃), 62.6 (CH₂−O (1)), 55.9 (CH₃(MOM)),

32.5 (CH₂), 32.1 (CH₂), 29.8 (3CH₂), 29.7 (CH₂), 29.6 (CH₂), 29.5

(CH₂), 29.3 (CH₂), 29.0 (CH₂), 22.9 (CH₂), 14.3 (CH₃). HRMS (ESI-

TOF) m/z: [M + Na]⁺calcd for C₂₀H₃₉N₃O₃Na, 392.2889; found,

392.2873.

(S)-2-((R,E)-1-(Methoxymethoxy)hexadec-2-en-1-yl)-1-octa-

noylaziridine (16).

To a solution of (S)-2-((R,E)-1-(methoxymethoxy)hexadec-2-en-1-

yl)aziridine (2) (96.6 mg, 0.30 mmol) in dry DCM (6 mL) was added

triethylamine (73 μL, 0.52 mmol). The resulting mixture was cooled to

−10 °C, and then octanoyl chloride (67 μL, 0.39 mmol) was added

dropwise. The reaction mixture was stirred and allowed to warm to room

temperature overnight. Then, the solvent was removed in vacuo to give a

crude, which was puriﬁed by ﬂash chromatography (silica gel, hexane/

AcOEt 9:1) to aﬀord the desired acylated product 16 as a colorless oil

(2S,3R,E)-2-Azido-3-(methoxymethoxy)octadec-4-en-1-yl

Methanesulfonate (13).

A solution of alcohol 12 (424 mg, 1.15 mmol) and triethylamine

(524 μL, 3.79 mmol) in dry DCM (10 mL) was cooled to 0 °C. Then,

methanesulfonyl chloride (227 μL, 2.87 mmol) was added, and the

(131.7 mg, 98%). [α]²⁰−96.7 (c 1.14, CHCl₃). IR (ﬁlm): ν = 2958,

D

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2925, 2854, 1705, 1466, 1152, 1034 cm⁻¹. ¹H NMR (400 MHz, CDCl₃)

was added (1S)-(+)-10-camphorsulfonic acid (CSA). The resulting

mixture was stirred at room temperature overnight. Then the solvent

was removed in vacuo to give a crude, which was washed with base and/

or puriﬁed by ﬂash chromatography on silica gel to aﬀord the desired

diols.

δ 5.76 (dt, J = 15.5, 6.8 Hz, 1H (CH₂−CH)), 5.37 (dd, J = 15.5,

8.2 Hz, 1H (O−CH−CH)), 4.69 (d, A part of an AB system, J_AB

=

6.7 Hz, 1H (CH₂(MOM))), 4.56 (d, B part of an AB system, J_AB

6.7 Hz, 1H (CH₂(MOM))), 3.95 (dd, J = 8.1, 5.0 Hz, 1H (CH−O)),

3.35 (s, 3H (CH₃(MOM))), 2.57−2.51 (m, 1H (CH−N)), 2.47−2.30

(m, 3H (CH₂−CO and CH_AH_B−N)), 2.11 (d, J = 3.2 Hz, 1H (CH_AH_B−

N)), 2.06 (dd, J = 14.1, 7.1 Hz, 2H (CH₂−CC)), 1.67−1.57 (m, 2H),

1.42−1.33 (m, 2H), 1.33−1.19 (m, 28H), 0.87 (t, J = 6.7 Hz, 6H

(2CH₃)). ¹³C NMR (101 MHz, CDCl₃) δ 186.2 (CO), 137.6 (CH₂−

CH), 125.9 (O−CH−CH), 93.6 (CH₂(MOM)), 76.4 (CH−O),

55.5 (CH₃(MOM)), 39.2 (CH−N), 36.7 (CH₂−CO), 32.5 (CH₂),

32.1 (CH₂), 31.8 (CH₂), 29.8 (4CH₂), 29.6 (CH₂), 29.5 (CH₂), 29.4

(CH₂), 29.3 (CH₂), 29.2 (2CH₂), 28.3 (CH₂), 25.3 (CH₂), 22.8

(2CH₂), 14.3 (CH₃), 14.2 (CH₃). HRMS (ESI-TOF) m/z: [M + Na]⁺

calcd for C₂₈H₅₃NO₃Na, 474.3923; found, 474.3926.

(Z)-N-((2R,3S,4R)-3,4-Isopropylidenedioxy-1-(phenylthio)-

octadecan-2-yl)tetracos-15-enamide (18a).

(Z)-(S)-2-((R,E)-1-(Methoxymethoxy)hexadec-2-en-1-yl)-1-

tetracos-15-enoylaziridine (17).

Amide 18a was synthesized from 14 (24.1 mg, 0.035 mmol), thiophenol

(5 μL, 0.047 mmol), and DBU (6 μL, 0.040 mmol) in MeCN (500 μL),

according to General Procedure 1 (150 W, 689.5 kPa, 100 °C) to give

complete conversion after 15 min. After ﬂash chromatographic puri-

ﬁcation (silica gel, hexane/ethyl acetate 9.5:0.5 to 7:3, gradient), pure

adduct 18a was isolated as a white waxy solid (27.0 mg, 96%). [α]²⁰

D

−9.0 (c 2.8, CHCl₃). IR (ﬁlm): ν = 3300, 2999, 2917, 2849, 1650, 1534,

1463, 1373, 1221, 1063 cm⁻¹. ¹H NMR (400 MHz, CDCl₃) δ 7.45−7.40

(m, 2H_ar), 7.31−7.24 (m, 2H_ar), 7.23−7.15 (m, 1H_ar), 5.50 (d, J =

9.1 Hz, 1H (NH)), 5.40−5.29 (m, 2H (2CH)), 4.32−4.24 (m, 1H

(CH−N)), 4.16 (t, J = 6.3 Hz, 1H (CH−O (3)), 4.12−4.03 (m, 1H

(CH−O (4)), 3.26 (dd, A part of an AB system, J_AB= 14.0 Hz, J = 3.3 Hz,

1H (CH₂−S)), 3.16 (dd, B part of an AB system, J_AB= 14.0 Hz, J = 6.6

Hz, 1H (CH₂−S)), 2.06−1.96 (m, 6H (CH₂−CO and 2CH₂−CC)),

1.56−1.48 (m, 2H), 1.47−1.41 (m, 2H), 1.43 (s, 3H (CH₃)) 1.40−1.18

(m, 59H), 0.88 (t, J = 6.8 Hz, 6H (2CH₃)). ¹³C NMR (101 MHz,

CDCl₃) δ 172.7 (CO), 136.2 (C_ar), 130.6 (CH_ar), 130.0 (2CH),

129.2 (CH_ar), 126.8 (CH_ar), 108.2 (C), 78.0 (CH−O), 77.8 (CH−O),

48.7 (CH−N), 36.9 (CH₂−CO), 36.9 (CH₂−S), 32.1 (2CH₂), 30.0

(CH₂), 29.9 (2CH₂), 29.8 (4CH₂), 29.7 (CH₂), 29.6 (CH₂), 29.5

(3CH₂), 29.4 (CH₂), 29.2 (CH₂), 27.7 (CH₃), 27.4 (CH₂), 26.7

(CH₂), 25.7 (CH₂), 25.5 (CH₃), 22.9 (2CH₂), 14.3 (2CH₃). HRMS

(ESI-TOF) m/z: [M + H]⁺calcd for C₅₁H₉₂NO₃S, 798.6798; found,

798.6796.

To a solution of (S)-2-((R,E)-1-(methoxymethoxy)hexadec-2-en-1-

yl)aziridine (2) (166.0 mg, 0.51 mmol) in dry DCM (10 mL) was added

triethylamine (125 μL, 0.90 mmol). The resulting mixture was cooled to

−10 °C and a then a 218 mM solution of (Z)-tetracos-15-enoyl chloride

(2.8 mL, 0.61 mmol; for its preparation see 14) in DCM was added

dropwise. The reaction mixture was stirred and allowed to warm to

room temperature overnight. Then, the solvent was removed in vacuo

to give a crude, which was puriﬁed by ﬂash chromatography (silica

gel, hexane/ethyl acetate 1:0 to 9.5:0.5, gradient) to aﬀord the desired

aziridine 17 as a white solid (314.8 mg, 92%). [α]²⁰−65.4 (c 1.11,

D

CHCl₃). IR (ﬁlm): ν = 3008, 2957, 2918, 2849, 1682, 1467, 1149, 1088,

1022 cm⁻¹. ¹H NMR (400 MHz, CDCl₃) δ 5.75 (dt, J = 15.2, 6.7 Hz, 1H

(CH)), 5.36 (dd, J = 14.7, 7.4 Hz, 1H (CH)), 5.34−5.27 (m, 2H

(2CH (acyl))), 4.67 (d, A part of an AB system, J_AB= 6.7 Hz,

1H (CH₂(MOM))), 4.55 (d, B part of an AB sytem, J_AB= 6.7 Hz, 1H

(CH₂(MOM))), 3.94 (dd, J = 8.1, 5.0 Hz, 1H (CH−O)), 3.34 (s,

3H (CH₃(MOM))), 2.55−2.50 (m, 1H (CH−N)), 2.46−2.29 (m, 2H

(CH₂−CO)), 2.35 (d, A part of an AB sytem, J = 5.9 Hz, 1H (CH₂−N)),

2.10 (d, B part of an AB system, J = 3.3 Hz, 1H (CH₂−N))), 2.08−2.02

(m, 2H (CH₂−CC)), 2.02−1.95 (m, 4H (2CH₂−CC (acyl))),

1.67−1.55 (m, 2H), 1.47− 1.06 (m, 54H), 0.86 (t, J = 6.8 Hz, 6H

(2CH₃)). ¹³C NMR (101 MHz, CDCl₃) δ 186.0 (CO), 137.4

(CH), 129.9 (2CH), 125.9 (CH), 93.6 (CH₂(MOM)), 76.4

(CH−O), 55.4 (CH₃(MOM)), 39.2 (CH−N), 36.7 (CH₂−CO), 32.5

(CH₂−CC), 32.0 (CH₂), 32.0 (CH₂), 29.9 (2CH₂), 29.8 (4CH₂),

29.7 (2CH₂), 29.6 (2CH₂), 29.5 (2CH₂), 29.4 (CH₂), 29.3 (CH₂), 29.2

(CH₂), 28.2 (CH₂−N), 27.3 (2CH₂−CC (acyl)), 25.2 (CH₂), 22.8

(2CH₂), 14.2 (2CH₃). HRMS (ESI-TOF) m/z: [M + Na]⁺calcd for

C₄₄H₈₃NO₃Na, 696.6271; found, 696.6285. Mp: 38−39 °C.

Synthesis of 1-Thio-(phyto)sphingolipid Analogues. General

Procedure 1: Microwave-Enhanced Nucleophilic Ring-Opening

Reaction of Acylated Aziridine Derivatives with Thiols. In a 10-mL

vessel, a solution of aziridine derivative and thiol in MeCN was prepared.

Then, DBU was added, and the mixture was stirred for 3 min under

nitrogen. The vessel was sealed with a septum and placed into the

microwave cavity. The microwave source was then turned on. Constant

microwave irradiation with simultaneous air-cooling was used during the

entire reaction. The evolution of the reaction was monitored by TLC.

When judged complete, the reaction mixture was cooled to room

temperature, and the solvent was removed under reduced pressure to

yield the crude product. Flash chromatography on silica gel using a

mixture of hexane and ethyl acetate aﬀorded the pure ring-opened

products.

(Z)-N-((2R,3S,4R)-3,4-Dihydroxy-1-(phenylthio)octadecan-2-

yl)tetracos-15-enamide (19a).

To a solution of adduct 18a (23.4 mg, 0.029 mmol) in a mixture (7.2 mL)

of MeOH/DCM (2.6:1) was added CSA (13.6 mg, 0.059 mmol). The

resulting suspension was heated to 30 °C and stirred overnight. Then,

the solvent was removed under reduced pressure to give a crude that was

puriﬁed by ﬂash chromatography (silica gel, hexane/ethyl acetate 9:1 to

8:2, gradient) to aﬀord pure adduct 19a as a white waxy solid (16.0 mg,

72%). [α]²⁰−17.6 (c 1.0, CHCl₃). IR (ﬁlm): ν = 3316, 2999, 2957,

D

2919, 2850, 1639, 1527, 1468, 1067 cm⁻¹. ¹H NMR (400 MHz, CDCl₃)

δ 7.42−7.37 (m, 2H_ar), 7.32−7.25 (m, 2H_ar), 7.24−7.16 (m, 1H_ar), 5.96

(d, J = 7.6 Hz, 1H (NH)), 5.39−5.29 (m, 2H (2CH)), 4.13−4.03 (m,

1H (CH−N)), 3.86 (br s, 2H (2OH)), 3.67−3.57 (m, 2H (2CH−O)),

3.36 (d, J = 6.2 Hz, 2H (CH₂−S)), 2.08 (t, J = 7.6 Hz, 2H (CH₂−CO)),

2.05−1.96 (m, 4H (2CH₂−CC)), 1.70−1.57 (m, 2H), 1.57−1.50 (m,

2H), 1.39−1.17 (m, 56H), 0.88 (t, J = 6.8 Hz, 6H (2CH₃)). ¹³C NMR

(101 MHz, CDCl₃) δ 174.6 (CO), 135.7 (C_ar), 130.1 (CH), 130.0

(CH), 129.9 (2CH_ar), 129.3 (2CH_ar), 126.7 (CH_ar), 76.2 (CH−O),

73.4 (CH−O), 52.7 (CH−N), 36.8 (CH₂−CO), 34.6 (CH₂−S), 33.4

(CH₂), 32.1 (2CH₂), 30.0 (CH₂), 29.9 (2CH₂), 29.8 (6CH₂), 29.7

(2CH₂), 29.5 (4CH₂), 29.4 (CH₂), 27.4 (2CH₂−CC), 25.9 (CH₂),

General Procedure 2: Diol Deprotection Reaction of 1-Thio-

adducts. To a solution of the aziridine ring-opened product in MeOH

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25.7 (CH₂), 22.9 (CH₂), 22.8 (CH₂), 14.3 (2CH₃). HRMS (ESI-TOF)

m/z: [M + H]⁺calcd for C₄₈H₈₈NO₃S, 758.6485; found, 758.6495.

(Z)-N-((2R,3S,4R)-1-((4-(4-Bromophenyl)thiazol-2-yl)thio)-

3,4-isopropylidenedioxyoctadec an-2-yl)tetracos-15-enamide

(18b).

(m, 1H (CH−O (4))), 4.14 (dd, B part of an AB system, J_AB= 13.1 Hz,

J = 10.0 Hz, 1H (CH₂−S)), 2.52−2.39 (m, 2H (CH₂−CO)), 2.33−2.23

(m, 1H), 2.20−2.08 (m, 4H (2CH₂−CC)), 2.04−1.90 (m, 2H),

1.88−1.78 (m, 2H), 1.78−1.69 (m, 1H), 1.48−1.22 (m, 54H), 0.89 (t,

J = 6.8 Hz, 3H (CH₃)), 0.88 (t, J = 6.9 Hz, 3H (CH₃)). ¹³C NMR (101

MHz, pyridine) δ 173.7 (CO), 167.1 (C_ar), 154.5 (C_ar), 134.2 (C_ar),

132.5 (2CH_ar(phenyl)), 130.6 (2CH), 129.0 (2CH_ar(phenyl)),

122.6 (C_ar), 114.4 (CH_ar(thiazol)), 77.6 (CH−O (3)), 73.2 (CH−O

(4)), 52.0 (CH−N), 37.3 (CH₂−CO), 36.2 (CH₂), 34.6 (CH₂), 32.5

(2CH₂), 30.7 (CH₂), 30.5 (3CH₂), 30.4 (2CH₂), 30.3 (2CH₂), 30.2

(2CH₂), 30.1 (CH₂), 30.0 (3CH₂), 28.0 (CH₂), 27.9 (2CH₂−CC),

27.0 (CH₂), 26.8 (CH₂), 23.3 (2CH₂), 14.7 (2CH₃). HRMS (ESI-

TOF) m/z: [M + Na]⁺calcd for C₅₁H₈₇BrN₂O₃S₂, 941.5239; found,

941.5231. Mp: 145−147 °C.

(Z)-N-((2R,3S,4R)-3,4-Isopropylidenedioxy-1-(pyridin-2-

ylthio)octadecan-2-yl)tetracos-15-enamide (18c).

Product 18b was synthesized from 14 (39.2 mg, 0.057 mmol), 4-(4-

bromophenyl)-2-thiazolethiol (19.2 mg, 0.068 mmol), and DBU (9 μL,

0.060 mmol) in MeCN (570 μL) according to General Procedure 1

(150 W, 689.5 kPa, 100 °C) to give complete conversion after 35 min.

After ﬂash chromatographic puriﬁcation (silica gel, hexane/ethyl acetate

9.5:0.5 to 9:1, gradient), pure adduct 18b was isolated as a white solid

(48.3 mg, 88%). [α]²⁰_D+9.6 (c 4.83, CHCl₃). IR (ﬁlm): ν = 3296, 3004,

2961, 2917, 2850, 1653, 1540, 1470, 1440−1360, 1280−1200, 1110−

1000 cm⁻¹. ¹H NMR (400 MHz, CDCl₃) δ 7.75−7.71 (m, 2H_ar), 7.56−

7.51 (m, 2H_ar), 7.34 (s, 1H_ar), 6.23 (d, J = 8.7 Hz, 1H (NH)), 5.39−5.30

(m, 2H (2CH)), 4.43−4.35 (m, 1H (CH−N)), 4.23 (t, J = 6.0 Hz, 1H

(CH−O (3))), 4.20−4.13 (m, 1H (CH−O (4))), 3.65−3.55 (m, 2H

(CH₂−S)), 2.05−1.97 (m, 4H (2CH₂−CC)), 1.93 (dd, J = 14.8,

7.1 Hz, 2H (CH₂−CO)), 1.61−1.51 (m, 3H), 1.49 (s, 3H (CH₃)),

1.45−1.36 (m, 3H), 1.36−1.05 (m, 54H), 1.34 (s, 3H (CH₃)) 0.88 (t,

J = 6.8 Hz, 6H (2CH₃)). ¹³C NMR (101 MHz, CDCl₃) δ 173.1 (CO),

165.9 (C_ar), 154.1 (C_ar), 132.9 (C_ar), 132.2 (2CH_ar), 130.1 (CH),

130.1 (CH), 128.0 (2CH_ar), 122.6 (C_ar), 113.6 (CH_ar), 108.4 (C),

78.8 (CH−O (3)), 77.9 (CH−O (4)), 49.6 (CH−N), 37.0 (CH₂−CO),

36.6 (CH₂−S), 32.2 (2CH₂), 30.0 (3CH₂), 29.9 (4CH₂), 29.8 (2CH₂),

29.6 (4CH₂), 29.5 (2CH₂), 27.6 (CH₃), 27.5 (2CH₂), 27.0 (CH₂), 25.7

(CH₂), 25.6 (CH₃), 22.9 (CH₂), 22.9 (CH₂), 14.4 (2CH₃). HRMS

was not provided due to low sensitivity in the MS spectrometer. Mp:

102−104 °C.

Product 18c was synthesized from 14 (37.2 mg, 0.054 mmol), 2-

pyridinethiol (7.2 mg, 0.065 mmol), and DBU (9 μL, 0.060 mmol) in

MeCN (540 μL), according to General Procedure 1 (150 W, 689.5 kPa,

100 °C) to give complete conversion after 60 min. After puriﬁcation by

ﬂash chromatography (silica gel, hexane/ethyl acetate 9.5:0.5 + 1% aq

NH₃), the pure pyridine 18c was isolated as a white solid (34.7 mg,

80%). [α]²⁰_D+22.6 (c 1.13, CHCl₃). IR (ﬁlm): ν = 3285, 2996, 2953,

2917, 2849, 1850−1700, 1649, 1540, 1470−1365, 1240−1050 cm⁻¹. ¹H

NMR (400 MHz, CDCl₃) δ 8.39 (ddd, J = 4.9, 1.8, 0.9 Hz, 1H_ar), 7.47

(ddd, J = 8.0, 7.4, 1.8 Hz, 1H_ar), 7.22 (dt, J = 8.1, 0.9 Hz, 1H_ar), 7.00

(ddd, J = 7.3, 5.0, 1.0 Hz, 1H_ar), 6.86 (d, J = 7.4 Hz, 1H (NH)), 5.40−

5.30 (m, 2H (2CH)), 4.31−4.13 (m, 3H (CH−N and 2CH−O)),

3.57 (dd, A part of an AB system, J_AB= 14.7 Hz, J = 9.3 Hz, 1H (CH₂−

S)), 3.34 (dd, B part of an AB system, J_AB= 14.7 Hz, J = 2.9 Hz, 1H

(CH₂−S)), 2.07−1.96 (m, 4H (2CH₂−CC)), 1.96−1.85 (m, 2H

(CH₂−CO)), 1.72−1.60 (m, 2H), 1.59−1.46 (m, 1H), 1.49 (s, 3H

(CH₃)), 1.45−1.01 (m, 57H), 1.35 (s, 3H (CH₃)), 0.88 (t, J = 6.8 Hz,

6H (2CH₃)). ¹³C NMR (101 MHz, CDCl₃) δ 173.3 (CO), 159.4

(C_ar), 149.1 (CH_ar), 136.3 (CH_ar), 130.1 (CH), 130.0 (CH), 122.9

(CH_ar), 119.9 (CH_ar), 108.0 (C), 79.2 (CH−O), 77.8 (CH−O),

51.1 (CH−N), 37.0 (CH₂), 32.1 (2CH₂), 31.5 (CH₂), 29.9 (3CH₂),

29.8 (3CH₂), 29.7 (4CH₂), 29.5 (3CH₂), 29.3 (CH₂), 27.4 (CH₂), 27.3

(CH₃), 27.0 (CH₂), 25.7 (CH₂), 25.4 (CH₃), 22.9 (CH₂), 22.8 (CH₂),

14.3 (2CH₃). HRMS (ESI-TOF) m/z: [M + H]⁺calcd for

C₅₀H₉₁N₂O₃S, 799.6750; found, 799.6765. Mp: 88−90 °C.

(Z)-N-((2R,3S,4R)-1-((4-(4-Bromophenyl)thiazol-2-yl)thio)-

3,4-dihydroxy-octadecan-2-yl)tetracos-15-enamide (19b).

(Z)-N-((2R,3S,4R)-3,4-Dihydroxy-1-(pyridin-2-ylthio)-

octadecan-2-yl)tetracos-15-enamide (19c).

To a solution of amide 18b (43.0 mg, 0.045 mmol) in a mixture (3 mL)

of MeOH/DCM (5:2) was added CSA (20.8 mg, 0.090 mmol). The

resulting suspension was heated to 30 °C and stirred overnight. Then,

the solvent was removed under reduced pressure to give a crude that was

redissolved in AcOEt (25 mL) and washed with 1 N aq NaOH (3 ×

25 mL). After that, the solvent of the organic layer was removed in vacuo

to aﬀord pure diol 19b as a white solid (40.8 mg, 99%). [α]³⁴_D+5.1 (c

0.20, 1:1 MeOH/CHCl₃). IR (ﬁlm): ν = 3303, 3077, 2917, 2850, 1850−

1650, 1645, 1575, 1543, 1469, 1416, 1110−1000 cm⁻¹. ¹H NMR

(400 MHz, pyridine) δ 8.85 (d, J = 8.7 Hz, 1H (NH)), 8.01 (d, J = 8.5

Hz, 2H (2CH_ar(phenyl))), 7.75 (s, 1H (thiazol)), 7.60 (d, J = 8.5 Hz,

2H (2CH_ar(phenyl))), 7.02 (d, J = 4.7 Hz, 1H (OH (3))), 6.33 (d, J =

5.5 Hz, 1H (OH (4))), 5.57−5.49 (m, 2H (2CH)), 5.49−5.41 (m,

1H (CH−N)), 4.45 (dd, A part of an AB system, J_AB= 13.1 Hz, J =

3.5 Hz, 1H (CH₂−S)), 4.42−4.39 (m, 1H (CH−O (3))), 4.32−4.24

To a solution of amide 18c (21.0 mg, 0.026 mmol) in a mixture (2 mL)

of MeOH/CHCl₃(5:2) was added CSA (12.2 mg, 0.053 mmol). The

resulting suspension was heated to 30 °C and stirred overnight. Then,

the solvent was removed under reduced pressure to give a reaction crude

that was redissolved in AcOEt (15 mL) and washed with 1 N aq NaOH

(3 × 15 mL). After that, the solvent of the organic layer was removed in

vacuo to aﬀord pure diol 19c as a waxy white solid (16.7 mg, 84%).

[α]²⁰+23.5 (c 1.52, CHCl₃). IR (ﬁlm): ν = 3300, 2917, 2850, 1809,

D

1739, 1645, 1548, 1467, 1411, 1071 cm⁻¹. ¹H NMR (400 MHz, CDCl₃)

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δ 8.36 (br d, J = 5.0 Hz, 1H_ar), 7.53 (td, J = 7.7, 1.7 Hz, 1H_ar), 7.26 (t, J =

4.0 Hz, 1H_ar), 7.06 (br dd, J = 6.8, 5.6 Hz, 1H_ar), 6.51 (d, J = 7.9 Hz, 1H

(NH)), 5.39−5.29 (m, 2H (2CH)), 4.32−4.24 (m, 1H (CH−N)),

3.70−3.56 (m, 3H (2CH−O and A part of a CH₂−S AB system), 3.43

(dd, B part of an AB system, J_AB= 15.1 Hz, J = 3.6 Hz, 1H (CH₂−S)),

2.96 (br s, 2H (2OH)) 2.15 (t, J = 7.4 Hz, 2H (CH₂−CO)), 2.05−1.97

(m, 4H (2CH₂−CC)), 1.72−1.61 (m, 2H), 1.61−1.52 (m, 3H),

1.51−1.40 (m, 2H), 1.38−1.20 (m, 53H), 0.88 (t, J = 6.8 Hz, 6H

(2CH₃)). ¹³C NMR (101 MHz, CDCl₃) δ 174.0 (CO), 159.3 (C_ar),

149.0 (CH_ar), 136.9 (CH_ar), 130.0 (2CH), 123.2 (CH_ar), 120.3

(CH_ar), 74.9 (CH−O), 72.9 (CH−O), 52.9 (CH−N), 37.1 (CH₂−

CO), 32.6 (CH₂), 32.1 (CH₂−S), 32.1 (CH₂), 30.0 (CH₂), 29.9

(3CH₂), 29.8 (3CH₂), 29.7 (CH₂), 29.5 (4CH₂), 29.4 (CH₂), 27.4

(2CH₂−CC), 26.2 (CH₂), 25.9 (CH₂), 22.9 (CH₂), 22.8 (CH₂), 14.3

(2CH₃). HRMS (ESI-TOF) m/z: [M + H]⁺calcd for C₄₇H₈₆N₂O₃S,

759.6437; found, 759.6434.

J = 4.2 Hz, 1H (CH₂−S)), 3.07 (dd, B part of an AB system, J_AB=

13.9 Hz, J = 8.4 Hz, 1H (CH₂−S)), 2.77 (br s, 1H (OH)), 2.11 (t, J = 7.6

Hz, 2H (CH₂−CO)), 2.03 (q, J = 6.8 Hz, 2H (CH₂−CC)), 1.60−

1.51 (m, 2H), 1.37−1.22 (m, 30H), 0.87 (t, J = 6.7 Hz, 6H (2CH₃)). ¹³

C

NMR (101 MHz, CDCl₃) δ 174.4 (CO), 135.5 (C_ar), 134.9 (CH

(5)), 130.0 (CH_ar), 129.3 (CH_ar), 128.2 (CH (4)), 126.8 (CH_ar),

74.6 (CH−O), 54.1 (CH−N), 36.8 (CH₂−CO), 34.4 (CH₂−S), 32.5

(CH₂), 32.1 (CH₂), 31.8 (CH₂), 29.9 (CH₂), 29.8 (2CH₂), 29.7 (CH₂),

29.5 (CH₂), 29.4 (CH₂), 29.3 (2CH₂), 29.2 (CH₂), 25.8 (CH₂), 22.9

(CH₂), 22.8 (CH₂), 14.3 (CH₃), 14.2 (CH₃). HRMS (ESI-TOF) m/z:

[M + H]⁺calcd for C₃₂H₅₆NO₂S, 518.4032; found, 518.4026. Mp: 75−

77 °C.

N-((2R,3R,E)-1-((2-(Hydroxymethyl)phenyl)thio)-3-

(methoxymethoxy)octadec-4-en-2-yl) octanamide (18e).

N-((2R,3R,E)-3-(Methoxymethoxy)-1-(phenylthio)octadec-4-

en-2-yl)octanamide (18d).

Ring-opened product 18e was synthesized from 16 (36.8 mg,

0.082 mmol), 2-mercaptobenzyl alcohol (14 mg, 0.098 mmol), and

DBU (13 μL, 0.087 mmol) in MeCN (800 μL) according to General

Procedure 1 (150 W, 689.5 kPa, 100 °C) to almost complete conversion

after 20 min. After ﬂash chromatographic puriﬁcation (silica gel, hexane/

AcOEt 8:2), pure product 18e was isolated as a white solid (29.0 mg,

60% yield, 71% conversion). [α]²⁰_D−51.7 (c 2.94, CHCl₃). IR (ﬁlm):

Octanamide 18d was synthesized from 16 (28.3 mg, 0.063 mmol),

thiophenol (8 μL, 0.078 mmol), and DBU (10 μL, 0.067 mmol) in

MeCN (600 μL) according to General Procedure 1 (150 W, 689.5 kPa,

100 °C) to give complete conversion after 5 min. After ﬂash chro-

matographic puriﬁcation (silica gel, hexane/AcOEt 8.5:1.5), pure

1

ν = 3291, 3063, 2955, 2924, 2853, 1647, 1545, 1466, 1024 cm⁻¹. H

NMR (400 MHz, CDCl₃) δ 7.43 (d, J = 7.4 Hz, 2H_ar), 7.25−7.18 (m,

2H_ar), 6.00 (d, J = 8.5 Hz, 1H (NH)), 5.76−5.65 (dt, J = 15.2, 6.6 Hz, 1H

(CH (5))), 5.25 (dd, J = 15.2, 6.6 Hz, 1H (CH (4))), 4.88 (d, A

part of an AB system, J_AB= 12.7 Hz, 1H (CH₂benz)), 4.66−4.60 (m, 2H

(B part of a CH₂benz AB system and A part of a CH₂(MOM) AB

system), 4.51 (d, B part of an AB system, J_AB= 6.6 Hz, 1H (CH₂

(MOM))), 4.21−4.09 (m, 2H (CH−N and CH−O))), 3.35 (s, 3H

(CH₃(MOM))), 3.25 (dd, A part of an AB system, J_AB= 13.8 Hz, J = 2.4

Hz, 1H (CH₂−S))), 3.07 (dd, B part of an AB system, J_AB= 13.8 Hz, J =

7.4 Hz, 1H (CH₂−S))), 2.95 (br s, 1H (OH)), 2.06−1.97 (m, 4H

(CH₂−CO and CH₂−CC)), 1.54−1.47 (m, 2H), 1.36−1.22 (m,

30H), 0.89−0.84 (m, 6H (2CH₃)). ¹³C NMR (101 MHz, CDCl₃) δ

173.4 (CO), 142.0 (C_ar), 137.3 (CH (5)), 134.4 (C_ar), 131.2

(CH_ar), 129.6 (CH_ar), 128.4 (CH_ar), 127.2 (CH_ar), 125.8 (CH (4)),

94.3 (CH₂(MOM)), 78.5 (CH−O), 63.2 (CH₂benz), 55.9 (CH₃

(MOM)), 52.3 (CH−N), 36.8 (CH₂−CO or CH₂−CC), 35.6

(CH₂−S), 32.5 (CH₂−CO or CH₂−CC), 32.1 (CH₂), 31.8 (CH₂),

29.8 (3CH₂), 29.6 (CH₂), 29.5 (CH₂), 29.4 (CH₂), 29.3 (CH₂), 29.2

(2CH₂), 25.6 (CH₂), 22.8 (CH₂), 22.8 (CH₂), 14.3 (CH₃), 14.2 (CH₃).

HRMS (ESI-TOF) m/z: [M + H]⁺calcd for C₃₅H₆₁NO₄S, 592.4400;

found, 592.4385. Mp: 62−64 °C.

product 18d was isolated as a colorless oil (31.8 mg, 90%). [α]²⁰

D

−68.5 (c 1.05, CHCl₃). IR (ﬁlm): ν = 3292, 3053, 2949, 2924, 2853,

1

1646, 1546, 1480−1430,1027 cm⁻¹. H NMR (500 MHz, CDCl₃) δ

7.38 (d, J = 7.3 Hz, 2H_ar), 7.30−7.25 (m, 2H_ar), 7.17 (t, J = 7.4 Hz, 1H_ar),

5.73 (dt, J = 15.4, 6.9 Hz, 1H (CH (5))), 5.68 (d, J = 8.9 Hz, 1H

(NH)), 5.29 (dd, J = 15.4, 7.7 Hz, 1H (CH (4))), 4.66 (d, A part of an

AB system, J_AB= 6.6 Hz, 1H (CH₂(MOM))), 4.52 (d, B part of an AB

system, J_AB= 6.6 Hz, 1H (CH₂(MOM))), 4.30−4.23 (m, 1H (CH−

N)), 4.21−4.17 (m, 1H (CH−O)), 3.36 (s, 3H (CH₃(MOM))), 3.21

(d, J = 5.7 Hz, 2H (CH₂−S)), 2.08−2.01 (m, 4H (CH₂−CO and CH₂−

CC)), 1.57−1.51 (m, 2H), 1.38−1.23 (m, 30H), 0.88 (t, J = 6.9 Hz,

3H (CH₃)), 0.87 (t, J = 6.9 Hz, 3H (CH₃)). ¹³C NMR (101 MHz,

CDCl₃) δ 172.8 (CO), 137.4 (CH (5)), 136.6 (C_ar), 129.5 (CH_ar),

129.1 (CH_ar), 126.3 (CH_aror CH (4)), 126.0 (CH_aror CH (4)),

94.2 (CH₂(MOM)), 78.0 (CH−O), 55.9 (CH₃(MOM)), 52.0 (CH−

N), 37.0 (CH₂−CO or CH₂−CC), 34.5 (CH₂−S), 32.5 (CH₂−CO

or CH₂−CC), 32.1 (CH₂), 31.8 (CH₂), 29.8 (3CH₂), 29.6 (CH₂),

29.5 (CH₂), 29.4 (2CH₂), 29.2 (2CH₂), 25.7 (CH₂), 22.8 (2CH₂), 14.3

(CH₃), 14.2 (CH₃). HRMS (ESI-TOF) m/z: [M + H]⁺calcd for

C₃₄H₆₀NO₃S, 562.4294; found, 562.4296.

N-((2R,3R,E)-3-Hydroxy-1-((2-(hydroxymethyl)phenyl)thio)-

octadec-4-en-2-yl)octanamide (19e).

N-((2R,3R,E)-3-Hydroxy-1-(phenylthio)octadec-4-en-2-yl)-

octanamide (19d).

To a solution of 18d (24.6 mg, 0.044 mmol) in MeOH (2 mL) was

added 37% aq hydrochloric acid (3 drops). The resulting solution was

heated to 64 °C and stirred at this temperature for 1 h. Then, the

reaction mixture was allowed to reach room temperature to remove the

volatiles under reduced pressure. The resulting residue was puriﬁed by

ﬂash chromatography (silica gel, hexane/AcOEt 8.5:1.5) to aﬀord

alcohol 19d as a pale yellow solid (17.0 mg, 75%). [α]²⁰_D−29.5 (c 1.57,

CHCl₃). IR (ﬁlm): ν = 3291, 3075, 2958, 2921, 2851, 1647, 1542,

1490−1365 cm⁻¹. ¹H NMR (400 MHz, CDCl₃) δ 7.36 (d, J = 7.8 Hz,

2H_ar), 7.29 (t, J = 7.6 Hz, 2H_ar), 7.20 (t, J = 7.3 Hz, 1H_ar), 5.80 (d, J =

7.0 Hz, 1H (NH)), 5.74 (dt, J = 15.4, 6.8 Hz, 1H (CH (5))), 5.43 (dd,

J = 15.4, 6.6 Hz, 1H (CH (4))), 4.27−4.23 (m, 1H (CH−O)), 4.12−

4.03 (m, 1H (CH−N)), 3.19 (dd, A part of an AB system, J_AB= 13.9 Hz,

To a solution of 18e (24.3 mg, 0.041 mmol) in MeOH (1.5 mL) was

added 37% aq hydrochloric acid (3 drops). The mixture was heated to

64 °C and stirred at this temperature for 1 h. Then, the reaction mixture

was allowed to reach room temperature to remove the volatiles under

reduced pressure. The resulting residue was puriﬁed by ﬂash

chromatography (silica gel, hexane/AcOEt 7:3) to aﬀord diol 19e as a

colorless oil (10.9 mg, 49%). IR (ﬁlm): ν = 3277, 3088, 2955, 2921,

2851, 1647, 1554, 1466, 1435, 1036 cm⁻¹. ¹H NMR (500 MHz, CDCl₃)

δ 7.46−7.41 (m, 2H_ar), 7.28−7.22 (m, 2H_ar), 6.08 (br d, J = 5.8 Hz, 1H

(NH)), 5.77−5.68 (m, 1H (CH (5))), 5.44−5.37 (m, 1H (CH

(4))), 4.86 (d, A part of an AB system, J_AB= 12.4 Hz, 1H (CH₂benz)),

4.69 (d, B part of an AB system, J_AB= 12.4 Hz, 1H (CH₂benz)),

4.26−4.20 (m, 1H (CH−O)), 4.05−3.97 (m, 1H (CH−N)), 3.25−3.15

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Article

(m, A part of an AB system, 1H (CH₂−S)), 3.08−3.00 (m, B part of an

AB system, 1H (CH₂−S)), 2.37 (br s, 2OH), 2.11−1.99 (m, 4H (CH₂−

CO and CH₂−CC)), 1.59−1.51 (m, 2H), 1.39−1.22 (m, 30H),

0.91−0.84 (m, 6H (2CH₃)). ¹³C NMR (75 MHz, CDCl₃) δ 173.6

(CO), 141.0 (C_ar), 133.7 (CH), 133.1 (C_ar), 130.8 (CH), 128.6

(CH), 127.7 (CH), 127.3 (CH), 126.6 (CH), 73.5 (CH−O), 62.5 (CH₂

benz), 53.2 (CH−N), 35.7 (CH₂), 34.3 (CH₂), 31.5 (CH₂), 31.1

(CH₂), 30.9 (CH₂), 28.9 (CH₂), 28.7 (CH₂), 28.5 (CH₂), 28.4 (CH₂),

28.3 (2CH₂), 28.2 (CH₂), 24.8 (CH₂), 21.8 (2CH₂), 13.3 (CH₃), 13.2

(CH₃). HRMS (ESI-TOF) m/z: [M + H]⁺calcd for C₃₃H₅₇NO₃S,

548.4137; found, 548.4133.

volatiles under reduced pressure. The resulting residue was redissolved

in MeOH (5.0 mL), and this solution was treated with a 25% methanolic

solution of sodium methoxide (23 μL, 0.10 mmol) for 10 min at room

temperature. After that, the solvent was removed in vacuo to give a

white solid. To this solid was added DCM (5 mL), and the resulting

suspension was ﬁltered. The solvent of the ﬁltrate was removed under

reduced pressure to give pure alcohol 19f as a pale yellow oil (13.6 mg,

76%). [α]²⁰_D+17.7 (c 1.25, 1:1 MeOH: CHCl₃). IR (ﬁlm): ν = 3296,

2961, 2919, 2850, 1900−1700, 1642, 1603, 1560−1400 cm⁻¹. ¹H NMR

(400 MHz, CD₃OD) δ 8.53−8.48 (m, 2H_ar), 7.98−7.93 (m, 2H_ar), 5.71

(dt, J = 15.2, 6.8 Hz, 1H (CH (5)), 5.47 (dd, J = 15.2, 7.3 Hz,

1H (CH (4))), 5.38−5.28 (m, 2H (2CH)), 4.17 (t, J = 7.5 Hz, 1H

(CH−O)), 4.09−4.03 (m, 1H (CH−N)), 3.45−3.33 (m, 2H (CH₂−

S)), 2.09 (t, J = 7.5 Hz, 2H (CH₂−CO)), 2.06−1.95 (m, 6H (3CH₂−

CC)), 1.56−1.42 (m, 3H), 1.42−1.17 (m, 53H), 0.90 (t, J = 6.8 Hz,

6H (2CH₃)). ¹³C NMR (101 MHz, CD₃OD) δ 176.0 (CO), 160.9

(C_ar), 159.9 (C_ar), 150.2 (2CH_ar), 142.3 (C_ar), 134.9 (CH (5)), 130.9

(CH (4)), 130.8 (2CH), 121.5 (2CH_ar), 74.0 (CH−O),

56.1 (CH−N), 37.3 (CH₂−CO), 35.4 (CH₂−S), 33.5 (CH₂−CC),

33.1 (2CH₂), 30.9 (2CH₂), 30.8 (2CH₂), 30.7 (CH₂), 30.6 (3CH₂),

30.5 (2CH₂), 30.4 (2CH₂), 30.3 (CH₂), 28.1 (2CH₂−CC), 27.1

(CH₂), 23.8 (CH₂), 14.5 (2CH₃). HRMS (ESI-TOF) m/z: [M + H]⁺

calcd for C₄₉H₈₆N₅O₂S, 808.6502; found, 808.6468.

(Z)-N-((2R,3R,E)-3-(Methoxymethoxy)-1-((5-(pyridin-4-yl)-1H-

1,2,4-triazol-3-yl)thio)octa dec-4-en-2-yl)tetracos-15-enamide

(18f).

(2R,3S,4R)-Tetra-O-acetyl-1-β-^D-glucopyranosylthio-3,4-iso-

propylidenedioxy-2-octanoylaminooctadecane (21) and

(2R,3S,4R)-Tetra-O-acetyl-1-α-^D-glucopyranosylthio-3,4-iso-

propylidenedioxy-2-octanoylaminooctadecane (22). Method A.

To a solution of aziridine 4 (20.9 mg, 0.045 mmol) and 1-thio-β-^D-

glucose tetraacetate (20) (19.5 mg, 0.054 mmol) in MeCN (380 μL)

was added DBU (7 μL, 0.049 mmol). The mixture was irradiated in a

microwave reactor (150 W, 689.5 kPa, 40 °C) for 35 min. Then the

solvent was removed under reduced pressure to give a crude, which was

puriﬁed by ﬂash chromatography (silica gel, hexane/ethyl acetate 8:2) to

get 21 as a yellow oil (9.5 mg, 26%) and 22 as a yellow oil (7.2 mg, 19%).

Method B. To a solution of aziridine 4 (25.1 mg, 0.054 mmol), 1-thio-

β-^D-glucose tetraacetate (20) (20.6 mg, 0.055 mmol), and tetra-n-

butylammonium hydrogensulfate (TBAHS) (73.6 mg, 0.22 mmol) in

AcOEt (210 μL) was added 1 M aq NaHCO₃(210 μL). The resulting

mixture was irradiated in a microwave reactor (150 W, 689.5 kPa,

40 °C), until total consumption of the starting thiol was observed by

TLC. Then, an additional 1 equiv of 1-thio-β-^D-glucose tetraacetate

(20.6 mg, 0.055 mmol) was added, and the mixture was irradiated under

the same conditions previously described, until the starting thiol was

consumed (15 min). Then, a third equivalent of 1-thio-β-^D-glucose

tetraacetate (20.6 mg, 0.055 mmol) was added, and another microwave

irradiation cycle was performed until total consumption of the starting

thiol (30 min). After that, the solvent was removed under reduced

pressure to give a crude, which was puriﬁed by ﬂash chromatography

(silica gel, hexane/ethyl acetate 7:3) to get 21 as a yellow oil (23.8 mg,

53%).

Product 18f was synthesized from 17 (33.0 mg, 0.049 mmol), 5-(4-

pyridinyl)-1H-1,2,4-triazole-3-thiol (10.5 mg, 0.059 mmol), and DBU

(8 μL, 0.054 mmol) in MeCN (500 μL) according to General Procedure

1 (150 W, 689.5 kPa, 100 °C) to give complete conversion after 30 min.

After ﬂash chromatographic puriﬁcation (silica gel, hexane/ethyl acetate

9.5:0.5 to 0:1 + 1% aq NH₃, gradient), pure pyridine 18f was isolated as a

pale yellow waxy solid (24.1 mg, 58%). ¹H NMR (400 MHz, CDCl₃) δ

8.68 (br d, J = 5.8 Hz, 2H (2CH_ar)), 7.99 (br d, J = 6.0 Hz, 2H (2CH_ar)),

6.60 (d, J = 7.5 Hz, 1H (NH−CO)), 5.82−5.72 (dt, A part of an AB

sytem, J_AB= 15.2 Hz, J = 7.0 Hz, 1H (CH (5))), 5.40−5.29 (m, 3H

(CH (4) and 2CH)), 4.66 (d, A part of an AB system, J_AB= 6.5 Hz,

1H (CH₂(MOM))), 4.61 (d, B part of an AB system, J_AB= 6.5 Hz, 1H

(CH₂(MOM))), 4.27−4.22 (m, 1H (CH−O)), 4.14−4.06 (m, 1H

(CH−N)), 3.40 (s, 3H (CH₃(MOM))), 3.22 (dd, A part of an AB

sytem, J_AB= 15.0 Hz, J = 7.4 Hz, 1H (CH₂−S)), 3.07 (dd, B part of an AB

sytem, J_AB= 15.0 Hz, J = 5.7 Hz, 1H ((CH₂−S))), 2.29 (t, J = 7.3 Hz, 2H

(CH₂−CO)), 2.10−1.96 (m, 6H (3CH₂−C)), 1.73−1.64 (m, 2H),

1.60 (br s, 1H (NH)), 1.39−1.18 (m, 54H), 0.88 (t, J = 6.9 Hz, 6H

(2CH₃)). ¹³C NMR (101 MHz, CDCl₃) δ 175.3 (CO), 161.3 (C_ar),

150.4 (2CH_ar), 138.5 (C_ar), 137.5 (CH (5)), 130.1 (CH (acyl)),

130.0 (CH (acyl)), 124.6 (CH (4)), 120.6 (C_ar), 95.1 (CH₂

(MOM)), 78.7 (CH−O), 56.1 (CH₃(MOM)), 54.0 (CH−N), 36.9

(CH₂−CO), 32.5 (CH₂−CC), 32.3 (CH₂−S), 32.1 (2CH₂),

29.9 (3CH₂), 29.8 (2CH₂), 29.7 (2CH₂), 29.6 (2CH₂), 29.5 (2CH₂),

29.4 (CH₂), 29.1 (CH₂), 27.4 (2CH₂−CC (acyl)), 25.7 (CH₂), 22.8

(CH₂), 14.3 (2CH₃). HRMS (ESI-TOF) m/z: [M + H]⁺calcd for

C₅₁H₉₀N₅O₃S, 852.6764; found, 852.6800.

(2R,3S,4R)-Tetra-O-acetyl-1-β-^D-glucopyranosylthio-3,4-iso-

propylidenedioxy-2-octanoylaminooctadecane (21).

(Z)-N-((2R,3R,E)-3-Hydroxy-1-((5-(pyridin-4-yl)-1H-1,2,4-tria-

zol-3-yl)thio)octadec-4-en-2-yl)tetracos-15-enamide (19f).

[α]²⁰_D−11.2 (c 0.94, CHCl₃). IR (ﬁlm): ν = 3322, 2958, 2923, 2853,

1745, 1648, 1376, 1233, 1043 cm⁻¹. ¹H NMR (500 MHz, CDCl₃) δ 5.77

(d, J = 8.9 Hz, 1H (NH)), 5.23 (t, J = 9.4 Hz, 1H (CH−O (3′))), 5.06 (t,

J = 9.8 Hz, 1H (CH−O (4′))), 4.99 (t, J = 9.7 Hz, 1H (CH−O (2′))),

4.52 (d, J = 10.1 Hz, 1H (O−CH-S)), 4.25 (dd, A part of an AB system,

J_AB= 12.4, 4.8 Hz, 1H (CH₂−O)), 4.22−4.16 (m, 1H (CH−N)), 4.16−

4.10 (m, 3H (CH−O (3), CH−O (4) and B part of a CH₂−O AB

system)), 3.69 (m, 1H (CH−O (5′))), 3.01 (dd, A part of an AB system,

J_AB= 13.9 Hz, J = 3.3 Hz, 1H (CH₂−S)), 2.86 (dd, B part of an

AB system, J_AB= 13.9 Hz, J = 7.2 Hz, 1H (CH₂−S)), 2.15 (td, J = 7.4,

3.2 Hz, 2H (CH₂−CO)), 2.09 (s, 3H (CH₃−COO)), 2.06 (s, 3H

To a solution of adduct 18f (19.0 mg, 0.022 mmol) in MeOH (5.0 mL)

was added 37% aq hydrochloric acid (6 drops). The mixture was heated

to 64 °C and stirred at this temperature for 1 h. Then, the reaction

mixture was allowed to warm to room temperature to remove the

3012

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Article

(CH₃−COO)), 2.03 (s, 3H (CH₃−COO)), 2.01 (s, 3H (CH₃−COO)),

1.62−1.58 (m, 4H), 1.55−1.49 (m, 3H), 1.45 (s, 3H (CH₃)), 1.36−1.16

(m, 29H), 1.33 (s, 3H (CH₃)) 0.88 (t, J = 6.8 Hz, 6H (2CH₃)). ¹³C

NMR (101 MHz, CDCl₃) δ 172.7 (NH-CO), 170.8 (OCO), 170.2

(OCO), 169.7 (OCO), 169.6 (OCO), 108.1 (C), 83.9 (O−

CH-S), 78.3 (CH−O), 77.8 (CH−O), 76.2 (CH−O (5′)), 73.8 (CH−

O (3′)), 70.0 (CH−O (2′)), 68.3 (CH−O (4′)), 62.0 (CH₂−O), 47.7

(CH−N), 36.9 (CH₂−CO), 32.8 (CH₂−S), 32.1 (CH₂), 31.8 (CH₂),

29.8 (2CH₂), 29.7 (CH₂), 29.5 (2CH₂), 29.2 (2CH₂), 27.7 (CH₃), 27.0

(CH₂), 25.8 (CH₂), 25.6 (CH₃), 22.8 (2CH₂), 20.9 (2CH₃(Ac)), 20.7

(2CH₃(Ac)), 14.3 (CH₃), 14.2 (CH₃). HRMS (ESI-TOF) m/z: [M +

H]⁺calcd for C₄₃H₇₆NO₁₂S, 830.5088; found, 830.5059.

1228, 1039 cm⁻¹. ¹H NMR (400 MHz, CDCl₃) δ 6.08 (d, J = 8.9 Hz,

1H), 5.22 (t, J = 9.5 Hz, 1H), 5.10−5.02 (m, 2H), 4.97 (t, J = 9.6 Hz,

2H), 4.43 (d, J = 10.1 Hz, 1H), 4.37 (m, 1H), 4.26−4.16 (m, 2H), 3.78−

3.72 (m, 1H), 3.01 (d, A part of an AB system, J_AB= 13.8 Hz, J = 3.7 Hz,

1H), 2.68 (dd, B part of an AB system, J_AB= 13.8 Hz, J = 7.0 Hz, 1H),

2.29 (t, J = 7.4 Hz, 2H), 2.09 (s, 6H), 2.06 (s, J = 5.7 Hz, 3H), 2.03 (s,

3H), 2.00 (s, 6H), 1.69−1.51 (m, 6H), 1.34−1.21 (m, 30H), 0.88 (t, J =

6.5 Hz, 6H). ¹³C NMR (101 MHz, CDCl₃) δ 173.8 (CO), 170.8

(CO), 170.4 (CO), 170.2 (CO), 170.0 (CO), 169.8 (CO),

169.6 (CO), 83.2 (CH), 76.2 (CH), 74.5 (CH), 73.7 (CH), 72.6

(CH), 69.7 (CH), 68.2 (CH), 62.0 (CH₂), 47.4 (CH), 34.5 (CH₂), 32.1

(CH₂), 31.8 (CH₂), 30.7 (CH₂), 29.9 (CH₂), 29.8 (CH₂), 29.7 (2CH₂),

29.5 (2CH₂), 29.2 (CH₂), 29.1 (CH₂), 28.9 (CH₂), 25.6 (CH₂), 25.0

(CH₂), 23.3 (CH₃), 22.8 (2CH₂), 21.1 (CH₃), 20.9 (2CH₃), 20.8

(CH₃), 20.7 (CH₃), 14.3 (CH₃), 14.2 (CH₃). HRMS (ESI-TOF) m/z:

[M + H]⁺calcd for C₄₄H₇₆NO₁₄S, 874.4987; found, 874.5027.

(2R,3S,4R)-1-β-^D-Glucopyranosylthio-3,4-dihydroxy-2-octa-

noylaminooctadecane (24).

(2R,3S,4R)-Tetra-O-acetyl-1-α-^D-glucopyranosylthio-3,4-iso-

propylidenedioxy-2-octanoylaminooctadecane (22).

[α]²⁰+64.9 (c 1.04, CHCl₃). IR (ﬁlm): ν = 3307, 2955, 2922, 2852,

D

1740, 1650, 1539, 1235, 1036 cm⁻¹. ¹H NMR (500 MHz, CDCl₃) δ 5.71

(d, J = 9.8 Hz, 1H (NH)), 5.62 (d, J = 5.7 Hz, 1H (O−CH-S)), 5.32 (t,

J = 9.8 Hz, 1H (CH−O (3′))), 5.03 (t, J = 10.0 Hz, 1H (CH−O (4′))),

5.01 (dd, J = 10.3, 5.8 Hz, 1H (CH−O (2′))), 4.44−4.39 (m, 1H (CH−

O (5′))), 4.30 (dd, A part of an AB system, J_AB= 12.6 Hz, J = 4.6 Hz, 1H

(CH₂−O)), 4.27 (m, 1H (CH−N)), 4.14 (dd, B part of an AB system,

J_AB= 12.6 Hz, J = 2.0 Hz, 1H (CH₂−O)), 4.12−4.08 (m, 1H (CH−O)),

4.07−4.03 (t, J = 6.5 Hz, 1H (CH−O)), 2.93 (dd, A part of an AB

system, J_AB= 14.5, J = 6.6 Hz, 1H (CH₂−S)), 2.84 (dd, B part of an AB

system, J_AB= 14.5 Hz, J = 2.6 Hz, 1H (CH₂−S)), 2.19−2.10 (m, 2H

(CH₂−CO)), 2.09 (s, 3H (CH₃−COO)), 2.06 (s, 3H (CH₃−COO)),

2.04 (s, 3H (CH₃−COO)), 2.01 (s, 3H (CH₃−COO)), 1.64−1.61 (br t,

J = 7.0 Hz, 2H), 1.56−1.44 (m, 4H), 1.42 (s, 3H (CH₃)), 1.34−1.22 (m,

30H), 1.32 (s, 3H (CH₃)), 0.90−0.85 (m, 6H (2CH₃)). ¹³C NMR (101

MHz, CDCl₃): δ 172.6 (NH-CO), 170.6 (OCO), 170.1 (OC

O), 169.9 (OCO), 169.8 (OCO), 108.4 (C), 84.4 (O−CH-S),

78.0 (CH−O), 77.7 (CH−O), 70.7 (CH−O (2′)), 70.4 (CH−O (3′)),

68.6 (CH−O (4′)), 68.2 (CH−O (5′)), 62.3 (CH₂−O), 48.6 (CH−N),

36.9 (CH₂−CO), 35.0 (CH₂−S), 32.1 (CH₂), 31.8 (CH₂), 29.9 (CH₂),

29.8 (2CH₂), 29.7 (2CH₂), 29.5 (2CH₂), 29.4 (CH₂), 29.2 (CH₂), 27.8

(CH₃), 26.8 (CH₂), 25.8 (CH₂), 25.7 (CH₃), 22.9 (CH₂), 22.8 (CH₂),

20.9 (2CH₃(Ac)), 20.8 (2CH₃(Ac)), 14.3 (CH₃), 14.2 (CH₃). HRMS

(ESI-TOF) m/z: [M + H]⁺calcd for C₄₃H₇₆NO₁₂S, 830.5088; found,

830.5084.

Method A. To a solution of 23 (8.0 mg, 9.2 μmols) in MeOH (1 mL)

was added a 220 mM methanolic solution of sodium methoxide

(550 μL, 121.0 μmol). The resulting mixture was stirred at room tem-

perature for 24 h. After this time the solvent was removed under reduced

pressure to give a crude, which was puriﬁed by reverse phase ﬂash

chromathography (C18 silica, 100% MeOH) to aﬀord product 24 as a

pale yellow solid (3.6 mg, 63%).

Method B. To a solution of 21 (46.0 mg, 0.055 mmol) in MeOH

(5 mL) was added CSA (27.4 mg, 0.12 mmol). The resulting mixture

was stirred at room temperature overnight. Then, the solvent was

removed under reduced pressure, and the crude was redissolved in

AcOEt (20 mL) and washed with 1 N aq NaOH (2 × 20 mL). The

organic layer was dried over MgSO₄and ﬁltered, and the solvent was

removed under reduced pressure to give a crude that was used without

further puriﬁcation. The previous crude was redissolved in MeOH

(4 mL), and a 220 mM methanolic solution of sodium methoxide (2 mL,

0.44 mmol) was added. The mixture was stirred at room temperature

overnight. After this period, the solvent was removed under reduced

pressure to give a crude, which was puriﬁed by reverse phase ﬂash

chromathography (C18 silica, 100% MeOH) to aﬀord product 24 as a

pale yellow solid (17.0 mg, 50%). [α]²⁰−37.6 (c 1.02, MeOH). IR

(2R,3S,4R)-Tetra-O-acetyl-1-β-^D-glucopyranosylthio-3,4-di-

acetoxy-2-octanoylaminooctadecane (23).

D

(ﬁlm): ν = 3440−3186, 2955, 2923, 2847, 1638, 1556, 1464, 1091−

1

1019 cm⁻¹. H NMR (400 MHz, Pyridine-d₅) δ 8.64 (d, J = 8.7 Hz,

1H (NH)), 5.33−5.25 (m, 1H (CH−N)), 5.18 (d, J = 9.0 Hz, 1H (O−

CH-S), 4.56 (dd, A part of an AB system, J_AB= 11.7 Hz, J = 2.0 Hz, 1H

(CH₂−O)), 4.38 (dd, J = 6.7, 4.6 Hz, 1H (CH−O (3))), 4.30 (dd, B part

of an AB system, J_AB= 11.7 Hz, J = 6.0 Hz, 1H (CH₂−O)), 4.22−4.12

(m, 4H (CH−O (4), CH−O (2′), CH−O (3′), CH−O (4′))), 4.01−

3.93 (m, 2H (CH−O (5′) and A part of a CH₂−S AB system))), 3.50

(dd, B part of an AB system, J_AB= 13.9 Hz, J = 9.4 Hz, 1H (CH₂−S)),

2.56−2.42 (m, 2H (CH₂−CO)), 2.31−2.22 (m, 1H), 1.97−1.88 (m,

2H), 1.88−1.79 (m, 2H), 1.74−1.64 (m, 1H), 1.49−1.11 (m, 28H), 0.99

(m, 2H), 0.88 (t, J = 6.8 Hz, 3H (CH₃)), 0.81 (t, J = 6.9 Hz, 3H (CH₃)).

¹³C NMR (101 MHz, Pyridine-d₅) δ 173.7 and 173.6 (CO, amide

rotamers), 87.0 (O−CH-S), 82.7 (CH−O (5′)), 80.1 (CH−O (2′)),

77.2 (CH−O (3)), 74.7 (CH−O), 72.7 (CH−O), 71.6 (CH−O), 63.0

(CH₂−O), 52.1 and 52.1 (CH−N, amide rotamers), 36.9 and 36.9

(CH₂−CO amide rotamers), 34.3 (CH₂), 32.1 (CH₂), 31.9 (CH₂), 31.1

(CH₂), 31.0 (CH₂), 30.3 (CH₂), 30.2 (CH₂), 30.0 (2CH₂), 29.9 (CH₂),

29.7 (CH₂), 29.6 (CH₂), 29.4 (CH₂), 26.6 (CH₂), 26.4 (CH₂), 22.9

(2CH₂), 14.3 (CH₃), 14.2 (CH₃). HRMS (ESI-TOF) m/z: [M + Na]⁺

calcd for C₃₂H₆₃NO₈SNa, 644.4172; found, 644.4171. Mp: 141−

143 °C.

To a solution of 21 (23.8 mg, 0.029 mmol) in dry MeOH (7 mL) was

added CSA (13.3 mg, 0.057 mmol). The mixture was stirred at room

temperature overnight. Then, the solvent was removed in vacuo to give a

crude that was used without further puriﬁcation. The previous crude

was redissolved in pyridine (10 mL), and acetic anhydride (97 μL,

1.02 mmol) was added. The mixture was stirred at room temperature

overnight. Then, the reaction mixture was cooled to 0 °C and MeOH

was added dropwise. The solvent was removed under reduced pressure

to give a crude that was redissolved in AcOEt and washed with water

(2 × 20 mL), satd aq NaHCO₃(2 × 20 mL), and 1 N aq HCl (2 ×

20 mL). The organic layer was dried over MgSO₄and ﬁltered, and the

solvent was removed under reduced pressure to give a crude, which was

puriﬁed by ﬂash chromatography (silica gel, hexane/ethyl acetate 7:3) to

get product 23 as a colorless oil (11.4 mg, 45%). [α]²⁰−4.4 (c 1.14,

D

CHCl₃). IR (ﬁlm): ν = 3304, 2949, 2924, 2854, 1747, 1653, 1545, 1378,

3013

dx.doi.org/10.1021/jo500061w | J. Org. Chem. 2014, 79, 2993−3029

The Journal of Organic Chemistry

Article

N-((2R,3S,4R)-3,4-Isopropylidenedioxy-1-(phenylthio)-

octadecan-2-yl)naphthalene-2-sulfonamide (25a).

(CH−N), 34.4 (CH₂−S), 33.5 (CH₂), 32.1 (CH₂), 29.9 (CH₂), 29.8

(3CH₂), 29.7 (CH₂), 29.5 (CH₂), 25.7 (CH₂), 22.9 (CH₂), 14.3 (CH₃).

HRMS (ESI-TOF) m/z: [M+K]⁺calcd for C₃₄H₄₉NO₄S₂K, 638.2740;

found, 638.2744 . Mp: 134−136 °C.

(2R,3S,4R)-Tetra-O-acetyl-1-β-^D-glucopyranosylthio-3,4-iso-

propylidenedioxy-2-(naphthalene-2-sulfonamido)octadecane

(25b).

To a solution of aziridine 15 (31.5 mg, 0.060 mmol) in a previously

degassed mixture of degassed AcOEt (1 mL) and 1 M aq NaHCO₃

(1 mL) were added TBAHS (81.6 mg, 0.24 mmol) and thiophenol

(11 μL, 0.11 mmol). The mixture was stirred vigorously at room tem-

perature overnight. Then, the reaction mixture was diluted with AcOEt

(10 mL) and satd aq NaHCO₃(10 mL). Next the organic layer was

washed with satd aq NaHCO₃(3 × 20 mL), dried over MgSO₄, and

ﬁltered, and the solvent was removed under reduced pressure to give a

residue that was puriﬁed by ﬂash chromatography (silica gel, hexane/

ethyl acetate 9:1) to aﬀord the desired product 25a as a white solid

Method A. To a solution of aziridine 15 (22.6 mg, 0.043 mmol) in a

mixture of AcOEt (850 μL) and 1 M aq NaHCO₃(850 μL) were added

TBAHS (58.5 mg, 0.17 mmol) and 1-thio-β-^D-glucose tetraacetate (20)

(20.4 mg, 0.054 mmol). The mixture was stirred vigorously at room

temperature for 3.5 h. Then, more 1-thio-β-^D-glucose tetraacetate (20)

(8.0 mg, 0.022 mmol) was added, and the reaction mixture was stirred at

room temperature overnight. The reaction mixture was diluted with

AcOEt (10 mL) and washed with aq satd NaHCO₃(3 × 10 mL). The

organic layer was dried over MgSO₄and ﬁltered, and the solvent was

removed under reduced pressure to give a residue that was puriﬁed by

ﬂash chromatography (silica gel, hexane/ethyl acetate 7:3) to aﬀord the

desired product 25b as a colorless oil (24.2 mg, 63%).

(37.0 mg, 96%). [α]²⁰−15.9 (c 1.02, CHCl₃). IR (ﬁlm): ν = 3268,

D

3053, 2986, 2923, 2852, 1587, 1502−1430, 1335, 1157 cm⁻¹. ¹H NMR

(400 MHz, CDCl₃) δ 8.40 (s, 1H_ar), 7.90 (dd, J = 17.2, 8.4 Hz, 3H_ar),

7.80 (dd, J = 8.7, 1.8 Hz, 1H_ar), 7.65 (td, J = 7.5, 1.4 Hz, 1H_ar), 7.63−7.58

(td, J = 7.5, 1.3 Hz, 1H_ar), 7.12−7.00 (m, 5H_ar), 5.16 (brd, J = 9.0 Hz, 1H

(NH)), 4.13 (t, J = 6.2 Hz, 1H (CH−O (3))), 4.05 (dd, J = 13.1, 6.2 Hz,

1H (CH−O (4))), 3.71−3.63 (m, 1H (CH−N)), 3.18 (dd, A part of an

AB system, J_AB= 14.0 Hz, J = 5.4 Hz, 1H (CH₂−S)), 2.82 (dd, B part of

an AB system, J_AB= 14.0 Hz, J = 3.5 Hz, 1H (CH₂−S)), 1.37 (s, 3H

(CH₃)), 1.36−1.30 (m, 3H), 1.30−1.21 (m, 17H), 1.21−1.16 (m, 4H),

1.15 (s, 3H (CH₃)), 1.10−1.01 (m, 2H), 0.88 (t, J = 6.8 Hz, 3H (CH₃)).

¹³C NMR (101 MHz, CDCl₃) δ 137.6 (C_ar), 135.2 (C_ar), 135.1 (C_ar),

Method B. To a solution of aziridine 15 (27.2 mg, 0.051 mmol), 1-

thio-β-^D-glucose tetraacetate (20) (19.1 mg, 0.052 mmol), and TBAHS

(71.5 mg, 0.21 mmol) in AcOEt (200 μL) was added 1 M aq NaHCO₃

(200 μL). The mixture was irradiated in a microwave reactor (150 W,

689.5 kPa, 40 °C), until total consumption of the starting thiol was

observed (15 min) by TLC. Then, an additional 1 equiv of 1-thio-β-^D-

glucose tetraacetate (20) (19.1 mg, 0.052 mmol) was added, and the

reaction mixture was irradiated under the same conditions previously

described, until total consumption of the starting aziridine was observed

(15 min). After that, the reaction mixture was diluted with AcOEt

(15 mL) and satd aq NaHCO₃(15 mL), and then extraction was done

with AcOEt (3 × 15 mL). The collected organic layers were dried over

MgSO₄and ﬁltered, and the solvent was removed in vacuo to give a

residue that was puriﬁed by ﬂash chromatography (silica gel, hexane/

ethyl acetate 7:3) to aﬀord the desired product 25b as a colorless oil

(31.0 mg, 69%). [α]²⁰_D+1.5 (c 1.14, CHCl₃). IR (ﬁlm): ν = 3284, 3056,

2986, 2926, 2853, 1751, 1223,1039 cm⁻¹. ¹H NMR (500 MHz, CDCl₃)

δ 8.46 (br s, 1H_ar), 8.00 (m, 2H_ar), 7.93 (d, J = 7.7 Hz, 1H_ar), 7.89 (dd, J =

8.7, 1.8 Hz, 1H_ar), 7.66 (td, J = 7.0, 1.3 Hz, 1H_ar), 7.62 (td, J = 6.7, 1.4 Hz,

1H_ar), 5.50 (d, J = 8.9 Hz, 1H (NH)), 5.17−5.08 (m, 2H (CH−O (3′)

and CH−O (4′))), 4.89 (t, J = 9.6 Hz, 1H (CH−O (2′))), 4.32 (dd, A

part of an AB system, J_AB= 12.5 Hz, J = 5.5 Hz, 1H (CH₂−O)), 4.24 (d,

J = 10.1 Hz, 1H (O−CH-S)), 4.12 (t, J = 6.4 Hz, 1H (CH−O)), 4.08

(dd, B part of an AB system, J_AB= 12.5 Hz, J = 2.1 Hz, 1H (CH₂−O)),

4.05−4.00 (m, 1H (CH−O)), 3.63−3.57 (m, 1H (CH−N)), 3.49−3.44

(m, 1H (CH−O (5′))), 2.91 (d, J = 4.2 Hz, 2H (CH₂−S)), 2.10 (s, 3H

(CH₃−COO)), 2.03 (s, 3H (CH₃−COO)), 2.02 (s, 3H (CH₃−COO)),

2.01 (s, 3H (CH₃−COO)), 1.36 (s, 3H (CH₃)), 1.34−1.18 (m, 20H),

1.27 (s, 3H (CH₃)), 1.16−1.03 (m, 4H), 0.99−0.92 (m, 2H), 0.88 (t, J =

6.9 Hz, 3H (CH₃)). ¹³C NMR (101 MHz, CDCl₃) δ 170.8 (CO),

170.2 (CO), 169.4 (CO), 169.3 (CO), 137.6 (C_ar), 134.9 (C_ar),

132.1 (C_ar), 129.7 (CH_ar), 129.4 (CH_ar), 129.0 (CH_ar), 128.4 (CH_ar),

128.0 (CH_ar), 127.8 (CH_ar), 122.7 (CH_ar), 108.0 (C), 83.8 (O−CH-S),

77.6 (CH−O (3 or 4)), 77.4 (CH−O (3 or 4)), 76.4 (CH−O (5′)), 73.7

(CH−O (3′ or 4′)), 69.6 (CH−O (2′)), 68.1 (CH−O (3′ or 4′)), 62.0

(CH₂−O), 52.2 (CH−N), 33.5 (CH₂−S), 32.0 (CH₂), 29.8 (2CH₂),

29.7 (2CH₂), 29.6 (CH₂), 29.4 (2CH₂), 27.7 (CH₃), 26.5 (CH₂), 25.6

(CH₃), 22.8 (CH₂), 20.9 (CH₃(Ac)), 20.8 (CH₃(Ac)), 20.7 (2CH₃

(2Ac)), 14.2 (CH₃). HRMS (ESI-TOF) m/z: [M + Na]⁺calcd for

C₄₅H₆₇NO₁₃NaS₂, 916.3952; found, 916.3977.

132.3 (C_ar), 130.8 (CH_ar), 129.8 (CH_ar), 129.5 (CH_ar), 129.1 (2CH_ar),

128.7 (CH_ar), 128.2 (CH_ar), 127.8 (CH_ar), 127.0 (CH_ar), 122.6 (CH_ar),

108.3 (C), 77.8 (CH−O (3)), 77.6 (CH−O (4)), 53.3 (CH−N), 37.4

(CH₂−S), 32.2 (CH₂), 30.0 (CH₂), 29.9 (CH₂), 29.8 (2CH₂),

29.6 (CH₂), 29.2 (CH₂), 27.7 (CH₃), 26.6 (CH₂), 25.5 (CH₃), 23.0

(CH₂), 14.4 (CH₃). HRMS (ESI-TOF) m/z: [M + Na]⁺calcd for

C₃₇H₅₃NO₄NaS₂, 662.3314; found, 662.3303. Mp: 88−90 °C.

N-((2R,3S,4R)-3,4-Dihydroxy-1-(phenylthio)octadecan-2-yl)-

naphthalene-2-sulfonamide (26).

To a solution of sulfonamide 25a (62.0 mg, 0.097 mmol) in MeOH

(8 mL) was added CSA (45.0 mg, 0.19 mmol). The mixture was stirred

at room temperature overnight. Then, the solvent was removed under

reduced pressure, and the crude was redissolved in AcOEt (20 mL) and

washed with 1 N aq NaOH (3 × 20 mL). The organic layer was dried

over MgSO₄and ﬁltered, and the solvent was removed in vacuo to give

product 26 as a yellow solid (56.0 mg, 96%). [α]²⁰−49.0 (c 1.11,

D

CHCl₃). IR (ﬁlm): ν = 3487, 3303, 3050, 2952, 2919, 2850, 1505−1376,

1328, 1162, 1076 cm⁻¹. ¹H NMR (400 MHz, CDCl₃) δ 8.32 (s, 1H_ar),

7.90−7.81 (m, 3H_ar), 7.76 (brd, J = 8.5 Hz, 1H_ar), 7.65 (t, J = 7.5 Hz,

1H_ar), 7.59 (t, J = 7.4 Hz, 1H_ar), 6.98−6.86 (m, 5H_ar), 5.40 (br d, J = 6.9

Hz, 1H (NH)), 3.85−3.79 (m, 1H (CH−O)), 3.74−3.60 (m, 2H (CH−

O, CH−N)), 3.20 (dd, A part of an AB system, J_AB= 14.1 Hz, J = 4.1 Hz,

1H (CH₂−S)), 3.06 (dd, B part of an AB system, J_AB= 14.1 Hz, J = 7.6

Hz, 1H (CH₂−S)), 1.69−1.55 (m, 2H), 1.46−1.36 (m, 2H), 1.33−1.21

(m, 22H), 0.88 (t, J = 6.1 Hz, 3H (CH₃)). ¹³C NMR (101 MHz, CDCl₃)

δ 136.3 (C_ar), 135.0 (C_ar), 134.5 (C_ar), 132.1 (C_ar), 129.6 (CH_ar), 129.5

(CH_ar), 129.0 (CH_ar), 128.9 (2CH_ar), 128.1 (CH_ar), 127.6 (CH_ar),

126.4 (CH_ar), 122.5 (CH_ar), 75.1 (CH−O), 72.8 (CH−O), 54.7

3014

dx.doi.org/10.1021/jo500061w | J. Org. Chem. 2014, 79, 2993−3029

The Journal of Organic Chemistry

Article

(2R,3S,4R)-Tetra-O-acetyl-1-β-D-glucopyranosylthio-3,4-

diacetoxy-2-(naphthalene-2-sulfonamido)octadecane (27).

added. The mixture was stirred at room temperature overnight. After

that, the solvent was removed in vacuo to give a crude, which was puriﬁed

by ﬂash chromathography (silica gel, dichloromethane/methanol 9:1)

to isolate product 28 as a white solid (23.0 mg, 56%). [α]²⁰−8.4 (c

D

2.05, MeOH). IR (ﬁlm): ν = 3534, 3499, 3420, 3161, 3053, 2923, 2852,

1466, 1442, 1317, 1148 cm⁻¹. ¹H NMR (500 MHz, Acetone-d₆) δ 8.51

(s, 1H_ar), 8.11 (t, J = 9.2 Hz, 2H_ar), 8.03 (d, J = 7.9 Hz, 1H_ar), 7.97 (dd,

J = 8.6, 1.1 Hz, 1H_ar), 7.72−7.64 (m, 2H_ar), 6.86 (d, J = 6.3 Hz, 1H

(NH)), 4.28 (d, J = 9.7 Hz, 1H (O−CH-S)), 3.92 (d, A part of an AB

system, J_AB= 11.1 Hz, 1H (CH₂−O)), 3.74−3.63 (m, 3H (CH−N,

CH−O (3), B part of a CH₂−O AB system)), 3.49−3.44 (m, 1H (CH−

O (4))), 3.42 (d, J = 9.2 Hz, 1H (CH−O (4′))), 3.34 (t, J = 8.6 Hz, 1H

(CH−O (3′))), 3.33−3.29 (m, 1H (CH−O (5′))), 3.18 (t, J = 9.1 Hz,

1H (CH−O (2′))), 3.11 (dd, A part of an AB system, J_AB= 14.5 Hz, J =

4.3 Hz, 1H (CH₂−S)), 2.89 (brs, 6OH), 2.78−2.71 (ddd, B part of an

AB system, J_AB= 14.5 Hz, J = 7.8, 1.3 Hz, 1H (CH₂−S)), 1.62−1.54 (m,

1H), 1.45−1.38 (m, 1H), 1.33−1.14 (m, 24H), 0.87 (t, J = 6.7 Hz, 3H

(CH₃)). ¹³C NMR (101 MHz, CD₃OD) δ 139.2 (C_ar), 136.3 (C_ar),

133.6 (C_ar), 130.4 (CH_ar), 130.4 (CH_ar), 129.8 (CH_ar), 129.4 (CH_ar),

129.0 (CH_ar), 128.6 (CH_ar), 124.1 (CH_ar), 87.4 (O−CH-S), 82.2 (CH−

O (5′)), 79.4 (CH−O (3′)), 76.6 (CH−O (3)), 74.3 (CH−O (2′)),

72.7 (CH−O (4)), 71.2 (CH−O (4′)), 62.7 (CH₂−O), 56.3 (CH−N),

33.8 (CH₂), 33.1 (CH₂), 31.7 (CH₂), 30.9 (CH₂), 30.8 (2CH₂), 30.5

(CH₂), 26.7 (CH₂), 23.8 (CH₂), 14.5 (CH₃). HRMS (ESI-TOF) m/z:

[M + H]⁺calcd for C₃₄H₅₆NO₉S₂, 686.3397; found, 686.3419. Mp:

162−164 °C.

To a solution of 25b (24.2 mg, 0.027 mmol) in dry MeOH (2 mL) was

added CSA (12.6 mg, 0.054 mmol). The mixture was stirred at room

temperature overnight. Then, the solvent was removed in vacuo to give a

crude that was used without further puriﬁcation. The previous crude was

redissolved in pyridine (1 mL), and acetic anhydride was added (68 μL,

0.72 mmol). The resulting mixture was stirred at room temperature for

24 h. Then, the reaction mixture was cooled to 0 °C, and MeOH was

added dropwise (5 mL). The solvent was removed under reduced

pressure and coevaporated with toluene (3 × 5 mL) to give a crude that

was puriﬁed by ﬂash chromatography (silica gel, hexane/ethyl acetate

7:3) to give product 27 as a colorless oil (22.9 mg, 90%). [α]²⁰_D−5.3 (c

2.41, CHCl₃₁). IR (ﬁlm): ν = 3265, 3059, 2925, 2854, 1752, 1371, 1224,

1039 cm⁻¹. H NMR (500 MHz, CDCl₃) δ 8.47 (s, 1H), 8.00 (t, J =

8.0 Hz, 2H), 7.94−7.88 (t, J = 9.2 Hz, 2H), 7.67−7.60 (m, 2H), 5.76 (d,

J = 8.8 Hz, 1H), 5.17 (t, J = 9.3 Hz, 1H), 5.10 (t, J = 9.7 Hz, 1H), 5.02

(dd, J = 6.6, 3.8 Hz, 1H), 4.90 (t, J = 9.5 Hz, 1H), 4.88−4.84 (m, 1H),

4.32 (d, J = 10.1 Hz, 1H), 4.29 (dd, J = 12.6, 5.4 Hz, 1H), 4.13 (dd, J =

12.5, 1.9 Hz, 1H), 3.77−3.71 (m, 1H), 3.61−3.56 (m, 1H), 3.04 (dd, J =

14.7, 3.9 Hz, 1H), 2.72 (dd, J = 14.7, 5.3 Hz, 1H), 2.11 (s, 3H), 2.04 (s,

3H), 2.03 (s, 3H), 2.02 (s, 3H), 2.00 (s, 3H), 1.97 (s, 3H), 1.32−1.17

(m, 18H), 1.14−1.07 (m, 3H), 1.05−0.91 (m, 5H), 0.87 (t, J = 6.9 Hz,

3H). ¹³C NMR (75 MHz, CDCl₃) δ 171.0 (CO), 170.7 (CO),

170.2 (CO), 169.9 (CO), 169.6 (CO), 169.5 (CO), 137.4

(C), 135.0 (C), 132.2 (C), 129.8 (CH), 129.4 (CH), 129.1 (CH), 128.6

(CH), 128.1 (CH), 127.9 (CH), 122.8 (CH), 83.4 (CH), 76.5 (CH),

73.9 (CH), 73.8 (CH), 72.7 (CH), 69.5 (CH), 68.2 (CH), 62.1 (CH₂),

52.2 (CH), 32.1 (CH₂), 31.9 (CH₂), 29.9 (CH₂), 29.8 (2CH₂), 29.7

(CH₂), 29.6 (CH₂), 29.5 (2CH₂), 28.9 (CH₂), 25.4 (CH₂), 22.8 (CH₂),

21.0 (2CH₃), 20.9 (CH₃), 20.8 (2CH₃), 20.7 (CH₃), 14.3 (CH₃).

HRMS (ESI-TOF) m/z: [M + H]⁺calcd for C₄₆H₆₈NO₁₅S₂, 938.4030;

found, 938.3999.

(2R,3S,4R)-1-β-^D-Glucopyranosylthio-2-acetamido-3,4-dihy-

droxyoctadecane (30).

To a solution of 27 (40.2 mg, 0.043 mmol) in dry MeOH (5 mL) were

added Mg (41.7 mg, 1.72 mmol) and ammonium chloride (9.2 mg,

0.17 mmol). The resulting mixture was sonicated for 1.5 h at room

temperature, at which time TLC on silica indicated that all starting

material had been consumed. The solvent was removed in vacuo to give a

crude that was used without further puriﬁcation. The previous crude was

redissolved in MeOH (5 mL), and 30% aq NH₃(420 μL) was added.

The mixture was stirred overnight at room temperature. Then, the

reaction mixture was cooled to 0 °C, and AcOEt (5 mL) was added

dropwise. Then, the solvent was removed under reduced pressure to

give a crude liquid, which was puriﬁed by reverse phase ﬂash chro-

mathography (on C18 silica, methanol/water 8:2 + 1% aq NH₃) to give

product 30 as a colorless oil (4.2 mg, 18%). [α]²⁰_Dwas not registered

because a low amount of product was obtained. IR (ﬁlm): ν = 3328,

2955, 2923, 2853, 1735, 1716, 1653, 1457, 1080, 1028 cm⁻¹. ¹H NMR

(500 MHz, CD₃OD) δ 4.39 (d, J = 9.6 Hz, 1H (O−CH-S)), 4.34 (dt, J =

(2R,3S,4R)-1-β-^D-Glucopyranosylthio-3,4-dihydroxy-2-(naph-

thalene-2-sulfonamido)octadecane (28).

8.1, 3.8 Hz, 1H (CH−N)), 3.88 (dd, A part of an AB system, J_AB

=

11.9 Hz, J = 1.5 Hz, 1H (CH₂−O)), 3.66−3.62 (m, B part of an AB

system, 1H (CH₂−O)), 3.53 (dd, J = 7.2, 4.6 Hz, 1H (CH−O (3))),

3.48−3.43 (m, 1H (CH−O (4))), 3.37−3.20 (m, some signals are

hidden under the solvent peak, 5H (CH−O (2′), CH−O (3′), CH−O

(4′), CH−O (5′) and A part of a CH₂−S AB system)), 2.68 (dd, B part

of an AB system, J_AB= 14.0 Hz, J = 10.1 Hz, 1H (CH₂−S)), 1.98 (s, 3H

(CH₃−CO)), 1.74−1.68 (m, 1H), 1.59−1.51 (m, 1H), 1.38−1.27 (m,

24H), 0.90 (t, J = 7.0 Hz, 3H (CH₃)). ¹³C NMR (101 MHz, CD₃OD) δ

173.2 (CO), 86.4 (O−CH-S), 82.1 (CH−O), 79.7 (CH−O), 77.1

(CH−O (3)), 74.3 (CH−O), 73.1 (CH−O (4)), 71.6 (CH−O), 63.0

(CH₂−O), 52.1 (CH−N), 34.3 (CH₂), 33.1 (CH₂), 30.8 (2CH₂), 30.7

(CH₂), 30.4 (2CH₂), 26.8 (CH₂), 23.7 (CH₃), 22.8 (CH₂), 14.4 (CH₃).

HRMS (ESI-TOF) m/z: [M + Na]⁺calcd for C₂₆H₅₁NO₈NaS,

560.3233; found, 560.3232.

Method A. To a solution of 27 (22.4 mg, 0.024 mmol) in MeOH

(100 μL) was added 30% aq NH₃(100 μL). The mixture was stirred at

room temperature for 3.5 h. Then, AcOEt (1 mL) was added dropwise,

and the solvent was removed under reduced pressure to give product 28

as a white solid (15.0 mg, 91%).

Method B. To a solution of 25b (158.0 mg, 0.18 mmol) in MeOH

(6 mL) was added CSA (82.0 mg, 0.35 mmol). The mixture was stirred

at room temperature overnight. Then, the solvent was removed under

reduced pressure, and the crude was redissolved in AcOEt (25 mL) and

washed with 1 N aq NaOH (2 × 25 mL). The organic layer was dried

over MgSO₄and ﬁltered, and the solvent was removed under reduced

pressure to give a crude that was used without further puriﬁcation. The

previous crude was redissolved in MeOH (7 mL) and a 220 mM

methanolic solution of sodium methoxide (3.6 mL, 0.79 mmol) was

3015

dx.doi.org/10.1021/jo500061w | J. Org. Chem. 2014, 79, 2993−3029

The Journal of Organic Chemistry

Article

(2R,3S,4R)-Tetra-O-acetyl-1-β-D-glucopyranosylthio-3,4-iso-

propylidenedioxy-2-((Z)-tetracos-15-enamido)octadecane

(31).

resulting suspension was heated to 30 °C and stirred overnight. Then,

the solvent was removed under reduced pressure to give a crude product

that was redissolved in MeOH (2 mL). To the previous solution

was added a 25% methanolic solution of sodium methoxide (74 μL,

0.32 mmol), and the resulting mixture was stirred at room temperature

overnight. Then, the solvent of the reaction mixture was removed in

vacuo to give a crude that was puriﬁed by ﬂash chromatography (C18

silica, water/MeOH 1:0 to 0:1, gradient) to aﬀord alcohol 32 as a white

solid (14.1 mg, 62%). [α]²⁶−20.6 (c 0.23, 1:1 MeOH/CHCl₃). IR

D

(ﬁlm): ν = 3319, 2917, 2849, 1635, 1521, 1462, 1276, 1073, 1037 cm⁻¹.

¹H NMR (400 MHz, 1:1 CD₃OD/CDCl₃, chemical shifts are referred to

the multiplet at δ = 3.31 ppm of CD₃OD) δ 5.36−5.26 (m, 2H

(2CH)), 4.36 (d, J = 9.6 Hz, 1H (CH−O)), 4.29−4.22 (m, 1H (CH−

N)), 3.86 (d, A part of an AB system, J_AB= 12.2 Hz, 1H (CH₂−O)),

3.67−3.60 (m, B part of an AB system, 1H (CH₂−O)), 3.56−3.50 (m,

1H (CH−O)), 3.49−3.42 (m, 1H (CH−O)), 3.39−3.33 (m, 1H (CH−

O)), 3.32−3.25 (2CH−O signal are hidden under the solvent peak),

3.28−3.24 (m, 1H (CH−O)) 3.19−3.12 (m, A part of an AB system, 1H

(CH₂−S)), 2.71 (dd, B part of an AB sytem, J_AB= 14.2 Hz, J = 9.2 Hz, 1H

(CH₂−S)), 2.23−2.14 (m, 2H (CH₂−CO)), 2.04−1.90 (m, 4H

(2CH₂−CC)), 1.70−1.45 (m, 5H), 1.42−0.96 (m, 56H), 0.89−

0.81 (m, 6H (2CH₃)). ¹³C NMR (101 MHz, 1:1 CD₃OD/CDCl₃,

chemical shifts are referred to the center line of the triplet at δ = 77.16

ppm of CDCl₃) δ 174.7 (CO), 129.5 (2CH), 85.2 (S−CH−O),

80.3 (CH−O) 78.0 (CH−O), 75.4 (CH−O), 72.3 (CH−O), 71.6

(CH−O), 69.8 (CH−O), 61.5 (CH₂−O), 50.6 (CH−N), 36.1 (CH₂),

31.5 (CH₂), 29.4 (CH₂), 29.3 (2CH₂), 29.2 (CH₂), 29.1 (2CH₂), 29.0

(CH₂), 28.9 (2CH₂), 26.8 (CH₂), 25.6 (CH₂), 22.3 (CH₂), 13.4

(2CH₃). HRMS (ESI-TOF) m/z: [M + Na]⁺calcd for C₄₈H₉₃NO₈SNa,

866.6520; found, 866.6483. Mp: 144−145 °C.

To a solution of aziridine 14 (50.0 mg, 0.073 mmol), 1-thio-β-D-glucose

tetraacetate (20) (26.5 mg, 0.073 mmol), and TBAHS (99.0 mg,

0.29 mmol) in AcOEt (280 μL) was added 1 M aq NaHCO₃(280 μL).

The mixture was irradiated in a microwave reactor (150 W, 689.5 kPa,

40 °C), until total consumption of the starting thiol was observed

(1.45 h) by TLC. Then, a second equivalent of 1-thio-β-^D-glucose

tetraacetate (26.5 mg, 0.073 mmol) was added, and the reaction mixture

was irradiated under the same conditions previously described, until

total consumption of the starting thiol was observed (1 h) by TLC.

Finally, a third equivalent of 1-thio-β-^D-glucose tetraacetate (26.5 mg,

0.073 mmol) was added, and another microwave irradiation cycle was

performed until total consumption of the thiol was observed (1 h). After

that, the reaction mixture was diluted with AcOEt (40 mL) and washed

with satd aq NaHCO₃(3 × 40 mL). The organic layer was dried over

MgSO₄and ﬁltered, and the solvent was removed under reduced

pressure to give a crude that was puriﬁed by ﬂash chromatography (silica

gel, hexane/ethyl acetate 9:1 to 7:3, gradient) to aﬀord pure adduct 31 as

a pale yellow waxy solid (19.7 mg, 26%). [α]²⁰_D−9.2 (c 1.78, CHCl₃). IR

(ﬁlm): ν = 3346, 3007, 2920, 2851, 1747, 1652, 1373, 1228, 1043 cm⁻¹.

¹H NMR (400 MHz, CDCl₃) δ 5.75 (d, J = 8.8 Hz, 1H (NH)), 5.39−

(2R,3R,E)-Tetra-O-acetyl-1-β-^D-glucopyranosylthio-3-(me-

thoxymethoxy)-2-((Z)-tetracos-15-enamido)octadec-4-ene

(35).

5.29 (m, 2H (2CH)), 5.22 (t, J = 9.4 Hz, 1H (CH−O (3′))), 5.05 (t,

J = 9.8 Hz, 1H (CH−O (4′))), 4.98 (t, J = 9.6 Hz, 1H (CH−O (2′))),

4.52 (d, J = 10.1 Hz, 1H (S−CH−O)), 4.24 (dd, A part of an AB system,

J_AB= 12.4 Hz, J = 4.9 Hz, 1H (CH₂−O)), 4.21−4.16 (m, 1H (CH−N)),

4.16−4.09 (m, 3H (CH−O (3), CH−O (4) and B part of a CH₂−O AB

system)), 3.69 (ddd, J = 10.1, 4.8, 2.2 Hz, 1H (CH−O (5′))), 3.01 (dd,

A part of an AB system, J_AB= 13.9 Hz, J = 3.4 Hz, 1H (CH₂−S)), 2.86

(dd, B part of an AB system, J_AB= 13.9 Hz, J = 7.1 Hz, 1H (CH₂−S)),

2.14 (td, J = 7.6, 3.2 Hz, 1H), 2.11−2.07 (m, 1H), 2.09 (s, 3H (CH₃−

COO)), 2.05 (s, 3H (CH₃−COO)), 2.04−1.97 (m, 4H), 2.02 (s, 3H

(CH₃−COO)), 2.00 (s, 3H (CH₃−COO)), 1.64−1.56 (m, 2H), 1.56−

1.48 (m, 3H), 1.45 (s, 3H (CH₃))), 1.39−1.19 (m, 55H), 1.32 (s, 3H

(CH₃)), 0.87 (t, J = 6.8 Hz, 6H (2CH₃)). ¹³C NMR (101 MHz, CDCl₃)

δ 172.7 (CO), 170.7 (CO), 170.2 (CO), 169.7 (CO), 169.5

(CO), 130.0 (2CH), 108.1 (C), 83.9 (S−CH−O), 78.3 (CH−O),

77.8 (CH−O), 76.3 (CH−O (5′)), 73.9 (CH−O (3′)), 70.0 (CH−O

(2′)), 68.4 (CH−O (4′)), 62.1 (CH₂−O), 47.8 (CH−N), 36.9 (CH₂−

CO), 32.8 (CH₂−S), 32.1 (2CH₂), 29.9 (3CH₂), 29.8 (4CH₂), 29.7

(2CH₂), 29.6 (2CH₂), 29.5 (3CH₂), 29.2 (CH₂), 27.7 (CH₃), 27.4

(2CH₂), 27.0 (CH₂), 25.8 (CH₂), 25.6 (CH₃), 22.8 (2CH₂), 20.9

(2CH₂), 20.7 (2CH₂), 14.3 (2CH₃). HRMS (ESI-TOF) m/z: [M + H]⁺

calcd for C₅₉H₁₀₆NO₁₂S, 1052.7436; found, 1052.7434.

To a solution of aziridine 17 (49.3 mg, 0.073 mmol) and 1-thio-β-D-

glucose tetraacetate (20) (80.0 mg, 0.22 mmol) in a previously degassed

mixture of AcOEt (560 μL) and 1 M aq NaHCO₃(560 μL) was added

TBAHS (99.0 mg, 0.29 mmol). The mixture was irradiated in a

microwave reactor (150 W, 689.5 kPa, 40 °C) for 2 h. After that, the

reaction mixture was diluted with AcOEt (20 mL) and washed with satd

aq NaHCO₃(3 × 20 mL). The organic layer was dried over MgSO₄and

ﬁltered, and the solvent was removed under reduced pressure to give a

crude that was puriﬁed by ﬂash chromatography (silica gel, hexane/ethyl

acetate 9.5:0.5 to 7:3, gradient) to aﬀord pure adduct 35 as a white waxy

solid (31.7 mg, 42%). [α]²⁷_D−34.9 (c 1.09, CHCl₃). IR (ﬁlm): ν = 3330,

2923, 2852, 1746, 1646, 1541, 1466, 1378, 1233, 1041 cm⁻¹. ¹H NMR

(400 MHz, CDCl₃) δ 5.83 (d, J = 8.5 Hz, 1H (NH)), 5.73 (dt, J = 15.5,

6.8 Hz, 1H (CH (5)), 5.38−5.26 (m, 3H (2CH (acyl) and

CH (4))), 5.23 (t, J = 9.4 Hz, 1H (CH−O), 5.07 (t, J = 9.9 Hz, 1H

(CH−O)), 5.01 (t, J = 9.5 Hz, 1H (CH−O)), 4.66 (d, A part of an AB

system, J_AB= 6.6 Hz, 1H (CH₂(MOM))), 4.53 (d, B part of an AB

system, J_AB= 9.8 Hz, 1H (S−CH−O)), 4.53 (d, J = 6.6 Hz, 1H (CH₂

(MOM)), 4.24 (dd, A part of an AB system, J_AB= 12.4 Hz, J = 4.8 Hz, 1H

(CH₂−O)), 4.21−4.17 (m, 1H (CH−N)), 4.14 (dd, B part of an AB

system, J_AB= 12.4 Hz, J = 2.3 Hz, 1H (CH₂−O)), 4.17−4.11 (m, 1H

(CH−O (3)), 3.77−3.72 (m, 1H (CH−O)), 3.36 (s, 3H (CH₃(MOM))),

2.98 (dd, A part of an AB system, J_AB= 13.4 Hz, J = 4.5 Hz, 1H (CH₂−S)),

2.85 (dd, B part of an AB system, J_AB= 13.4 Hz, J = 7.9 Hz, 1H (CH₂−S)),

2.16 (dd, J = 7.3, 2.3 Hz, 1H (CH₂−CO)), 2.14 (dd, J = 7.0, 1.9 Hz,

1H (CH₂−CO), 2.08 (s, 3H (CH₃−COO)), 2.05 (s, 3H (CH₃−COO)),

(2R,3S,4R)-1-β-^D-Glucopyranosylthio-3,4-dihydroxy-2-((Z)-

tetracos-15-enamido)octadecane (32).

To a solution of adduct 31 (28.3 mg, 0.027 mmol) in a mixture (500 μL)

of MeOH/CHCl₃(5:2) was added CSA (12.5 mg, 0.054 mmol). The

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2.02 (s, 3H (CH₃−COO)), 2.00 (s, 3H (CH₃−COO)), 2.10−1.97 (m,

6H (3CH₂−CC)), 1.66−1.55 (m, 2H), 1.39−1.18 (m, 54H), 0.88 (t,

J = 6.9 Hz, 6H (2CH₃)). ¹³C NMR (101 MHz, CDCl₃) δ 172.9 (CO),

170.7 (CO), 170.2 (CO), 169.8 (CO), 169.6 (CO), 137.4

(CH (5)), 130.0 (2CH (acyl)), 125.9 (CH (4)), 94.2 (CH₂

(MOM)), 83.6 (S−CH−O), 78.3 (CH−O), 76.2 (CH−O),

73.9 (CH−O), 70.0 (CH−O), 68.4 (CH−O), 62.2 (CH₂−O), 55.9

(CH₃(MOM)), 51.5 (CH−N), 37.0 (CH₂−CO), 32.5 (CH₂−CC),

32.1 (CH₂), 30.4 (CH₂), 29.9 (2CH₂), 29.8 (4CH₂), 29.7 (2CH₂), 29.6

(3CH₂), 29.5 (3CH₂), 29.4 (CH₂), 29.3 (CH₂), 27.4 (2CH₂−CC),

25.9 (CH₂), 22.8 (CH₂), 20.9 (CH₃−COO), 20.9 (CH₃−COO), 20.8

(CH₃−COO), 20.7 (CH₃−COO), 14.3 (2CH₃). HRMS (ESI-TOF)

m/z: [M + Na]⁺calcd for C₅₈H₁₀₃NO₁₂SNa, 1060.7099; found,

1060.7172.

To a solution of compound 36 (1.3 mg, 1.25 μmol) in MeOH (300 μL)

was added a 25% methanolic solution of sodium methoxide (4 μL,

0.017 mmol), and the resulting mixture was stirred at room temperature

overnight. Then, the solvent of the reaction mixture was removed in

vacuo to give a crude compound that was used without further puri-

ﬁcation in biological studies. ¹H NMR (400 MHz, 1:1 CDCl₃/CD₃OD,

chemical shifts are referred to the multiplet at δ = 3.31 ppm of CD₃OD)

δ 5.74−5.64 (m, 2H), 5.43 (d, J = 6.9 Hz, 1H), 5.39−5.30 (m, 2H), 4.36

(d, J = 9.7 Hz, 1H), 4.06−4.00 (m, 2H), 3.91−3.81 (m, 2H), 3.68−3.62

(m, 1H), 3.25−3.12 (m, 3H), 2.73 (dd, J = 13.7, 7.9 Hz, 2H), 2.19 (t, J =

7.4 Hz, 2H), 2.11−1.95 (m, 6H), 1.65−1.55 (m, 3H), 1.44−1.24 (m,

58H), 0.90 (t, J = 6.7 Hz, 6H). HRMS (ESI-TOF) m/z: [M + Na]⁺calcd

for C₄₈H₉₁NO₇SNa, 848.6414; found, 848.6436. This product was not

further characterized because of the low amount of crude obtained and

the insolubility of the ﬁnal product.

(2R,3R,E)-Tetra-O-acetyl-1-β-^D-glucopyranosylthio-3-ace-

toxy-2-((Z)-tetracos-15-enamido)octadec-4-ene (36).

Synthesis of Phosphorylated Analogues. S-((2R,3S,4R)-3,4-

Isopropylidenedioxy-2-octanamidooctadecyl) O,O-dibenzyl

Phosphorothioate (40).

To a solution of sulfur (43.5 mg, 1.36 mmol) in a mixture of dry AcOEt/

diethyl ether (1:1, 4 mL) was added dibenzyl phosphite (300 μL,

1.36 mmol). The resulting mixture was cooled to 0 °C, and

triethylamine (189 mL, 1.36 mmol) was added dropwise. The mixture

was stirred and allowed to reach room temperature overnight. Then, the

reaction mixture was ﬁltered, and the solid was washed with AcOEt/

diethyl ether (1:1, 15 mL). After that, the solvent of the resulting ﬁltrate

was removed under reduced pressure to give triethylammonium O,O-

dibenzyl phosphorothioate (38) as a yellow oil (530 mg, 99%). ¹H NMR

(500 MHz, CDCl₃) δ 12.14 (br s, 1H), 7.43−7.20 (m, 10H), 5.11−5.01

(m, 2H), 5.01−4.93 (m, 2H), 3.06−2.95 (m, 6H), 1.26 (t, J = 7.3 Hz,

9H). HRMS (ESI-TOF) m/z: [(BnO)₂POS]⁻calcd for C₁₄H₁₄O₃PS,

293.0401; found, 293.0378. Then, to a solution of triethylammonium

O,O-dibenzyl phosphorothioate (102 mg, 0.26 mmol) in dry diethyl

ether (25 mL) was added 1 M aq HCl (25 mL) dropwise over 5 min.

The organic layer was washed with 1 M aq HCl (3 × 25 mL), and the

solvent of the organic phase was dried over MgSO₄and ﬁltered, and the

solvent was removed under reduced pressure to give O,O-dibenzyl

S-hydrogen phosphorothioate (43) as a pale brown oil (65 mg, 85%).

¹H NMR (300 MHz, CDCl₃) δ 7.41−7.28 (m, 10H), 5.17−4.94 (m,

4H), 4.03 (d, J = 13.1 Hz) and 3.96 (d, J = 14.2 Hz) (1H).

Method A. To a solution of aziridine derivative 4 (25.9 mg,

0.05 mmol) in dry 1,2-dichloroethane (4 mL) was added a solution of

triethylammonium O,O-dibenzyl phosphorothioate (38) (28.6 mg,

0.07 mmol) in dry 1,2-dichloroethane (4 mL). The resulting solution

was heated to 75 °C and stirred at this temperature for 3 days. After that,

the reaction mixture was diluted with DCM (25 mL), and the organic

layer was washed with aq satd NaHCO₃(3 × 25 mL). Then, the organic

layer was dried over MgSO₄and ﬁltered, and the solvent was removed

in vacuo to give a crude that was puriﬁed by ﬂash chromatography (silica

gel, hexane/AcOEt 1:0 to 1:1, gradient) to aﬀord ring-opened product

40 as a colorless oil (11.0 mg, 26%). Compounds 41⁷¹and 42 were

isolated as reaction byproducts in the same reaction.

To a solution of adduct 35 (21.3 mg, 0.021 mmol) in MeOH (1.0 mL)

was added 37% aq hydrochloric acid (6 drops). The resulting mixture

was heated to 64 °C and stirred at this temperature for 1 h. Then, the

reaction mixture was allowed to warm to room temperature to remove

the volatiles under reduced pressure. The resulting residue was re-

dissolved in pyridine (780 μL), and acetic anhydride (30 μL, 0.31 mmol)

was added. This mixture was stirred at room temperature for 17 h, then

the reaction mixture was cooled to 0 °C, and MeOH was added

dropwise. The solvent was removed under reduced pressure to give a

crude that was redissolved in AcOEt (15 mL) and washed with 1 N aq

HCl (2 × 15 mL), satd aq NaHCO₃(2 × 15 mL), and brine (2 ×

15 mL). After that, the organic layer was dried over MgSO₄and ﬁltered,

and the solvent was removed under reduced pressure to give a colorless

oil that showed a mixture of products by ¹H NMR. The previous crude

was redissolved again in pyridine (780 μL), and acetic anhydride (30 μL,

0.31 mmol) was added. The resulting solution was stirred at room

temperature for 36 h, and then the solvent of the reaction mixture was

removed in vacuo. This crude was redissolved in AcOEt (15 mL), and

the same treatment with 1 N aq HCl, satd aq NaHCO₃and brine

previously described was done. The resulting crude was puriﬁed by ﬂash

chromatography (silica gel, hexane/ethyl acetate 9.5:0.5 to 7:3,

1

gradient) to aﬀord product 36 (1.3 mg, 6%). H NMR (400 MHz,

CDCl₃) δ 5.84−5.66 (m, 2H), 5.43−5.26 (m, 3H), 5.26−5.18 (t, J =

9.4 Hz, 1H), 5.12−5.04 (m, 1H), 5.01 (t, J = 9.6 Hz, 1H), 4.47 (d, J =

10.0 Hz, 1H), 4.38−4.28 (m, 1H), 4.28−4.03 (m, 3H), 3.78−3.71 (m,

1H), 2.94 (dd, J = 13.4, 4.5 Hz, 1H), 2.73 (dd, J = 13.4, 8.1 Hz, 1H),

2.22−2.11 (m, 2H), 2.11−1.96 (m, 15H), 1.66−1.48 (m, 12H), 1.45−

1.15 (m, 50H), 0.88 (t, J = 6.6 Hz, 6H). This product was not further

characterized because of the low amount of crude obtained and the

insolubility of the ﬁnal product.

(2R,3R,E)-1-β-^D-Glucopyranosylthio-3-hydroxy-2-((Z)-tetra-

cos-15-enamido)octadec-4-ene (37).

Method B. To a solution of O,O-dibenzyl S-hydrogen phosphor-

othioate (43) (65.0 mg, 0.22 mmol) in dry THF (5 mL) was added a

solution of 4 (79.2 mg, 0.17 mmol) in dry THF (5 mL). The resulting

mixture was heated to 75 °C and stirred for 24 h. Then, the reaction

mixture was diluted with AcOEt (25 mL), and the organic layer was

washed with satd aq NaHCO₃(3 × 25 mL). Then, the organic layer was

dried over MgSO₄and ﬁltered, and the solvent was removed in vacuo to

give a crude that was puriﬁed by ﬂash chromatography (silica gel,

hexane/AcOEt 9:1 to 0:1, gradient) to aﬀord ring-opened product 40 as

a colorless oil (35.0 mg, 27%). Compound 41⁷¹was isolated as reaction

byproduct in the same reaction.

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Data for Compund 40. ¹H NMR (300 MHz, CDCl₃) δ 7.40−7.29

(m, 10H), 6.31 (d, J = 8.9 Hz, 1H), 5.09 (t, J = 7.7 Hz, 4H), 4.34−4.19

(m, 1H), 4.17−4.07 (m, 2H), 3.16−2.95 (m, 2H), 2.21−2.07 (m, 2H),

1.65−1.52 (m, 2H), 1.39 (s, 3H), 1.31 (s, 3H), 1.34−1.19 (m, 34H),

0.95−0.81 (m, 6H). HRMS (ESI-TOF) m/z: [M + H]⁺calcd for

C₄₃H₇₁NO₆PS, 760.4740; found, 760.4791.

NMR (121 MHz, CDCl₃) δ 32.63. HRMS (ESI-TOF) m/z: [M + H]⁺

calcd for C₃₁H₆₃NO₆PS, 608.4114; found, 608.4142.

S-((2R,3S,4R)-3,4-Dihydroxy-2-octanamidooctadecyl) O,O-

Dimethyl Phosphorothioate (48).

S-((2R,3S,4R)-3,4-Isopropylidenedioxy-2-octanamidoocta-

decyl) O,O-dimethyl Phosphorothioate (46a).

To a solution of phosphorotioate 46a (41.4 mg, 0.068 mmol) in dry

MeOH (5 mL) was added CSA until pH 2 was reached. The resulting

mixture was stirred at room temperature overnight. Then, the solvent

of the reaction mixture was removed under reduced pressure to give a

crude that was puriﬁed by ﬂash chromatography (silica gel, hexane/

AcOEt 3:7) to obtain alcohol 48 as a white solid (24.4 mg, 63%). [α]²⁰

To a solution of sulfur (102.7 mg, 3.21 mmol) in a mixture of dry

AcOEt/diethyl ether (1:1, 25 mL) was added dimethyl phosphite

(300 μL, 3.21 mmol). The resulting mixture was cooled to 0 °C, and

triethylamine (450 mL, 3.23 mmol) was added dropwise over 1 min.

The mixture was stirred and allowed to reach room temperature over-

night. Then, the solvent of the reaction mixture was removed under

reduced pressure to give triethylammonium O,O-dimethyl phosphor-

D

+8.5 (c 1.06, CHCl₃). IR (ﬁlm): ν = 3360, 3299, 2952, 2916, 2849, 1649,

1541, 1466−1419, 1237, 1070, 1031 cm⁻¹. ¹H NMR (500 MHz,

CDCl₃) δ 6.82 (d, J = 7.4 Hz, 1H (NH)), 4.25 (br s, 1H (OH)), 4.23−

4.17 (m, 1H (CH−N)), 3.80 (d, J = 12.7 Hz, 6H (2CH₃−OPO−S)),

3.62−3.55 (m, 2H (2CH−O)), 3.32−3.17 (m, 2H (CH₂−S)), 3.06 (br

s, 1H (OH)), 2.22 (t, J = 7.5 Hz, 2H (CH₂−CO)), 1.70−1.59 (m, 3H),

1.55−1.47 (m, 1H), 1.45−1.37 (m, 1H), 1.33−1.23 (m, 31H), 0.87 (t,

J = 6.6 Hz, 6H (2CH₃)). ¹³C NMR (101 MHz, CDCl₃) δ 174.8 (CO),

75.9 (CH−O), 73.0 (CH−O), 54.6 (d, J_C−P= 6.7 Hz, 2CH₃−OPO−S),

53.6 (br s, CH−N), 36.8 (CH₂−CO), 33.2 (CH₂), 32.1 (CH₂), 31.9

(CH₂), 31.3 (d, J_C−P= 3.1 Hz, CH₂−S), 29.9 (CH₂), 29.8 (CH₂), 29.5

(CH₂), 29.4 (CH₂), 29.2 (CH₂), 26.1 (CH₂), 25.9 (CH₂), 22.8 (CH₂),

22.8 (CH₂), 14.3 (CH₃), 14.2 (CH₃). ³¹P NMR (121 MHz, CDCl₃) δ

33.67. HRMS (ESI-TOF) m/z: [M + H]⁺calcd for C₂₈H₅₉NO₆SP,

568.3801; found, 568.3823. Mp: 71−73 °C.

1

othioate (44) as a colorless oil (696 mg, 89%). H NMR (300 MHz,

CDCl₃) δ 12.18 (br s, 1H), 3.74 (d, J = 11.9 Hz, 1H), 3.59 (d, J =

12.8 Hz, 5H), 3.15−3.02 (m, 6H), 1.29 (t, J = 7.3 Hz, 9H). ³¹P NMR

(121 MHz, CDCl₃) δ 61.35. Then, to a solution of triethylammonium

O,O-dimethyl phosphorothioate (150 mg, 0.62 mmol) in dry diethyl

ether (5 mL) was added 1 M aq HCl (7 mL) dropwise over 5 min. The

reaction mixture was stirred at room temperature for 3 h. Then, water

(15 mL) was added, and the aqueous layer was extracted with diethyl

ether (3 × 15 mL). The collected organic layers were dried over MgSO₄

and ﬁltered, and the solvent was removed under reduced pressure to give

O,O-dimethyl S-hydrogen phosphorothioate (47) as a brown oil (60

mg, 68%). ¹H NMR (300 MHz, CDCl₃) δ 6.76 (br s, 1H), 3.85 (d, J =

12.8 Hz, 1H), 3.78 (d, J = 13.5 Hz, 5H). ³¹P NMR (121 MHz, CDCl₃) δ

63.47.

Benzyl ((2R,3S,4R)-3,4-Isopropylidenedioxy-1-

((dimethoxyphosphoryl)thio)octadecan-2-yl)carbamate (46b).

Method A. To a solution of triethylammonium O,O-dimethyl

phosphorothioate (44) (18.1 mg, 0.075 mmol) in dry THF (4 mL)

was added a solution of 4 (25.0 mg, 0.054 mmol) in dry THF (4 mL).

The resulting mixture was heated to 75 °C and stirred for 3 days. Then,

the crude was diluted with AcOEt (15 mL), and the organic layer was

washed with satd aq NaHCO₃(3 × 15 mL). Then, the organic layer

was dried over MgSO₄and ﬁltered, and the solvent was removed

in vacuo to give a crude that was puriﬁed by ﬂash chromatography (silica

gel, hexane/AcOEt 6:4) to aﬀord ring-opened product 46a as a colorless

oil (7.0 mg, 21%).

To a solution of O,O-dimethyl S-hydrogen phosphorothioate (47, for its

preparation see 46a) (41.4 mg, 0.29 mmol) in dry THF (4 mL) was

added a solution of 5 (106.2 mg, 0.22 mmol) in dry THF (2 mL). The

resulting mixture was heated to 80 °C and stirred overnight. Then, the

reaction mixture was allowed to reach room temperature, and additional

solution of O,O-dimethyl S-hydrogen phosphorothioate (47, 41.4 mg,

0.29 mmol) in dry THF (2 mL) was added. The resulting solution was

heated to 80 °C and stirred for 24 h. Next, the mixture was diluted with

AcOEt (30 mL,) and the organic layer was washed with satd aq

NaHCO₃(3 × 30 mL). Then, the organic layer was dried over MgSO₄

and ﬁltered, and the solvent was removed in vacuo to give a crude that

was puriﬁed by ﬂash chromatography (silica gel, hexane/AcOEt 7:3) to

Method B. To a solution of O,O-dimethyl S-hydrogen phosphor-

othioate (47) (10.7 mg, 0.075 mmol) in dry THF (4 mL) was added a

solution of 4 (26.7 mg, 0.057 mmol) in dry THF (4 mL). The resulting

mixture was heated to 75 °C and stirred overnight. Then, the crude was

diluted with AcOEt (15 mL), and the organic layer was washed with

satd aq NaHCO₃(3 × 15 mL). Then, the organic layer was dried over

MgSO₄and ﬁltered, and the solvent was removed in vacuo to give a crude

that was puriﬁed by ﬂash chromatography (silica gel, hexane/AcOEt

6:4) to aﬀord ring-opened product 46a as a colorless oil (23.3 mg, 67%).

aﬀord ring-opened product 46b as a white solid (67.4 mg, 49%). [α]²⁰

D

−8.1 (c 1.02, CHCl₃). IR (ﬁlm): ν = 3286, 2925, 2853, 1724, 1701, 1541,

1456, 1295, 1243, 1027 cm^{−1 1}H NMR (400 MHz, CDCl₃) δ 7.38−7.25

(m, 5H_ar), 5.40 (d, J = 9.0 Hz, 1H (NH)), 5.10 (s, 2H (CH₂benz)),

4.17−4.09 (m, 1H (CH−O (4))), 4.09−4.03 (t, J =6.4 Hz, 1H (CH−O

(3))), 4.03−3.94 (m, 1H (CH−N)), 3.75 (d, J = 12.7 Hz, 3H (CH₃−

O)), 3.69 (d, J = 12.6 Hz, 3H (CH₃−O)), 3.20 (td, A part of an AB

system, J_AB= 14.5 Hz, J = 3.0 Hz, 1H (CH₂−S)), 3.10−2.97 (m, B part of

an AB system, 1H (CH₂−S)), 1.60−1.46 (m, 3H), 1.42 (s, 3H (CH₃)),

1.36−1.17 (m, 23H), 1.31 (s, 3H (CH₃)), 0.87 (t, J = 6.8 Hz, 3H

(CH₃)). ¹³C NMR (101 MHz, CDCl₃) δ 155.9 (CO), 136.5 (C_ar),

128.6 (CH_ar), 128.3 (CH_ar), 128.2 (CH_ar), 108.3 (C), 78.3 (CH−O

(3)), 77.7 (CH−O (4)), 67.9 (CH₂benz), 54.1 (d, J_C−P= 6.1 Hz, CH₃−

OPO−S), 54.1 (d, J_C−P= 6.2 Hz, CH₃−OPO−S), 51.2 (d, J_C−P= 3.1 Hz,

CH−N), 33.6 (d, J_C−P= 3.6 Hz, CH₂−S), 32.0 (CH₂), 29.8 (3CH₂),

29.7 (2CH₂), 29.6 (CH₂), 29.5 (CH₂), 29.1 (CH₂), 27.7 (CH₃), 26.7

(CH₂), 25.6 (CH₃), 22.80 (CH₂), 14.23 (CH₃). ³¹P NMR (162 MHz,

CDCl₃) δ 32.36. HRMS (ESI-TOF) m/z: [M + Na]⁺calcd for

C₃₁H₅₄NO₇NaSP, 638.3256; found, 638.3278. Mp: 54−56 °C.

[α]²⁰−5.0 (c 1.01, CHCl₃). IR (ﬁlm): ν = 3288, 3066, 2924, 2853,

D

1682, 1648, 1541, 1458, 1244, 1024 cm⁻¹. ¹H NMR (500 MHz, CDCl₃)

δ 6.32 (d, J = 9.0 Hz, 1H (NH)), 4.31−4.24 (m, 1H (CH−N)), 4.16−

4.10 (m, 2H (2CH−O)), 3.80 (d, J = 12.5 Hz, 3H (CH₃−OPO−S)),

3.77 (d, J = 11.8 Hz, 3H (CH₃−OPO−S)), 3.18−3.00 (m, 2H (CH₂−

S)), 2.25−2.14 (m, 2H (CH₂−CO)), 1.65−1.58 (m, 2H), 1.58−1.49

(m, 3H), 1.43 (s, 3H (CH₃)), 1.32 (s, 3H (CH₃)), 1.31−1.23 (m, 31H),

0.89−0.85 (m, 6H (2CH₃)). ¹³C NMR (101 MHz, CDCl₃) δ 173.3

(CO), 108.2 (C), 78.3 (CH−O), 77.7 (CH−O), 54.5 (d, J_C−P= 6.6

Hz, CH₃−OPO−S), 54.3 (d, J_C−P= 6.5 Hz, CH₃−OPO−S), 49.2 (d,

J_C−P= 2.1 Hz, CH−N), 36.8 (CH₂−CO), 33.04 (d, J_C−P= 3.5 Hz, CH₂−

S), 32.1 (CH₂), 31.8 (CH₂), 29.8 (CH₂), 29.7 (3CH₂), 29.5 (CH₂), 29.4

(CH₂), 29.3 (CH₂), 29.2 (CH₂), 27.6 (CH₃), 26.8 (CH₂), 25.7 (CH₂),

25.5 (CH₃), 22.8 (CH₂), 22.8 (CH₂), 14.3 (CH₃), 14.2 (CH₃). ³¹P

3018

dx.doi.org/10.1021/jo500061w | J. Org. Chem. 2014, 79, 2993−3029

The Journal of Organic Chemistry

Article

Dibenzyl ((2S,3S,4R)-3,4-Isopropylidenedioxy-2-octanami-

To a solution of product 51a (135.0 mg, 0.181 mmol) in dry MeOH

(28 mL) was added CSA (69.0 mg, 0.30 mmol). The resulting mixture

was stirred at room temperature overnight. Then, the solvent of the

reaction mixture was removed under reduced pressure to give a crude

that was puriﬁed by ﬂash chromatography (silica gel, hexane/AcOEt

3:7) to get diol 53a as a white solid (102.0 mg, 80%). [α]²⁰_D+4.4 (c 1.01,

CHCl₃). IR (ﬁlm): ν = 3309, 3091, 3061, 2956, 2924, 2854, 1652, 1538,

1256, 1021 cm⁻¹. ¹H NMR (500 MHz, CDCl₃) δ 7.39−7.31 (m, 10H_ar),

6.30 (d, J = 8.4 Hz, 1H (NH)), 5.07−4.98 (m, 4H (2CH₂benz)), 4.42

(td, J = 10.6, 4.8 Hz, 1H), 4.16−4.09 (m, 1H), 4.04 (ddd,, J = 10.5, 8.8,

2.9 Hz, 1H), 3.54 (d, J = 6.8 Hz, 2H), 2.64 (br s, 2OH), 2.10 (td, J = 7.5,

1.5 Hz, 2H), 1.62−1.52 (m, 2H), 1.52−1.44 (m, 1H), 1.44−1.33 (m,

1H), 1.33−1.21 (m, 32H), 0.87 (t, J = 6.8 Hz, 3H (CH₃)), 0.86 (t, J =

7.0 Hz, 3H (CH₃)). ¹³C NMR (101 MHz, CDCl₃) δ 174.1 (CO),

135.5 (d, J_C−P= 6.4 Hz, C_ar), 135.5 (d, J_C−P= 6.5 Hz, C_ar), 129.0 (CH_ar),

128.8 (CH_ar), 128.2 (2CH_ar), 73.6 (CH−O), 72.8 (CH−O), 70.0

(d, J_C−P= 5.8 Hz, CH₂benz), 70.0 (d, J_C−P= 5.7 Hz, CH₂benz), 68.0 (d,

J_C−P= 6.0 Hz, CH₂−O (1)), 51.7 (d, J_C−P= 4.8 Hz, CH−N), 36.7

(CH₂), 32.3 (CH₂), 32.1 (CH₂), 31.8 (CH₂), 29.9 (CH₂), 29.8 (CH₂),

29.5 (CH₂), 29.4 (CH₂), 29.2 (CH₂), 26.1 (CH₂), 25.8 (CH₂), 22.8

(2CH₂), 14.3 (CH₃), 14.2 (CH₃). ³¹P NMR (162 MHz, CDCl₃) δ 0.93.

HRMS (ESI-TOF) m/z: [M + H]⁺calcd for C₄₀H₆₇NO₇P, 704.4655;

found, 704.4686. Mp: 67−69 °C.

dooctadecyl) Phosphate (51a).

Method A. To a solution of aziridine 4 (252.0 mg, 0.54 mmol) in dry

DCM (35 mL) was added dibenzyl phosphate (50) (197.6 mg,

0.70 mmol). The resulting mixture was stirred at room temperature for

3 days. Then, the reaction mixture was diluted with DCM (20 mL), the

organic layer was washed with satd aq NaHCO₃(3 × 30 mL), dried over

Na₂SO₄, and ﬁltered, and the solvent was removed under reduced pres-

sure to give a crude product which was puriﬁed by ﬂash chroma-

tography (silica gel, hexane/AcOEt 7:3) to give adduct 51a as a pale

yellow oil (253.0 mg, 63%).

Method B. To a solution of aziridine 4 (82.0 mg, 0.18 mmol) in dry

DCM (15 mL) was added dibenzyl phosphate (100 mg, 0.36 mmol).

The resulting mixture was heated to reﬂux and stirred overnight. Then,

the reaction mixture was diluted with DCM (15 mL), the organic layer

was washed with satd aq NaHCO₃(3 × 30 mL), dried over Na₂SO₄, and

ﬁltered, and the solvent was removed under reduced pressure to give a

crude product that was puriﬁed by ﬂash chromatography (silica gel,

hexane/AcOEt 1:0 to 3:7, gradient) to give adduct 51a as a pale yellow

oil (66.0 mg, 50%). Compounds 52 was isolated as reaction byproduct

in this reaction.

(2S,3S,4R)-3,4-Dihydroxy-2-octanamidooctadecyl Dihydro-

gen Phosphate (54a).

Data for Compound 51a. [α]²⁰+10.2 (c 1.072, CHCl₃). IR

D

(ﬁlm): ν = 3296, 3067, 2955, 2925, 2854, 1676, 1652, 1545, 1266,

1020 cm⁻¹. ¹H NMR (500 MHz, CDCl₃) δ 7.39−7.30 (m, 10H_ar), 5.84

(d, J = 9.4 Hz, 1H (NH)), 5.09−4.98 (m, 4H (2CH₂benz)), 4.31−4.25

(m, A part of an AB system, 1H (CH₂−O (1)), 4.25−4.19 (m, 1H

(CH−N)), 4.09−4.04 (m, 2H (CH−O and B part of a CH₂−O (1) AB

system)), 4.01 (dd, J = 8.6, 5.6 Hz, 1H (CH−O)), 2.12−2.00 (m, 2H

(CH₂−CO)), 1.60−1.52 (m, 2H), 1.52−1.45 (m, 2H), 1.45−1.38 (m,

1H), 1.37 (s, 3H (CH₃)), 1.32−1.27 (m, 3H), 1.29 (s, 3H (CH₃)),

1.27−1.20 (m, 28H), 0.87 (t, J = 7.0 Hz, 3H (CH₃)), 0.86 (t, J = 7.0 Hz,

3H (CH₃)). ¹³C NMR (101 MHz, CDCl₃) δ 172.8 (CO), 135.8 (d,

J_C−P= 6.7 Hz, C_ar), 135.6 (d, J_C−P= 6.7 Hz, C_ar), 128.8 (CH_ar), 128.7

(CH_ar), 128.0 (CH_ar), 128.0 (CH_ar) 108.2 (C), 77.7 (CH−O), 75.5

(CH−O), 69.6 (d, J_C−P= 5.6 Hz, CH₂benz), 69.5 (d, J_C−P= 5.5 Hz, CH₂

benz), 68.5 (d, J_C−P= 6.2 Hz, CH₂−O (1)), 48.2 (d, J_C−P= 6.1 Hz, CH−

N), 36.9 (CH₂−CO), 32.1 (CH₂), 31.8 (CH₂), 29.9 (CH₂), 29.8

(4CH₂), 29.7 (CH₂), 29.5 (CH₂), 29.4 (CH₂), 29.2 (CH₂), 29.1 (CH₂),

28.1 (CH₃), 26.7 (CH₂), 25.8 (CH₃), 25.7 (CH₂), 22.8 (2CH₂), 14.3

(CH₃), 14.2 (CH₃). ³¹P NMR (162 MHz, CDCl₃) δ −0.15. HRMS

(ESI-TOF) m/z: [M + Na]⁺calcd for C₄₃H₇₀NO₇PNa, 766.4788;

found, 766.4814.

A continuous ﬂow hydrogenation was performed eluting a solution of

diol 53a (56.1 mg, 0.080 mmol) in dry MeOH (1.6 mL) at room tem-

perature and 1 atm at a ﬂow rate of 1.0 mL/min. A 10% Pd/C catalyst

cartridge was used throughout. Then, the solvent of the collected reac-

tion mixture was removed under reduced pressure to give pure phos-

phate 54a as a white solid (30.8 mg, 74%). [α]²⁰_D+19.1 (c 1.12, MeOH).

IR (ﬁlm): ν = 3446, 3321, 2955, 2922, 2850, 1636, 1570 −1539, 1470

1

−1410, 1332 cm⁻¹. H NMR (400 MHz, CD₃OD) δ 4.22−4.16 (m,

1H), 4.16−4.11 (m, 2H), 3.64 (dd, J = 6.7, 5.2 Hz, 1H), 3.55−3.50 (m,

1H), 2.22 (t, J = 7.5 Hz, 2H (CH₂−CO)), 1.66−1.52 (m, 4H), 1.47−

1.38 (m, 1H), 1.38−1.25 (m, 33H), 0.91 (t, J = 7.1 Hz, 3H (CH₃)), 0.90

(t, J = 7.0 Hz, 3H (CH₃)). ¹³C NMR (101 MHz, CD₃OD) δ 176.1 (C

O), 74.8 (CH−O), 72.9 (CH−O), 66.5 (d, J_C−P= 5.2 Hz, CH₂−O (1)),

52.4 (d, J_C−P= 7.6 Hz, CH−N), 37.2 (CH₂), 33.1 (CH₂), 33.0 (CH₂),

32.4 (CH₂), 30.9 (CH₂), 30.8 (2CH₂), 30.5 (CH₂), 30.4 (CH₂), 30.3

(CH₂), 27.1 (2CH₂), 23.8 (CH₂), 14.5 (CH₃). ³¹P NMR (162 MHz,

CDCl₃) δ 1.74. HRMS (ESI-TOF) m/z: [M + H]⁺calcd for

C₂₆H₅₅NO₇P, 524.3716; found, 524.3701. Mp: 84−86 °C.

(2S,3S,4R)-1-Hydroxy-3,4-isopropylidenedioxy-2-octanami-

dooctadecane (52).

Benzyl ((2S,3S,4R)-1-((Bis(benzyloxy)phosphoryl)oxy)-3,4-

isopropylidenedioxy-octadecan-2-yl)carbamate (51b).

¹H NMR (400 MHz, CDCl₃) δ 6.00 (d, J = 8.4 Hz, 1H), 4.22−4.05 (m,

3H), 3.88 (dd, J = 11.4, 3.1 Hz, 2H), 3.68 (dd, J = 11.4, 3.4 Hz, 2H),

2.24−2.12 (m, 2H), 1.88 (br s, 2H), 1.67−1.51 (m, 4H), 1.47 (s, 3H),

1.34 (s, 3H), 1.43−1.17 (m, 30H), 0.87 (t, J = 6.7 Hz, 6H).

Dibenzyl ((2S,3S,4R)-3,4-Dihydroxy-2-octanamidooctadecyl)

Phosphate (53a).

To a solution of aziridine derivative 5 (169.0 mg, 0.36 mmol) in dry 1,2-

dichloroethane (25 mL) was added dibenzyl phosphate (50) (130.0 mg,

0.46 mmol). The resulting mixture was heated to 80 °C and stirred for

48 h. Then, the reaction mixture was diluted with DCM (25 mL), and

the organic layer was washed with satd aq NaHCO₃(3 × 30 mL). The

collected organic layers were dried over Na₂SO₄and ﬁltered, and the

solvent was removed under reduced pressure to give a crude that was

puriﬁed by ﬂash chromatography (silica gel, hexane/AcOEt 7:3) to give

adduct 51b as a pale yellow oil (195.0 mg, 72%). [α]²⁰_D+16.1 (c 1.02,

CHCl₃). IR (ﬁlm): ν = 3282, 3066, 3034, 2975, 2925, 2886, 1724,

1700−1490, 1386, 1300−1200, 1100−950 cm⁻¹. ¹H NMR (500 MHz,

CDCl₃) δ 7.37−7.27 (m, 15H_ar), 5.12 (d, A part of an AB system,

3019

dx.doi.org/10.1021/jo500061w | J. Org. Chem. 2014, 79, 2993−3029

The Journal of Organic Chemistry

Article

J_AB= 12.2 Hz, 1H (CH₂−O−CO)), 5.06−4.98 (m, 6H (2CH₂−O−P, B

part of a CH₂−O−CO AB system and NH)), 4.30−4.23 (m, A part of an

AB system, 1H (CH₂−O (1))), 4.14−4.09 (m, B part of an AB system,

1H (CH₂−O (1))), 4.08−4.02 (m, 1H (CH−O)), 3.97−3.87 (m, 2H

(CH−O and CH−N)), 1.56−1.41 (m, 3H), 1.36 (s, 3H (CH₃)), 1.32−

1.23 (m, 26H), 0.88 (t, J = 6.9 Hz, 3H (CH₃)). ¹³C NMR (101 MHz,

³¹P NMR (121 MHz, CDCl₃) δ 1.12. HRMS (ESI-TOF) m/z: [M-H]⁻

calcd for C₁₈H₃₉NO₆P, 396.2515; found, 396.2498. Mp: 169−170 °C.

This product was not further characterized because of its low solubility.

Synthesis of 1-Amino-(phyto)sphingolipid Analogues. Gen-

eral Procedure 3: Nucleophilic Ring-Opening Reaction of Acylated

Aziridine Derivatives with Amines. A solution of aziridine derivative in

dry acetonitrile (MeCN), was treated with lithium perchlorate for

30 min. Then, amine was added, and the resulting mixture was heated to

80 °C and stirred overnight. The reaction mixture was allowed to reach

room temperature and diluted with diethyl ether, and the organic layer

was washed with water. Then, the organic layer was dried over MgSO₄

and ﬁltered, and the solvent was removed in vacuo to give a crude

product, which was puriﬁed by ﬂash chromatography on silica gel to

aﬀord ring-opened products.

General Procedure 4: Diol Deprotection Reaction of 1-Amino

Adducts. To a solution of ring-opened product in MeOH was added

CSA. The resulting mixture was stirred at room temperature overnight.

Then the reaction mixture was neutralized with TEA, and after that, the

solvent was removed in vacuo to give the crude product, which was

puriﬁed by ﬂash chromatography on silica gel to aﬀord diols.

N-((2S,3S,4R)-1-(Heptylamino)-3,4-isopropylidenedioxyocta-

decan-2-yl)octanamide (55a).

CDCl₃) δ 155.5 (CO), 136.4 (C_ar−CH₂−O−CO), 135.9 (d, J_C−P

=

6.8 Hz, C_ar−CH₂−O−P), 135.8 (d, J_C−P= 7.0 Hz, C_ar−CH₂−O−P),

128.7 (CH_ar), 128.7 (CH_ar), 128.7 (CH_ar), 128.6 (CH_ar), 128.3 (CH_ar),

128.1 (CH_ar), 128.0 (CH_ar), 128.0 (CH_ar), 108.2 (C), 77.7 (CH−O),

75.5 (CH−O), 69.5 (d, J_C−P= 5.7 Hz, CH₂−O−P), 69.4 (d, J_C−P

=

5.7 Hz, CH₂−O−P), 68.2 (d, J_C−P= 6.0 Hz, CH₂−O (1)), 67.0 (CH₂−

O−CO), 50.4 (d, J_C−P= 7.2 Hz, CH−N), 32.1 (CH₂), 29.8 (2CH₂),

29.7 (3CH₂), 29.5 (CH₂), 28.9 (CH₂), 28.1 (CH₃), 26.6 (CH₂), 25.8

(CH₃), 22.8 (CH₂), 14.3 (CH₃). ³¹P NMR (162 MHz, CDCl₃) δ −0.31.

HRMS (ESI-TOF) m/z: [M + H]⁺calcd for C₄₃H₆₃NO₈P, 752.4291;

found, 752.4288.

Benzyl ((2S,3S,4R)-1-((Bis(benzyloxy)phosphoryl)oxy)-3,4-di-

hydroxyoctadecan-2-yl)carbamate (53b).

To a solution of carbamate 51b (109 mg, 0.14 mmol) in dry MeOH

(22 mL) was added CSA until pH 2 was reached. The resulting mixture

was stirred at room temperature overnight. Then, the solvent of the

reaction mixture was removed under reduced pressure to give a crude

that was puriﬁed by ﬂash chromatography (silica gel, hexane/AcOEt

1:1) to get diol 53b as a colorless oil (88.0 mg, 85%). [α]²⁰_D+20.6 (c

1.056, CHCl₃). IR (ﬁlm): ν = 3396−3262, 3062, 3034, 2920, 2852,

Octanamide 55a was synthesized from 4 (52.7 mg, 0.11 mmol), lithium

perchlorate (96.3 mg, 0.90 mmol), and n-heptylamine (51 μL,

0.34 mmol) in dry MeCN (2 mL), according to General Procedure 3.

After ﬂash chromatographic puriﬁcation (silica gel, hexane/AcOEt 6:4 +

1% aq NH₃), pure product 55a was isolated as a colorless oil (61.5 mg,

1

1711, 1691, 1541, 1246, 1017 cm⁻¹. H NMR (400 MHz, CDCl₃) δ

7.40−7.28 (m, 15H_ar), 5.17 (d, J = 8.9 Hz, 1H (NH)), 5.12−4.95 (m, 6H

(3CH₂benz)), 4.39 (td, A part of an AB sytem, J_AB= 10.6 Hz, J = 3.7 Hz,

1H (CH₂−O (1))), 4.04 (td, B part of an AB system, J_AB= 10.6 Hz, J =

2.8 Hz, 1H (CH₂−O (1))), 3.91−3.82 (m, 1H (CH−N)), 3.61−3.54

(m, 1H (CH−O (4))), 3.54−3.47 (m, 1H (CH−O (3))), 1.90 (br s, 2H

(2OH)), 1.60−1.19 (m, 26H), 0.88 (t, J = 6.8 Hz, 3H (CH₃)). ¹³C NMR

(101 MHz, CDCl₃) δ 156.3 (CO), 136.4 (C_ar−CH₂−O−CO), 135.5

(d, J_C−P= 6.2 Hz, C_ar−CH₂−O−P), 135.5 (d, J_C−P= 6.6 Hz, C_ar−CH₂−

O−P), 128.9 (CH_ar), 128.8 (CH_ar), 128.6 (CH_ar), 128.3 (CH_ar), 128.2

(CH_ar), 128.1 (CH_ar), 73.6 (CH−O (3)), 72.5 (CH−O (4)), 69.9 (d,

J_C−P= 5.6 Hz, 2CH₂−O−P), 67.4 (d, J_C−P= 5.7 Hz, CH₂−O (1)), 67.0

(CH₂−O−CO), 52.6 (d, J_C−P= 5.2 Hz, CH−N), 32.1 (CH₂), 31.9

(CH₂), 29.9 (CH₂), 29.8 (CH₂), 29.5 (CH₂), 26.1 (CH₂), 22.8 (CH₂),

14.3 (CH₃). ³¹P NMR (162 MHz, CDCl₃) δ 0.78. HRMS (ESI-TOF)

m/z: [M + H]⁺calcd for C₄₀H₅₉NO₈P, 712.3978; found, 712.3966.

(2S,3S,4R)-2-Amino-3,4-dihydroxyoctadecyl Dihydrogen

Phosphate (54b).

93%). [α]²⁰+7.1 (c 1.09, CHCl₃). IR (ﬁlm): ν = 3275, 3069, 2955,

D

2925, 2854, 1642, 1552, 1466, 1378−1363, 1219 cm⁻¹. ¹H NMR

(400 MHz, CDCl₃) δ 6.38 (d, J = 8.0 Hz, 1H (NH−CO)), 4.18−4.06

(m, 3H (2CH−O and CH−N)), 2.95 (dd, A part of an AB system, J_AB

=

12.4 Hz, J = 4.7 Hz, 1H (CH₂−N (1)), 2.65 (dd, B part of an AB system,

J_AB= 12.4 Hz, J = 3.5 Hz, 1H (CH₂−N (1)), 2.60 (t, J = 7.0 Hz, 2H

(CH₂−N (heptylamino))), 2.31 - 2.21 (m, 1H (NH)), 2.17 (t, J =

7.6 Hz, 2H (CH₂−CO)), 1.63−1.58 (m, 2H), 1.57−1.52 (m, 2H),

1.50−1.44 (m, 2H), 1.43 (s, 3H (CH₃)), 1.33−1.22 (m, 40H), 1.32 (s,

3H (CH₃)), 0.89−0.85 (m, 9H (3CH₃)). ¹³C NMR (101 MHz, CDCl₃)

δ 173.0 (CO), 108.0 (C), 78.4 (CH−O), 78.0 (CH−O), 50.5 (CH₂−

N (1)), 50.1 (CH₂−N (heptylamino)), 47.8 (CH−N), 37.1 (CH₂−

CO), 32.1 (CH₂), 32.0 (CH₂), 31.9 (CH₂), 29.9 (CH₂), 29.8 (2CH₂),

29.7 (CH₂), 29.5 (CH₂), 29.4 (CH₂), 29.3 (CH₂), 29.2 (CH₂), 27.7

(CH₃), 27.3 (CH₂), 26.9 (CH₂), 25.9 (CH₂), 25.5 (CH₃), 22.8 (CH₂),

22.8 (CH₂), 14.3 (CH₃), 14.2 (CH₃). HRMS (ESI-TOF) m/z:

[M + H]⁺calcd for C₃₆H₇₃N₂O₃, 581.5621; found, 581.5594.

N-((2S,3S,4R)-1-(Heptylamino)-3,4-dihydroxyoctadecan-2-

yl)octanamide (56a).

To a solution of benzyl carbamate 53b (48.7 mg, 0.068 mmol) in MeOH

(4 mL) was added Pd/C (34.7 mg, 5−15% Pd on activated C, water-

wet). The ﬂask was repeatedly ﬁlled and evacuated with H₂, and the

mixture was vigorously stirred at room temperature for 3.5 h under H₂

(1 atm). After this period, the reaction mixture was ﬁltered through a

plug of Celite, and the ﬁltrand was washed with MeOH (3 × 10 mL).

Then, the ﬁltrate was concentrated in vacuo to give reduced phosphate

Diol 56a was synthesized from 55a (21.2 mg, 0.037 mmol) and CSA

(17.0 mg, 0.073 mmol) in MeOH (2 mL), according to General

Procedure 4. After ﬂash chromatographic puriﬁcation (silica gel, DCM/

MeOH 9.9:0.1 + 1% aq NH₃), pure product 56a was isolated as a pale

1

54b as a white solid (19.6 mg, 72%). H NMR (500 MHz, CD₃OD/

TFA, 1:1) δ 4.43−4.35 (m, A part of an AB system, 1H (CH₂−O)),

4.28−4.20 (m, B part of an AB system, 1H (CH₂−O)), 3.76−3.69 (m,

1H (CH−N)), 3.65−3.60 (m, 1H (CH−O (3)), 3.55−3.48 (m, 1H

(CH−O (4)), 1.86−1.72 (m, 1H), 1.60−1.50 (m, 1H), 1.43−1.21 (m,

24H), 0.84 (t, J = 6.2 Hz, 3H (CH₃)). ¹³C NMR (101 MHz, CD₃OD/

yellow oil (13.1 mg, 66%). [α]²⁰+15.1 (c 1.20, CHCl₃). IR (ﬁlm):

D

1

ν = 3294, 2958, 2923, 2853, 1668, 1641, 1542, 1466 cm⁻¹. H NMR

(500 MHz, CDCl₃) δ 6.90 (br s, 1H (NH−CO)), 4.23−4.16 (m, 1H

(CH−N)), 3.68−3.60 (m, 3H (2CH−O and NH)), 3.00−2.91 (m,

2H (CH₂−N (1))), 2.81−2.74 (m, A part of an AB system, 1H (CH₂−N

(heptylamino))), 2.74−2.67 (m, B part of an AB system, 1H (CH₂−N

(heptylamino))), 2.21 (t, J = 7.6 Hz, 2H (CH₂−CO)), 1.65−1.56

TFA, 1:1) δ 73.9 (CH−O (4)), 72.9 (CH−O (3)), 64.3 (d, J_C−P

=

4.1 Hz, CH₂−O), 55.5 (d, J_C−P= 6.8 Hz, CH−N), 35.4 (CH₂), 33.1

(CH₂), 30.8 (CH₂), 30.5 (CH₂), 26.3 (CH₂), 23.7 (CH₂), 14.3 (CH₃).

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(m, 4H), 1.56−1.49 (m, 2H), 1.46−1.37 (m, 2H), 1.34−1.22 (m, 38H),

0.87 (t, J = 6.8 Hz, 9H (3CH₃)). ¹³C NMR (101 MHz, CDCl₃) δ 173.6

(CO), 75.7 (CH−O), 72.8 (CH−O), 49.4 (CH₂−N (heptylamino)),

48.9 (CH−N), 48.8 (CH₂−N (1)), 36.8 (CH₂−CO), 33.5 (CH₂), 32.1

(CH₂), 31.9 (CH₂), 31.8 (CH₂), 29.9 (CH₂), 29.8 (3CH₂) 29.5 (CH₂),

29.4 (CH₂), 29.2 (CH₂), 29.1 (CH₂), 28.3 (CH₂), 27.1 (CH₂), 26.3

(CH₂), 25.8 (CH₂), 22.8 (2CH₂), 22.7 (CH₂), 14.3 (CH₃), 14.2

(2CH₃). HRMS (ESI-TOF) m/z: [2M + H]⁺calcd for C₆₆H₁₃₇N₄O₆,

1082.0538; found, 1082.0527.

N-((2S,3S,4R)-1-(Dibutylamino)-3,4-isopropylidenedioxyoc-

tadecan-2-yl)octanamide (55c).

Octanamide 55c was synthesized from 4 (41.9 mg, 0.09 mmol), lithium

perchlorate (77.0 mg, 0.72 mmol), and dibutylamine (46 μL,

0.27 mmol) in dry MeCN (360 μL), according to General Procedure

3. After ﬂash chromatographic puriﬁcation (silica gel, hexane/AcOEt

8.5:1.5 + 1% aq NH₃), pure product 55c was isolated as a colorless oil

N-((2S,3S,4R)-3,4-Isopropylidenedioxy-1-(phenethylamino)-

octadecan-2-yl)octanamide (55b).

(52.3 mg, 98%). [α]²⁰−12.5 (c 1.10, CHCl₃). IR (ﬁlm): ν = 3294,

D

2955, 2925, 2855, 1641, 1545, 1465, 1377, 1364, 1050 cm⁻¹. ¹H NMR

(500 MHz, CDCl₃) δ 5.90 (br s, 1H (NH)), 4.29 (t, J = 5.8 Hz, 1H

(CH−O (3))), 4.16−4.10 (m, 1H (CH−O (4))), 4.00−3.92 (m, 1H

(CH−N)), 2.77−2.67 (m, A part of an AB system, 1H (CH₂−N (1))),

2.54−2.35 (m, 5H (B part of CH₂−N (1) AB system and 2CH₂−N

(dibutylamino))), 2.15 (t, J = 7.6 Hz, 2H (CH₂−CO)), 1.64−1.47 (m,

5H), 1.43 (s, 3H (CH₃)), 1.41−1.34 (m, 5H), 1.31 (s, 3H (CH₃)),

1.31−1.23 (m, 34H), 0.92−0.84 (m, 12H (4CH₃)). ¹³C NMR

(101 MHz, CDCl₃) δ 173.2 (CO), 107.8 (C), 77.8 (2CH−O),

54.4 (2CH₂−N (dibutylamino)), 54.0 (CH₂−N (1)), 48.0 (CH−N),

37.1 (CH₂−CO), 32.1 (CH₂), 31.9 (CH₂), 29.9 (CH₂), 29.8 (2CH₂),

29.7 (3CH₂), 29.5 (CH₂), 29.4 (CH₂), 29.2 (CH₂), 27.3 (CH₃), 26.7

(CH₂), 25.8 (CH₂), 25.5 (CH₃), 22.8 (2CH₂), 20.8 (CH₂), 14.3

(2CH₃), 14.2 (CH₃). HRMS (ESI-TOF) m/z: [M + H]⁺calcd for

C₃₇H₇₅N₂O₃, 595.5778; found, 595.5786.

Amide 55b was synthesized from 4 (111.0 mg, 0.24 mmol), lithium

perchlorate (203.0 mg, 1.91 mmol), and 2-phenylethylamine (91 μL,

0.72 mmol) in dry MeCN (4 mL), according to General Procedure 3.

After ﬂash chromatographic puriﬁcation (silica gel, hexane/AcOEt 7:3 +

1% aq NH₃), pure product 55b was isolated as a pale brown oil (95.0 mg,

68%). [α]²⁰+9.4 (c 1.48, CHCl₃). IR (ﬁlm): ν = 3294, 3063, 2952,

D

2924, 2851, 1641, 1549, 1468 - 1463, 1380 - 1367, 1246 - 1221 cm^−1.1H

NMR (400 MHz, CDCl₃) δ 7.32−7.25 (m, 2H_ar), 7.23−7.17 (m, 3H_ar),

6.37 (d, J = 8.7 Hz, 1H (NH−CO)), 4.16−4.08 (m, 2H (CH−N and

CH−O)), 4.04 (dd, J = 13.8, 7.3 Hz, 1H (CH−O)), 2.97 (dd, A part of

an AB system, J_AB= 12.4 Hz, J = 4.8 Hz, 1H (CH₂−N (1))), 2.93−2.87

(m, 2H (CH₂−N (phenethylamino)), 2.82−2.77 (m, 2H (CH₂−Ph)),

2.68 (dd, B part of an AB system, J_AB= 12.4 Hz, J = 3.6 Hz, 1H (CH₂−N

(1))), 2.59 (br s, 1H (NH)), 2.11 (t, J = 7.4 Hz, 2H (CH₂−CO)), 1.61−

1.55 (m, 2H), 1.54−1.47 (m, 3H), 1.34 (s, 3H (CH₃)), 1.32−1.21 (m,

34H), 0.87 (t, J = 6.7 Hz, 6H (2CH₃)). ¹³C NMR (101 MHz, CDCl₃) δ

173.0 (CO), 139.7 (C_ar), 128.9 (CH_ar), 128.6 (CH_ar), 126.4 (CH_ar),

107.9 (C), 78.3 (CH−O), 77.9 (CH−O), 51.3 (CH₂−N (phenethy-

lamino)), 50.5 (CH₂−N (1)), 47.7 (CH−N), 37.0 (CH₂−CO), 36.0

(CH₂−Ph), 32.1 (CH₂), 31.9 (CH₂), 29.8 (3CH₂), 29.7 (2CH₂), 29.5

(2CH₂), 29.4 (CH₂), 29.2 (CH₂), 27.6 (CH₃), 26.8 (CH₂), 25.9 (CH₂),

25.4 (CH₃), 22.8 (2CH₂), 14.3 (CH₃), 14.2 (CH₃). HRMS (ESI-TOF)

m/z: [M + H]⁺calcd for C₃₇H₆₇N₂O₃, 587.5152; found, 587.5172.

N-((2S,3S,4R)-3,4-Dihydroxy-1-(phenethylamino)octadecan-

2-yl)octanamide (56b).

N-((2S,3S,4R)-1-(Dibutylamino)-3,4-dihydroxyoctadecan-2-

yl)octanamide (56c).

Product 56c was synthesized from 55c (52.3 mg, 0.088 mmol) and CSA

(40.8 mg, 0.18 mmol) in MeOH (4 mL), according to General Pro-

cedure 4. After ﬂash chromatographic puriﬁcation (silica gel, hexane/

AcOEt 8:2 + 1% aq NH₃) pure alcohol 56c was isolated as a pale yellow

oil (31.3 mg, 64%). [α]²⁰_D+34.9 (c 1.41, CHCl₃). IR (ﬁlm): ν = 3306,

2961, 2924, 2854, 1637, 1542, 1460, 1074 cm⁻¹. ¹H NMR (500 MHz,

CDCl₃) δ 6.50 (br s, 1H (NH)), 4.26−4.17 (m, 1H (CH−N)), 3.69−

3.63 (m, 1H (CH−O (3))), 3.59−3.52 (m, 1H (CH−O (4))), 2.86 (dd,

A part of an AB system, J_AB= 12.5 Hz, J = 9.6 Hz, 1H (CH₂N (1))), 2.74

(td, 2H_Apart of an AB system, J_AB= 12.4 Hz, J = 5.2 Hz (2CH_AH_B−N

(dibutylamino))), 2.52−2.44 (m, 3H (B part of a CH₂−N (1) AB

system and 2H_Bpart of a CH_AH_B−N (dibutylamino) AB system)), 2.18

(t, J = 7.6 Hz, 2H (CH₂−CO)), 1.65−1.58 (m, 2H), 1.57−1.50 (m, 3H),

1.49−1.43 (m, 2H), 1.42−1.37 (m, 1H), 1.36−1.20 (m, 36H), 0.93 (t,

J = 7.3 Hz, 6H (2CH₃)), 0.88 (t, J = 6.9 Hz, 6H (2CH₃)). ¹³C NMR (101

MHz, CDCl₃) δ 173.0 (CO), 76.7 (CH−O (3)), 72.9 (CH−O (4)),

54.4 (CH₂−N (1)), 53.7 (2CH₂−N (dibutylamino)), 48.0 (CH−N),

36.8 (CH₂−CO), 33.9 (CH₂), 32.1 (CH₂), 31.8 (CH₂), 29.8 (3CH₂),

29.5 (CH₂), 29.4 (CH₂), 29.2 (CH₂), 27.8 (CH₂), 26.3 (CH₂), 25.8

(CH₂), 22.8 (CH₂), 22.8 (CH₂), 20.8 (CH₂), 14.3 (CH₃), 14.2 (CH₃),

14.1 (CH₃). HRMS (ESI-TOF) m/z: [M + H]⁺calcd for C₃₄H₇₁N₂O₃,

555.5465; found, 555.5469.

Alcohol 56b was synthesized from 55b (18.9 mg, 0.032 mmol) and CSA

(15.0 mg, 0.064 mmol) in MeOH (2 mL), according to General

Procedure 4. After ﬂash chromatographic puriﬁcation (silica gel, DCM/

MeOH 97.5:2.5 + 1% aq NH₃), pure diol 56b was isolated as a pale

yellow oil (10.5 mg, 60%). [α]²⁰+27.1 (c 1.02, CHCl₃). IR (ﬁlm):

D

1

ν = 3275, 2958, 2924, 2953, 1656, 1555, 1520, 1467, 1377 cm⁻¹. H

NMR (400 MHz, CDCl₃) δ 7.30 (t, J = 7.4 Hz, 2H_ar), 7.23 (t, J = 7.0 Hz,

1H_ar), 7.16 (d, J = 7.2 Hz, 2H_ar), 6.17 (d, J = 8.1 Hz, 1H (NH−CO)),

4.06 (br t, J = 8.3 Hz, 1H (CH−N)), 3.60−3.52 (m, 2H (2CH−O)),

2.96−2.68 (m, 6H (2CH₂−N and CH₂−Ph)), 2.14 (t, J = 7.6 Hz, 2H

(CH₂−CO)), 1.64−1.55 (m, 2H), 1.54−1.35 (m, 3H), 1.34−1.20 (m,

31H), 0.87 (m, 6H (2CH₃)). ¹³C NMR (101 MHz, CDCl₃) δ 172.8

(CO), 138.9 (C_ar), 128.9 (CH_ar), 128.8 (CH_ar), 126.8 (CH_ar), 76.1

(CH−O), 73.0 (CH−O), 50.5 (CH₂−N), 49.3 (CH−N), 48.3 (CH₂−

N), 36.9 (CH₂−CO), 35.8 (CH₂), 34.1 (CH₂−Ph), 32.1 (CH₂), 31.8

(CH₂), 29.9 (CH₂), 29.8 (CH₂), 29.5 (CH₂), 29.4 (CH₂), 29.2 (CH₂),

26.4 (CH₂), 25.9 (CH₂), 22.9 (CH₂), 22.8 (CH₂), 14.3 (CH₃), 14.2

(CH₃). HRMS (ESI-TOF) m/z: [M + H]⁺calcd for C₃₄H₆₃N₂O₃,

547.4839; found, 547.4855.

N-((2S,3S,4R)-3,4-Isopropylidenedioxy-1-(pyrrolidin-1-yl)-

octadecan-2-yl)octanamide (55d).

Product 55d was synthesized from 4 (52.7 mg, 0.11 mmol), lithium

perchlorate (96.3 mg, 0.91 mmol) and pyrrolidine (28 μL, 0.34 mmol)

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in dry MeCN (2 mL), according to General Procedure 3. In this case, the

reaction mixture was diluted with diethyl ether (2 mL), and the organic

layer was washed with water (3 × 2 mL). Then, the organic layer was

dried over MgSO₄and ﬁltered, and the volatiles were removed in vacuo

(c 1.08, CHCl₃). IR (ﬁlm): ν = 3291, 2958, 2924, 2853, 1642, 1546,

1454, 1300 - 1219, 1119 cm⁻¹. ¹H NMR (400 MHz, CDCl₃) δ 5.78 (br s,

1H (NH)), 4.20−4.10 (m, 3H (2CH−O and CH−N)), 3.72−3.60 (m,

4H (2CH₂−O)), 2.64−2.54 (m, 3H (A part of a CH₂−N (1) AB system

and 2H_Apart of a CH_AH_B−N (morpholino) AB system)), 2.50 (dd, B

part of an AB system, J_AB= 13.3 Hz, J = 2.2 Hz, 1H (CH₂−N (1))),

2.47−2.37 (m, 2H_Bpart of an AB system (2CH_AH_B−N (morpholi-

no))), 2.16 (t, J = 7.5 Hz, 2H (CH₂−CO)), 1.64−1.54 (m, 4H), 1.54−

1.47 (m, 1H), 1.42 (s, 3H (CH₃)), 1.32−1.21 (m, 31H), 1.30 (s, 3H

(CH₃)), 0.86 (t, J = 6.6 Hz, 6H (2CH₃)). ¹³C NMR (101 MHz, CDCl₃)

δ 173.0 (CO), 107.9 (C), 78.8 (CH−O), 77.8 (CH−O), 67.1

(2CH₂−O (morpholino)), 59.0 (CH₂−N (1)), 54.2 (2CH₂−N

(morpholino)), 46.7 (CH−N), 37.1 (CH₂−CO), 32.0 (CH₂), 31.8

(CH₂), 29.8 (2CH₂), 29.7 (3CH₂), 29.5 (2CH₂), 29.3 (CH₂),

29.2 (CH₂), 27.2 (CH₃), 26.8 (CH₂), 25.9 (CH₂), 25.4 (CH₃), 22.8

(2CH₂), 14.3 (CH₃), 14.2 (CH₃). HRMS (ESI-TOF) m/z: [M + H]⁺

calcd for C₃₃H₆₅N₂O₄, 553.4944; found, 553.4933.

to give adduct 55d as a colorless oil (57.8 mg, 98%). [α]²⁰−11.2 (c

D

1.06, CHCl₃). IR (ﬁlm): ν = 3284, 3076, 2955, 2924, 2854, 2775, 1642,

1558, 1458, 1219 cm⁻¹. ¹H NMR (500 MHz, CDCl₃) δ 6.03 (br d, J =

5.9 Hz, 1H (NH)), 4.21 (t, J = 5.7 Hz, 1H (CH−O (3))), 4.16−4.10 (m,

1H (CH−O (4)), 4.10−4.05 (m, 1H (CH−N)), 2.88 (dd, A part of an

AB system, J_AB= 12.9 Hz, J = 8.7 Hz, 1H (CH₂−N (1))), 2.69−2.62 (m,

2H_Apart of an AB system (2CH_AH_B−N (pyrrolidin))), 2.60−2.52 (m,

3H (B part of a CH₂−N (1) AB system and 2H_Bpart of a CH_AH_B−N

(pyrrolidin) AB system)), 2.23−2.12 (m, 2H (CH₂−CO)), 1.83−1.70

(m, 4H (2CH₂−CH₂−N (pyrrolidin))), 1.65−1.55 (m, 4H), 1.55−1.47

(m, 1H), 1.42 (s, 3H (CH₃)), 1.31 (s, 3H (CH₃)), 1.29−1.21 (m, 31H),

0.88−0.83 (m, 6H (2CH₃)). ¹³C NMR (101 MHz, CDCl₃) δ 173.3

(CO), 107.8 (C), 78.5 (CH−O (3)), 77.8 (CH−O (4)), 56.2 (CH₂−

N (1)), 55.0 (2CH₂−N (pyrrolidin)), 48.6 (CH−N), 37.0 (CH₂−CO),

32.0 (CH₂), 31.8 (CH₂), 29.8 (2CH₂), 29.7 (3CH₂), 29.5 (2CH₂), 29.3

(CH₂), 29.2 (CH₂), 27.3 (CH₃), 26.8 (CH₂), 25.8 (CH₂), 25.4 (CH₃),

23.7 (2CH₂), 22.8 (CH₂), 22.7 (CH₂), 14.2 (CH₃), 14.2 (CH₃). HRMS

(ESI-TOF) m/z: [2M + H]⁺calcd for C₆₆H₁₂₉N₄O₆, 1073.9912; found,

1073.9940.

N-((2S,3S,4R)-3,4-Dihydroxy-1-morpholinooctadecan-2-yl)-

octanamide (56e).

N-((2S,3S,4R)-3,4-Dihydroxy-1-(pyrrolidin-1-yl)octadecan-2-

yl)octanamide (56d).

Alcohol 56e was synthesized from 55e (44.3 mg, 0.08 mmol) and CSA

(37.2 mg, 0.16 mmol) in MeOH (4 mL), according to General

Procedure 4. After ﬂash chromatographic puriﬁcation (silica gel, DCM/

MeOH 9.7:0.3 + 1% aq NH₃) pure product 56e was isolated as a white

solid (28.0 mg, 68%). [α]²⁰_D+24.4 (c 1.02, CHCl₃). IR (ﬁlm): ν = 3303,

2955, 2916, 2849, 1637, 1542, 1465, 1454 cm⁻¹. ¹H NMR (400 MHz,

CDCl₃) δ 6.12 (d, J = 8.2 Hz, 1H (NH)), 4.27−4.19 (m, 1H (CH−N)),

3.77−3.64 (m, 4H (2CH₂−O (morpholino))), 3.64−3.61 (m, 1H

(CH−O (3))), 3.58−3.52 (m, 1H (CH−O (4))), 2.84−2.75 (m, 2H_A

part of an AB system (2CH_AH_B−N (morpholino))), 2.71 (dd, A part of

an AB system, J_AB= 12.7 Hz, J = 10.2 Hz, 1H (CH₂−N (1))), 2.55−2.46

(m, 2H_Bpart of an AB system (2CH_AH_B−N (morpholino))), 2.30 (dd,

B part of an AB system, J_AB= 12.7 Hz, J = 2.7 Hz, 1H (CH₂−N (1))),

2.19−2.13 (t, J = 7.6 Hz, 2H (CH₂−CO)), 1.65−1.57 (m, 2H), 1.57−

Diol 56d was synthesized from 55d (59.1 mg, 0.11 mmol) and CSA

(51.1 mg, 0.22 mmol) in MeOH (5 mL), according to General Pro-

cedure 4. After ﬂash chromatographic puriﬁcation (silica gel, DCM/

MeOH 9.5:0.5 + 1% aq NH₃) pure product 56d was isolated as a white

solid (45.4 mg, 83%). [α]²⁰_D+24.4 (c 1.00, CHCl₃). IR (ﬁlm): ν = 3417,

3349, 2958, 2922, 2852, 1639, 1559 - 1520, 1463, 1119−1024 cm⁻¹. ¹H

NMR (400 MHz, CDCl₃) δ 6.33 (d, J = 8.1 Hz, 1H (NH)), 4.18 (br t, J =

8.8 Hz, 1H (CH−N)), 3.64−3.60 (m, 1H (CH−O (3))), 3.59−3.52 (m,

1H (CH−O (4))), 2.97 (dd, A part of an AB system, J_AB= 12.4 Hz, J =

9.8 Hz, 1H (CH₂−N (1)), 2.82−2.74 (m, 2H_Apart of an AB system

(2CH_AH_B−N (pyrrolidin))), 2.74−2.63 (m, 2H_Bpart of an AB system

1.49 (m, 2H), 1.42−1.22 (m, 32H), 0.87 (t, J = 6.8 Hz, 6H (2CH₃)). ¹³

C

NMR (101 MHz, CDCl₃) δ 172.8 (CO), 76.2 (CH−O (3)), 73.0

(CH−O (4)), 66.5 (2CH₂−O (morpholino)), 57.6 (CH₂−N (1)), 53.9

(2CH₂−N (morpholino)), 46.9 (CH−N), 36.8 (CH₂−CO), 34.1

(CH₂), 32.1 (CH₂), 31.8 (CH₂), 29.8 (3CH₂), 29.7 (CH₂), 29.5 (CH₂),

29.4 (CH₂), 29.2 (CH₂), 26.2 (CH₂), 25.8 (CH₂), 22.8 (CH₂), 22.8

(CH₂), 14.3 (CH₃), 14.2 (CH₃). HRMS (ESI-TOF) m/z: [M + H]⁺

calcd for C₃₀H₆₁N₂O₄, 513.4631; found, 513.4644. Mp: 69−71 °C.

N-((2S,3S,4R)-1-(Bis(2-hydroxyethyl)amino)-3,4-isopropyli-

denedioxyoctadecan-2-yl)octanamide (55f).

(2CH_AH_B−N (pyrrolidin))), 2.40 (dd, B part of an AB system, J_AB

=

12.4 Hz, J = 3.2 Hz, 1H (CH₂−N (1))), 2.17 (t, J = 7.6 Hz, 2H (CH₂−

CO)), 1.86−1.75 (m, 4H (2CH₂−CH₂−N (pyrrolidin))), 1.65−1.55

(m, 2H), 1.55−1.46 (m, 2H), 1.43−1.19 (m, 32H), 0.87 (t, J = 5.5 Hz,

3H (CH₃)), 0.86 (t, J = 5.8 Hz, 3H (CH₃)). ¹³C NMR (101 MHz,

CDCl₃) δ 172.8 (CO), 76.4 (CH−O (3)), 73.0 (CH−O (4)), 54.9

(CH₂−N (1)), 54.2 (2CH₂−N (pyrrolidin)), 48.7 (CH−N), 36.8

(CH₂−CO), 34.1 (2CH₂), 32.1 (CH₂), 31.8 (CH₂), 29.8 (4CH₂), 29.7

(CH₂), 29.5 (CH₂), 29.4 (CH₂), 29.2 (CH₂), 26.3 (CH₂), 25.8 (CH₂),

23.6 (2CH₂−CH₂−N (pyrrolidin)), 22.8 (CH₂), 22.8 (CH₂), 14.3

(CH₃), 14.2 (CH₃). HRMS (ESI-TOF) m/z: [M + H]⁺calcd for

C₃₀H₆₁N₂O₃, 497.4682; found, 497.4671. Mp: 59−61 °C.

N-((2S,3S,4R)-3,4-Isopropylidenedioxy-1-(morpholino)-

octadecan-2-yl)octanamide (55e).

A solution of aziridine derivative 4 (74.7 mg, 0.16 mmol) in dry DMF

(3 mL), was treated with lithium perchlorate (137.0 mg, 1.28 mmol) for

30 min. Then, a 1.04 M solution of diethanolamine (461 μL, 0.48 mmol)

in DMF was added and the resulting mixture was heated to 80 °C and

stirred for 4 days. The reaction mixture was allowed to reach room

temperature, it was diluted with DCM (15 mL) and the organic layer

was washed with water (3 × 15 mL). Then, the organic layer was dried

over Na₂SO₄and ﬁltered, and the solvent was removed in vacuo to give a

crude, which was puriﬁed by ﬂash chromatography (silica gel, DCM/

MeOH 9.7:0.3 + 1% aq NH₃) to give pure product 55f as a pale yellow

oil (79.4 mg, 87%). [α]²⁰_D−2.4 (c 1.09, CHCl₃). IR (ﬁlm): ν = 3291,

2985, 2953, 2924, 2854, 1644, 1545, 1458, 1219, 1070 cm⁻¹. ¹H NMR

(500 MHz, CDCl₃) δ 6.46 (br s, 1H (NH)), 4.16−4.08 (m, 3H (2CH−

O and CH−N)), 3.67−3.57 (m, 4H (2CH₂−O)), 2.87 (br d, A part of

Adduct 55e was synthesized from 4 (52.7 mg, 0.11 mmol), lithium

perchlorate (96.3 mg, 0.91 mmol) and morpholine (30 μL, 0.34 mmol)

in dry MeCN (2 mL), according to General Procedure 3. In this case, the

reaction mixture was diluted with diethyl ether (2 mL) and the organic

layer was washed with water (3 × 2 mL). Then, the organic layer was

dried over MgSO₄and ﬁltered, and the volatiles were removed in vacuo

to give octanamide 55e as a colorless oil (54.7 mg, 87%). [α]²⁰_D−22.1

3022

dx.doi.org/10.1021/jo500061w | J. Org. Chem. 2014, 79, 2993−3029

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Aziridine ring opening for the synthesis of sphingolipid analogues: Inhibitors of sphingolipid-metabolizing enzymes

DOI: 10.1021/jo500061w

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