Synthesis and Evaluation of Hybrid Structures Composed of Two Glucosylceramide Synthase Inhibitors

DOI: 10.1002/cmdc.201500407

Full Papers

Synthesis and Evaluation of Hybrid Structures Composed

of Two Glucosylceramide Synthase Inhibitors

Richard J. B. H. N. van den Berg,^[a]Erwin R. van Rijssel,^[a]Maria Joao Ferraz,^[a]Judith Houben,^[a]

Anneke Strijland,^[b]Wilma E. Donker-Koopman,^[b]Tom Wennekes,^[a]Kimberly M. Bonger,^[a]

Amar B. T. Ghisaidoobe,^[a]Sascha Hoogendoorn,^[a]Gijsbert A. van der Marel,^[a]

Jeroen D. C. CodØe,^[a]Herman S. Overkleeft,*^[a]and Johannes M. F. G. Aerts*^{[a, b]}

Glucosylceramide metabolism and the enzymes involved have

attracted significant interest in medicinal chemistry, because

aberrations in the levels of glycolipids that are derived from

glucosylceramide are causative in a range of human diseases

including lysosomal storage disorders, type 2 diabetes, and

neurodegenerative diseases. Selective modulation of one of

the glycoprocessing enzymes involved in glucosylceramide

metabolism—glucosylceramide synthase (GCS), acid glucosyl-

ceramidase (GBA1), or neutral glucosylceramidase (GBA2)—is

therefore an attractive research objective. In this study we

took two established GCS inhibitors, one based on deoxynojiri-

mycin and the other a ceramide analogue, and merged charac-

teristic features to obtain hybrid compounds. The resulting 39-

compound library does not contain new GCS inhibitors; how-

ever, a potent (200 nm) GBA1 inhibitor was identified that has

little activity toward GBA2 and might therefore serve as a lead

for further biomedical development as a selective GBA1 modu-

lator.

Introduction

Glucosylceramide synthase (GCS) has emerged in recent years

as an attractive target for drug development both in relation

to lysosomal storage disorders (in particular Gaucher disease)

and type 2 diabetes.^[1]GCS catalyzes the transfer of glucose

from UDP-glucose to ceramide to form glucosylceramide

(Figure 1, left panel).^[2]In Gaucher disease, glucosylceramide

accumulates due to an inherited deficiency in acid glucosylcer-

amidase (GBA1).^[3]Two decades ago Platt, Butters, and col-

leagues discovered that the modified iminosugar, N-butyldeox-

ynojirimycin (miglustat, Zavesca, 1) is an inhibitor of GCS.^[4]In

2002 Zavesca entered clinical practice in what has become

known as substrate reduction therapy. Administration of Zaves-

ca to mildly affected type 1 Gaucher patients that carry N370S

GBA1 results in lowering glucosylceramide levels to such an

extent that accumulation of this glycolipid due to partially im-

paired GBA1 action is prevented.^[5]In 1998 we reported that

enlarging the hydrophobic N-alkyl group that is appended to

the deoxynojirimycin core, as in N-adamantanemethoxypentyl

deoxynojirimycin (AMP-DNM, 2) leads to a considerable in-

crease in GCS inhibitory potency.^[6]This finding has been con-

firmed in recent years in several studies, and a variety of imino-

sugar-based GCS inhibitors that differ in the nature of the

N substituent but also in configuration of the piperidine imino-

sugar have been described.^[7,8]Coinciding with these findings,

studies were reported indicating that altered glycolipid levels,

and in particular the ganglioside GM3 (aNeu5Ac(2-3)-b-d-

Galp(1-4)-b-d-Glcp(1-1)Cer), which is the result of a high-fat

diet, negatively influences insulin signaling by interfering with

the insulin receptor.^[9]

In 2007 we disclosed that AMP-DNM 2 decreases GM3 levels

by partial inhibition of GCS in animal models of type 2 diabe-

tes, and in this way restores insulin signaling.^[10a]We recently

extended this work by the generation of a focused library of

N-alkyldeoxynojirimycin derivatives, and we found that biphen-

yl-substituted iminosugars are more potent GCS inhibitors

than our aliphatic adamantyl derivatives.^[10b]Next to deoxyno-

jirimycin-type iminosugars, several other compound classes

have been identified as GCS inhibitors. Ceramide analogues 3

have gained considerable attention in recent years. Eliglustat

(3, R=C₇H₁₅) has been approved as an alternative to Zavesca

in substrate reduction therapy for patients of Gaucher dis-

ease^[11]and has also been shown to increase insulin signaling

in animal models of type 2 diabetes.^[12]Eliglustat is the result

of extensive medicinal chemistry studies over the past decades

based on a parent compound, 1-phenyl-2-decanoyl-3-morpho-

lino-1-propanol (PDMP) described by Vunman and Radin in

1980 as a GCS inhibitor.^[13]Finally, screening of large compound

collections in a GCS inhibition assay followed by medicinal

[a] Dr. R. J. B. H. N. van den Berg, Dr. E. R. van Rijssel, M. J. Ferraz, J. Houben,

Dr. T. Wennekes,⁺Dr. K. M. Bonger, Dr. A. B. T. Ghisaidoobe,

Dr. S. Hoogendoorn, Prof. Dr. G. A. van der Marel, Dr. J. D. C. CodØe,

Prof. Dr. H. S. Overkleeft, Prof. Dr. J. M. F. G. Aerts

Leiden Institute of Chemistry, Leiden University

Gorlaeus Laboratories, Einsteinweg 55, 2300 RA Leiden (The Netherlands)

E-mail: h.s.overkleeft@chem.leidenuniv.nl

j.m.aerts@amc.uva.nl

[b] A. Strijland, W. E. Donker-Koopman, Prof. Dr. J. M. F. G. Aerts

Department of Medical Biochemistry, Academic Medical Center

University of Amsterdam, Meibergdreef 9, 1105 AZ Amsterdam (The Nether-

lands)

[⁺] Present address:

Laboratory of Organic Chemistry, Wageningen University

Dreijenplein 8, 6703 HB Wageningen (The Netherlands)

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Figure 1. Glucosylceramide metabolism (left), established glucosylceramide synthase inhibitors 1–3 and hybrid structures 4 that are subject of the studies re-

ported herein.

chemistry optimization has led to the identification of

a number of functionalized amino acids (serine, tryptophan,

phenylalanine cores) that are currently being pursued as leads

for combating type 2 diabetes by GCS inhibition.^[14]

glycosyl hydrolases.^[7b,8,19]A second strategy we recently inves-

tigated and that proved unrewarding is testing a model^[20]pro-

posed by Platt and Butters, who reasoned that N-butyldeoxy-

nojirimycin acts on GCS not as a glucose mimic, but rather as

a ceramide mimic. In this model, which has not yet been sub-

stantiated due to a lack of structural data on GCS (the mem-

brane-associated enzyme has defied efforts to obtain crystallo-

graphic data), the hydroxy substituents at positions C2 and C3

and the hydroxymethyl group at C5 (glucopyranose number-

ing) of the piperidine core mimic the two hydroxy groups of

ceramide, with the N-alkyl chain as one of the ceramide alkyl

chains. According to this model the C2 OH group would be re-

dundant, and we thought to capitalize on this by testing N-al-

kylated derivatives of the natural product fagomine (2-deoxy-

deoxynojirimycin) in its eight configurational isomers. This li-

brary contained no effective GCS inhibitors.^[21]In the current

work we report on a related strategy to design potentially new

GCS inhibitors, which is based on potential structural similari-

ties in iminosugars 1 and 2, and ceramide analogue 3. The pyr-

rolidine ring in 3 has been substituted for piperidine and mor-

pholine in various studies, and all these varieties are accommo-

dated by GCS.^[22]We reasoned that 3 and its analogues might

act as bisubstrate analogues, with the pyrrolidine moiety occu-

pying the glucose binding side and the branched hydrophobic

group that of ceramide.^[22f]A similar model may apply to deox-

ynojirimycin derivatives 1 and 2, with the iminosugar core

binding at a putative glucose-binding site and the hydropho-

bic group in the corresponding ceramide-binding site.^[23]We

decided to investigate this model by designing a concise li-

brary of hybrid structures that are composed of the core

amino alcohol structure in 3, feature a polyhydroxylated pyrro-

lidine or piperidine iminosugar, and differ with respect to the

N-acyl chain. Herein we report on the development and inhibi-

tory activity against GCS, GBA1, and GBA2 of a 39-compound

library designed according to these guidelines.

In the search for new GCS inhibitors, selectivity with respect

to other glycoprocessing enzymes is an important issue. In par-

ticular, glycosidases that hydrolyze glucosylceramide are po-

tential off-targets. Next to GBA1, we and others have discov-

ered

a second non-lysosomal neutral glucosylceramidase

termed GBA2 (Figure 1, left panel).^[15]Ideally these enzymes are

untouched, and we routinely screen potential GCS inhibitors

also against GBA1 and GBA2. These glycosidases also have

therapeutic potential in their own right. GBA1 inhibitors are ex-

tensively pursued in what has become known as chemical

chaperone therapy: a conceptually new therapeutic strategy

that has yet to be validated in the clinic and that aims at re-

storing active lysosomal GBA1 levels through stabilizing the

fold of the nascent protein in the endoplasmic reticulum.^[16]

Mutations in GBA1 have also been implicated as risk factors for

Parkinsonism,^[17]whereas excessive degradation of glucosylcer-

amide by GBA2 is thought to play a role in neuropathology.^[18]

When looking at the different compound classes currently pur-

sued as GCS inhibitors, it is perhaps obvious that the ceramide

analogues are GCS selective, at least with respect to GBA1 and

GBA2 (next to 3, these include the aforementioned amino acid

derived leads; after all, ceramide itself is the result of a conden-

sation between serine and palmitate, and it should thus come

as no surprise that serine derivatives featuring hydrophobic

substituents target GCS). The same cannot be said of the deox-

ynojirimycin derivatives 1 and 2, both of which give considera-

ble inhibition of GBA1, GBA2 and a range of other (including

intestinal) glycosidases as well.^[7b]In fact, deoxynojirimycin and

its derivatives are renowned for their glycosidase inhibitory ac-

tivity, and the finding by Platt and Butters that such com-

pounds also target GCS came as a major surprise, considering

that glycosyltransferases are generally not affected by iminosu-

gars. One strategy to achieve GCS selectivity with respect to

GBA1 and GBA2 is to alter the configuration of the iminosugar

core. Indeed, GCS is effectively inhibited by both d-galacto-

and l-ido-configured N-alkylated iminosugars, with the latter

especially being much less potent at inhibition of a range of

Results and Discussion

The synthetic strategy by which we assembled our 39-com-

pound library of hybrid iminosugar–ceramide analogues is de-

picted in Scheme 1. In the first step, fully protected aminodiol

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Scheme 1. Reagents and conditions: a) AcOH, THF/H₂O, then MsCl, pyridine, À208C; b) DMF, K₂CO₃, 808C, 72 h; c) LiOH, dioxane/H₂O, microwave, 30 min;

d) DMF, RT.

5,^[24]which featured as an advanced intermediate in the syn-

thesis of 3, was desilylated followed by introduction of the pri-

mary mesylate to give compound 6 in 98% overall yield. The

mesylate in 6 was substituted for deoxynojirimycin 7 (6!8,

84%), after which the carbamate protecting group was re-

moved under basic conditions (8!9, 91%). In the final step

the secondary amine in 9 was acylated with the succinic ester

of 5-adamantanemethyloxypentanoic acid 10 to give hybrid

structure 11 in 77% yield.

By following this synthetic scheme, but with variation in the

nature of the iminosugar (deoxynojirimycin 7 in Scheme 1)^[25]

that is reacted with the mesylate in 6, the succinyl ester (ada-

mantane spacer 10 in Scheme 1) that is condensed with the

secondary amine in 9, or both, we prepared a 39-compound li-

brary.

The library (Figure 2) was assembled from four polyhydroxyl-

ated piperidines, six polyhydroxylated pyrrolidines, as well as

the bare pyrrolidine, piperidine, and morpholine substituents

that have proven affinity for GCS (see the Experimental Section

below for conditions, yields, and analytical data). Each of these

13 cyclic secondary amines was connected to the core amino-

diol that is the common feature in all compounds, and further

variation was provided by introducing three different N-acyl

groups: next to the adamantane spacer (taken from lead 2),

the nonanoic acid moiety as present in lead 3, and O-(p-me-

thoxypenyl)hydroxyacetate as another hydrophobic moiety

found in GCS inhibitors of the PDMP series.^[12]In all, this led to

the following 13 series of three compounds each: polyhydrox-

ylated piperidines featuring the d-gluco configuration (11–13),

the l-ido configuration (14–16), the d-galacto configuration

(17–19) and the l-altro configuration (20–22); polyhydroxylat-

ed pyrrolidines featuring the d-lyxo configuration (23–25), the

d-arabino configuration (26–28), the d-xylo configuration (29–

31), the d-ribo configuration (32–34), the l-arabino configura-

tion (35–37) and the l-lyxo configuration (38–40); along with

the analogous compounds featuring an unsubstituted piperi-

dine (41–43), morpholine (44–46), and pyrrolidine (3, 47, 48).

The library of compounds were next assessed for their inhib-

itory potential against GCS, GBA1, and GBA2 in comparison

with lead structures 2 and 3, which were at the basis of the

design of the hybrid structures. For GCS we used a previously

Figure 2. Structures of the 39-member compound library.

reported^[6]in situ assay that relies on a fluorescent ceramide

analogue as a readout. We selected 10 mm as a cutoff concen-

tration, above which execution of this cell-based assay is cum-

bersome, and furthermore because GCS inhibitors with an IC₅₀

value at or above 10 mm arguably have no therapeutic poten-

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tial. GBA1 and GBA2 inhibition was measured in in vitro as-

says,^[7b]and for this, we opted for 1 mm as cutoff. In this initial

screen aimed to weed out inactive compounds, IC₅₀values

were determined based on a single experiment. As can be im-

mediately observed from Table 1, none of the polyhydroxylat-

ed pyrrolidines (compounds 23–40) or piperidines (compounds

11–22) inhibit GCS at concentrations up to 10 mm. We there-

fore conclude that our design to arrive at bisubstrate analogue

type GCS inhibitors is at fault. Apparently (and one must be

careful to draw conclusions on binding modes without struc-

tural data), the pyrrolidine (3, 47, 48), piperidine (41–43), and

morpholine (44–46) series that inhibit GCS in the nanomolar

to low micromolar range (as expected from published data)

act through a mode that does not recruit a putative glucose

binding site. Clearly, appending multiple hydroxy functions to

the pyrrolidine/piperidine pharmacophore has a detrimental

effect irrespective of the stereochemical information thus intro-

duced (the wide range of configurational isomers we used at

least allows this conclusion). These observations do not pre-

clude the presence of a glucopyranose binding site in the GCS

catalytic pocket, and that is the target of the deoxynojirimycin-

type GCS inhibitors 2 and 3. Perhaps introducing a spacer be-

tween the two pharmacophores would result in more effective

GCS inhibitors. On the positive side, our compound library con-

tains a number of rather potent GBA1 inhibitors in the pyrroli-

dine series. Of these, especially the d-arabino-configured deriv-

atives are of interest, as they display good selectivity for GBA1

over GBA2. To further probe these results, we obtained IC₅₀

values derived from triplicate measurements for d-arabino pyr-

rolidine derivatives 26–28 against GBA and GBA2, in a compari-

son with the l-ido-configured piperidine series 14–16 (about

equally active toward GBA1 in our initial assessment, while at

the same time less selective because of moderately good

GBA2 activity) and AMP-DNM 2 as a positive control. These ex-

periments (values listed in Table 2) confirm our initial findings.

Thus, d-arabino-pyrrolidine 26 inhibits GBA1 with an IC₅₀

value of 1.8 mm, in the range of what we observed for AMP-

Table 2. GBA1 and GBA2 inhibition assay results for compounds 2, 14,

15, 16, 26, 27, and 28.

Compd

IC₅₀[mm]

GBA1

GBA2

2

1.0Æ0.1

2.4Æ0.1

6.9Æ1.2

12.9Æ0.5

1.8Æ0.2

1.6Æ0.1

15.2Æ0.5

0.000Æ0.00019

0.005Æ0.0003

0.1Æ0.03

14

15

16

26

27

28

1.6Æ0.3

67.2Æ1.6

41.5Æ6.1

118.8Æ15.4

[a] Apparent IC₅₀values are the meanÆSD from triplicate measurements.

DNM 2 (1.0 mm). In contrast, whereas 2 is a very potent (IC₅₀:

1 nm) GBA2 inhibitor, 26 is a relatively poor GBA2 inhibitor

(IC₅₀: 67 mm). In comparison, pyrrolidines 26–28 are relatively

poor GBA2 inhibitors, and this is in contrast to the l-ido-piperi-

dine series 14–16 that we included in the triplicate measure-

ments and that inhibit GBA1 in the same range, as evident

from Table 2. Indeed we have experienced in the past that N-

alkylated deoxynojirimycin derivatives and their configurational

isomers that inhibit GBA1 without exception are more potent

inhibitors of GBA2. Based on the results presented herein we

believe it may be worthwhile to pursue polyhydroxylated N-al-

kylated pyrrolidines as potent and selective GBA1 inhibitors.

In conclusion, we have developed a straightforward synthet-

ic route to obtain hybrid structures that encompass pharmaco-

phores stemming from two distinct classes of glucosylcera-

mide synthase (GCS) inhibitors. The fact that neither of these

compounds are potent GCS inhibitors is of itself of interest, as

it provides more, albeit circumstantial, information on how the

separate compounds (2 and 3) may bind to the GCS active

site. Our compound collection also adds to the growing list of

functionalized iminosugar derivatives, and screening against

a wider array of glycoprocessing enzymes may yield potentially

Table 1. GCS, GBA1, and GBA2 inhibition assay results.^[a]

Compd

IC₅₀[mm]

Compd

IC₅₀[mm]

Compd

IC₅₀[mm]

GCS

0.2

0.1

>10

GBA1

GBA2

0.001

>1000

0.03

GCS

GBA1

GBA2

GCS

>10

1.5

GBA1

GBA2

2

3

0.2

70

0.2

0.3

1.7

1.5

2.0

4.5

2.0

24

25

26

27

28

29

30

31

32

33

34

35

36

37

38

>10

25

750

2.0

0.2

12.5

5.0

30

100

40

50

200

8.0

10

175

30

350

>1000

90

60

200

>1000

200

>1000

50

39

40

41

42

43

44

45

46

47

48

150

175

120

500

>1000

750

>1000

150

>1000

500

>1000

11

12

13

14

15

16

17

18

19

20

21

22

23

>10

0.2

2.2

0.03

0.1

1.0

3.5

50

6.0

50

1.0

0.8

0.75

0.8

100

>1000

30

500

45

>1000

0.1

0.05

15

150

37.5

100

>1000

20

>1000

500

>1000

150

[a] Apparent IC₅₀values from single determinations.

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acid) on a mass spectrometer (Thermo Finnigan LTQ Orbitrap)

equipped with an electrospray ion source in positive mode (source

voltage: 3.5 kV, sheath gas flow: 10 mLmin^À1, capillary tempera-

ture: 2508C) with resolution R=60000 at m/z 400 (mass range

m/z: 150–2000) and dioctylphthalate (m/z=391.28428) as a lock

mass. The high-resolution mass spectrometer was calibrated prior

to measurements with a calibration mixture (Thermo Finnigan). De-

oxynojirimycin 7^[25a]and its congeners l-ido-deoxynojirimycin,^[7b]d-

galacto-deoxynojirimycin,^[28,15b]and l-altro-deoxynojirimycin^[29]

were prepared as reported previously by us. 2,3,5-Tri-O-benzyl-d-

lyxono-1,4-lactone, 2,3,5-tri-O-benzyl-l-xylofuranose, 2,3,5-tri-O-

benzyl-l-arabinofuranose, 2,3,5-tri-O-benzyl-d-ribofuranose, and

2,3,5-tri-O-benzyl-d-xylofuranose were synthesized as described.^[30]

4-Methoxyphenyl-2-cyanoethyl ether was synthesized from 4-me-

thoxyphenol as published by DeWald et al.^[31]

new leads for development toward selective inhibitors, in anal-

ogy with the identified pyrrolidine 26, which selectively inhib-

its GBA1.

Experimental Section

Enzyme inhibition assays. The inhibitory potencies (IC₅₀values) of

the final compounds for GCS, GBA1, and GBA2 were determined

by exposing cells or enzyme preparations to an appropriate range

of iminosugar concentrations. IC₅₀values for GCS activity were

measured using living cells with NBD-ceramide as substrate.^[26]

Briefly, cells were incubated in 1 mL of medium with 50 nmol C6-

NBD-ceramide (6-[N-methyl-N-(7-nitrobenz-2-oxa-1,3-diazol-4-yl)a-

minododecanoyl]sphingosine) in the presence of increasing com-

pound concentrations. The cells were harvested after 2 h followed

by lipid extraction and separation by thin-layer chromatography

(TLC). Formed C6-NBD-glucosylceramide was quantified using a Mo-

lecular Dynamics Typhoon phosphorimaging device. IC₅₀values

were determined from the titration curves. The experiment was re-

peated three times. IC₅₀values for lysosomal GBA1 were measured

using 4-methylumbelliferyl-b-d-glucoside as substrate.^[27]Briefly, re-

combinant GBA1 was incubated with increasing compound con-

centrations. Enzyme activity was determined with 3.7 mm 4-meth-

ylumbelliferyl-b-d-glucopyranoside (4-MU-b-glucoside) in McIlvaine

buffer (0.1m citrate and 0.2m phosphate buffer), pH 5.2, 0.1%

Triton X-100 (v/v) and 0.2% (w/v) sodium taurocholate. Assays per-

formed in triplicate were incubated at 378C and quenched by the

addition of glycine/NaOH (pH 10.6). The amount of liberated 4-MU

was determined with a PerkinElmer Life Sciences LS30 fluorimeter.

IC₅₀values for the non-lysosomal glucocerebrosidase (GBA2) were

measured with the same substrate as described earlier.^[28,15b]Briefly,

GBA2-rich membrane suspensions were prepared from enzyme-

overexpressing HEK cells and incubated with 3.7 mm 4-MU-b-glu-

coside in McIlvaine buffer (0.1m citrate and 0.2m phosphate

buffer), pH 5.8, with or without pre-incubation for 30 min at 48C

with 1 mm conduritol-B-epoxide (CBE, Sigma) to inhibit the lysoso-

mal glucocerebrosidase, GBA1. Assays were incubated at 378C and

quenched by the addition of glycine/NaOH (pH 10.6). The amount

of liberated 4-MU was determined with a PerkinElmer Life Sciences

LS30 fluorimeter. Assays were performed in triplicate.

General procedure for condensing N-hydroxysuccinimide with

50, 51 and 54. To a solution of the free acid in CH₂Cl₂(1 mmol/

5 mL) were added N-hydroxysuccinimide (1.1 mol) and N-(3-dime-

thylaminopropyl)-N’-ethylcarbodiimide hydrochloride (1.2 mmol).

The mixture was stirred for 6 h, after which TLC analysis showed

complete consumption of the starting material. The organic layer

was washed with aqueous saturated NH₄Cl (50 mL), dried over

Na₂SO₄, filtered and concentrated. The residue was purified by

silica gel column chromatography with EtOAc and petroleum ether

(PE) as eluent (20:1!5:4, v/v) (Scheme 2).

5-(Adamantane-1-yl-methoxy)pentanoic acid (50): To a mixture of

5-(adamantan-1-yl-methoxy)-1-pentanal^[24a](49, 5.12 g, 20.5 mmol)

in CH₂Cl₂/tBuOH/H₂O (100 mL, 6:3:1, v/v/v) was added TEMPO

(0.624 g, 4.0 mmol) and BAIB (9.65 g, 30.0 mmol). After 24 h, a mix-

ture of aqueous saturated Na₂S₂O₃and aqueous saturated NaHCO₃

(30 mL, 2:1, v/v) was added, and the reaction mixture was stirred

vigorously. Subsequently, the volatiles were removed and the

aqueous layer extracted with EtOAc (3100 mL). The combined or-

ganic layers were dried (Na₂SO₄), filtered and concentrated. The

residue was purified by silica gel column chromatography with

EtOAc and PE as solvent system (1:19!3:1, v/v) affording 50 as

colorless oil (4.00 g, 15.0 mmol, 73%); R_f=0.45 (EtOAc/PE 1:4, v/v);

¹H NMR (400 MHz, CDCl₃): d=1.52 (brs, 6H, H₂adamantane), 1.52–

1.75 (m, 10H, H₂adamantane, H₂-3 pentanoic acid, H₂-4 pentanoic

acid), 1.95 (brs, 3H, CH adamantane), 2.39 (dd, J=7.2, 7.6 Hz, 2H,

H₂-2 pentanoic acid), 2.95 (s, 2H, H₂adamantane), 3.40 (t, J=

6.0 Hz, H₂-2 pentanoic acid), 11.05 ppm, (brs, 1H, OH pentanoic

acid); ¹³C NMR (100 MHz, CDCl₃): d=21.5 (CH₂pentanoic acid), 28.2

(CH adamantane), 28.8, 33.8 (CH₂pentanoic acid), 34.0 (Cq ada-

mantane), 37.2, 39.7 (CH₂adamantane), 71.0 (CH₂pentanoic acid),

81.9 (CH₂methoxy), 179.9 ppm, (C=O pentanoic acid).

Synthesis: general information. Reactions were monitored by TLC

analysis using silica gel coated plates (0.2 mm) with detection by

spraying with a solution of KMnO₄(5 gL^À1) and K₂CO₃(25 gL^À1) fol-

lowed by charring. Column chromatography was performed on

silica gel (40–63 mm). Microwave reactions were performed in a Bi-

otage Initiator 2.5 microwave reactor. Wattage was automatically

adjusted to maintain the desired temperature. Yields were not op-

timized. ¹H and ¹³C NMR spectra were recorded on 500–125 MHz

or 400–100 MHz spectrometers. Chemical shifts (d) are given in

ppm relative to tetramethylsilane as internal standard. Coupling

constants (J) are given in Hz. All ¹³C NMR spectra are proton decou-

pled. For LC–MS analysis, an HPLC system (detection simultaneous-

ly at l 213, 254 nm and evaporative light detection) equipped with

an analytical C₁₈column (4.6 mm (1) 250 mm (l), 5 mm particle

size) in combination with buffers A: H₂O, B: MeCN, C: 1.0% aque-

ous trifluoroacetic acid (TFA), coupled with an electrospray inter-

face (ESI) was used. For RP-HPLC purifications (detection simultane-

ously at l 213, 254 nm), an automated HPLC system equipped with

a semi-preparative C₁₈column (5 mm C₁₈, 10 , 15021.2 mm) was

used. The applied buffers were A: H₂O+TFA (1%) and B: MeCN.

High-resolution mass spectra were recorded by direct injection

(2 mL of a 2 mm solution in H₂O/MeCN 50:50 v/v and 0.1% formic

5-(Adamantane-1-yl-methoxy)pentanoic acid succinimide ester

(10): Synthesized according to the general procedure for condens-

ing N-hydroxysuccinimide starting from 50. Yield 3.20 g (8.8 mmol,

1

88%); R_f=0.30 (EtOAc/PE 1:3, v/v); H NMR (400 MHz, CDCl₃): d=

1.52 (brs, 6H, H₂adamantane), 1.63–1.72 (m, 8H, H₂adamantane,

H₂-4 pentanoic acid), 1.82 (dt, J=7.2, 7.6 Hz, 2H, H₂-3 pentanoic

acid), 1.95 (brs, 3H, CH adamantane), 2.66 (dd, J=7.2, 7.6 Hz, 2H,

H₂-2 pentanoic acid), 2.83 (brs, 4H, 2H₂succinimide), 2.95 (s, 2H,

H₂adamantane), 3.41 ppm, (t, J=6.0 Hz, H₂-2 pentanoic acid);

¹³C NMR (100 MHz, CDCl₃): d=21.6 (CH₂pentanoic acid), 25.5 (CH₂

succinimide), 28.2 (CH adamantane), 28.5, 30.6 (CH₂pentanoic

acid), 34.0 (Cq adamantane), 37.2, 40.0 (CH₂adamantane), 70.6

(CH₂pentanoic acid), 81.9 (CH₂methoxy), 168.6 (C=O pentanoic

acid), 169.1 ppm, (C=O succinimide); IR (thin film): n˜ =2895, 1700,

1265, 1245, 1116, 1093 cm^À1

.

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Mesylate 6. Compound 5 (6.00 g,

12.3 mmol) was dissolved in a mix-

ture of AcOH, THF and H₂O

(100 mL, 3/1/1, v/v/v) and subse-

quently stirred for 48 h. The vola-

tiles were evaporated and the resi-

due purified by silica gel column

chromatography with EtOAc and

PE as eluent (1:1!1:0, v/v) yielding

the free primary hydroxy com-

pound as a white solid (2.87 g,

11.4 mmol

93%);

¹H NMR

(600 MHz, CDCl₃): d=3.59 (d, 1H,

J=10.2 Hz, 1H, Ha hydroxymethyl),

3.75 (d, J=11.4 Hz, 1H, Hb hydrox-

ymethyl), 3.79 (m, 1H, H-4 oxazoli-

dine), 4.20 (s, 4H, 2H₂ethylene),

4.50 (s, 1H, OH), 5.20 (d, J=6.0 Hz,

1H, H-5 oxazolidine), 6.77–6.87 (m,

3H, Harm), 7.27 ppm, (s, 1H, NH);

¹³C NMR (200 MHz, CDCl₃): d=61.8

(C-4 oxazolidine), 62.8 (CH₂hydrox-

ymethyl), 64.1, 64.2 (CH₂ethylene),

79.6 (C-4 oxazolidine), 115.1, 117.6,

119.1 (CHarm), 131.4, 143.6, 144.0

Scheme 2. Reagents and conditions: a) TEMPO, BAIB, CH₂Cl₂/tBuOH/H₂O (6:3:1 v/v/v); b) EDC·HCl, N-hydroxysuccini-

mide; c) HCl, EtOH; d) AcOH, THF/H₂O, then MsCl, pyridine.

Nonanoic acid N-hydroxysuccinimide ester (52): Synthesized ac-

(Cq Carm), 160.1 ppm, (C=O); IR (thin film): n˜ =1733, 1511, 1350,

1287, 1164, 1124, 1065 cm^À1; LC–MS: t_R=4.83 min (linear gradient

10!90% B); ESI-MS: m/z=252.0 [M+H]⁺, 503.1 [2M+H]⁺. To

a cooled (À208C) solution of the desilylated compound (2.864 g,

11.4 mmol) in pyridine (110 mL) was added methanesulfonyl chlo-

ride (28.5 mmol, 3.26 g, 2.2 mL). After 2 h the reaction was

quenched by the addition of EtOH (2 mL) and the volatiles evapo-

rated. The residue was dissolved in EtOAc (100 mL), and the organ-

ic layer washed with aqueous HCl (1m, 420 mL), aqueous saturat-

ed NaHCO₃(220 mL), brine (20 mL) and subsequently dried

(Na₂SO₄) and filtered. The volatiles were evaporated and the resi-

due purified by silica gel column chromatography with EtOAc and

PE as eluent (1:1!1:0, v/v) yielding the title compound as colorless

oil (2.86 g, 11.4 mmol 76%); R_f=0.50 (neat EtOAc); ¹H NMR

(400 MHz, CDCl₃): d=3.11 (s, 3H, H₃Ms), 4.01 (dt, J=4.4, 5.5 Hz,

1H, H-5 oxazolidine), 4.26 (dd, 1H, J=5.4, 10.4 Hz, 1H, Ha methyl

methanesulfonate), 4.27 (s, 4H, 2H₂ethylene), 4.34 (dd, J=4.4,

10.7 Hz, 1H, Hb methyl methanesulfonate), 5.21 (d, J=5.7 Hz, 1H,

H-4 oxazolidine), 6.83–6.91 (m, 3H, Harm, NH), 7.33 ppm (s, 1H

Harm); ¹³C NMR (100 MHz, CDCl₃): d=37.5 (CH₃Ms), 59.0 (C-5 oxa-

zolidine), 64.2, 64.3 (CH₂ethylene), 68.2 (CH₂methyl methanesulfo-

nate), 78.9 (C-4 oxazolidine), 114.8, 117.8, 118.8 (CHarm), 130.4,

143.8 ppm (Cq Carm); IR (thin film): n˜ =1733, 1511, 1350, 1287,

1164, 1124, 1065 cm^À1; LC–MS: t_R=4.63 min (linear gradient 10!

90% B); ESI-MS: m/z=330.1 [M+H]⁺, 346.9 [M+NH₄]⁺, 659.1

[2M+H]⁺, 676.1 [2M+NH₄]⁺.

cording to the general procedure for condensing N-hydroxysuccini-

mide starting from 51. Yield 3.10 g (12.2 mmol, 96%); R_f=0.45

(EtOAc/PE 1:3, v/v); H NMR (400 MHz, CDCl₃): d=0.88 (t, J=6.8 Hz,

1

3H, CH₃), 1.28–1.44 (m, 10H, 5H₂nonanoic acid), 1.74 (dt, J=7.2,

7.6 Hz, 2H, H₂-3 nonanoic acid), 2.60 (t, J=7.6 Hz, 2H, H₂-2 nona-

noic acid), 2.83 ppm, (brs, 4H, 2H₂succinimide); ¹³C NMR

(100 MHz, CDCl₃): d=14.0 (CH₃), 22.6, 24.5 (CH₂nonanoic acid),

25.6 (CH₂succinimide), 28.8, 29.0, 30.9, 31.7 (CH₂nonanoic acid),

168.8 (C=O nonanoic acid), 169.1 ppm, (C=O succinimide); IR (thin

film): n˜ =2921, 1815, 1784, 1720, 1208, 1069 cm^À1

.

3-(4-Methoxyphenoxy)propanoic acid (54): 4-Methoxyphenyl-2-

cyanoethyl ether (53, 15.0 g, 84.6 mmol) was dissolved in concen-

trated HCl (37%, 32 mL) and held at reflux for 8 h. The mixture was

filtered and the filter cake rinsed with H₂O. The solids were dis-

solved in aqueous NaOH (1m, 100 mL) and the mixture was fil-

tered. The filtrate was acidified and the formed crystals were isolat-

ed by filtration, rinsed with H₂O and dried under reduced pressure.

Yield 13.86 g (70.6 mmol, 83%); R_f=0.40 (EtOAc/PE 1:1, v/v);

¹H NMR (400 MHz, CDCl₃): d=2.82 (t, J=6.4 Hz, 2H, H₂propanoic

acid), 3.76 (s, 3H, OMe), 4.20 (t, J=6.4 Hz, 2H, H₂propanoic acid),

6.81–6.87 ppm, (m, 4H, Harm phenoxy); ¹³C NMR (100 MHz, CDCl₃):

d=34.5 (CH₂propanoic acid), 55.7 (OMe), 63.9 (CH₂propanoic

acid), 114.7, 118.8 (CHarm phenoxy), 152.5, 154.2 (Cq phenoxy),

177.1 ppm, (C=O propanoic acid); IR (thin film): n˜ =2932, 1687,

1506, 1222, 1047 cm^À1

.

3-(4-Methoxyphenoxy)propanoic acid N-hydroxysuccinimide

ester (55): Synthesized according to the general procedure for con-

densing N-hydroxysuccinimide starting from 54. Yield 2.93 g

General procedure for reaction pyrrolidines, piperidines and

morpholine with mesylate 6. Two stock solutions were prepared:

stock solution A containing a pyrrolidine, a piperidine or morpho-

line in N,N-dimethylformamide (DMF, 0.4 mm), stock solution B

with mesylate 6 in DMF (0.4 mm); 1 mL of stock solution A was

added to 1 mL of stock solution B and successively 3 equivalents

of K₂CO₃were added. The mixture was stirred at 808C for 72 h. The

mixture was filtered and the volatiles evaporated and the residue

purified by silica gel column chromatography with MeOH, EtOAc

and NH₄OH as solvent system (0:99:1!50:49:1, v/v/v) (Scheme 3).

1

(55.0 mmol, 98%); R_f=0.50 (EtOAc/PE 1:1, v/v); H NMR (400 MHz,

CDCl₃): d=2.84 (brs, 4H, 2H₂succinimide), 3.08 (t, J=6.4 Hz, 2H,

H₂propanoic acid), 3.77 (s, 3H, OMe), 4.28 (t, J=6.4 Hz, 2H, H₂

propanoic acid), 6.89–6.82 ppm, (m, 4H, Harm phenoxy); ¹³C NMR

(100 MHz, CDCl₃): d=25.6 (CH₂succinimide), 31.7 (CH₂propanoic

acid), 55.7 (OMe), 63.4 (CH₂propanoic acid), 114.7, 116.1 (CHarm

phenoxy), 166.0 (C=O propanoic acid), 168.8 ppm, (C=O succini-

mide); IR (thin film): n˜ =1816, 1778, 1736, 1506, 1207, 1075 cm^À1

.

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General procedure for oxazolidine saponification. The oxazoli-

dine derivative (1 mmol/35 mL solvent system) was dissolved in

a mixture of dioxane and H₂O (3:2, v/v) in a microwave tube. Sub-

sequently, 13 equivalents of LiOH were added and the microwave

tube sealed and heated for 30 min at 1658C. The mixture was neu-

tralized by the addition of aqueous HCl (1m). The solvents were

evaporated and the residue purified, for compounds 9, 58, 64, 76,

100, 102 and 104 by silica gel column chromatography with

MeOH, EtOAc and NH₄OH as solvent system (0:99:1!50:49:1, v/v/

v). Compounds 61, 70, 82, 88, 94 and 98 were used as crudes in

the next step, after HPLC analysis showed complete consumption

of the starting oxazolidine derivative, without the column chroma-

tography purification step.

145.2, 145.4 (Cq Carm), 161.6 ppm (C=O); IR (thin film): n˜ =3332,

2920, 1734, 1647, 1593, 1508, 1437, 1288, 1067, 1010, 922 cm^À1

;

LC–MS: t_R=5.44 min (linear gradient 0!50% B); ESI-MS: m/z=

397.0 [M+H]⁺, 793.3 [2M+H]⁺; HRMS [QTOF, MH⁺] m/z calculated

for C₁₈H₂₅N₂O₈397.16054, found 397.16048.

Compound 9: The oxazolidine in compound 8 was hydrolyzed ac-

cording to the saponification procedure described above. Yield

0.069 g (186 mmol, 91%); R_f=0.40 (EtOH/Et₂O/NH₄OH 6:3:1, v/v/v).

½a²⁰=15.18 (c=0.33 in MeOH); ¹H NMR (400 MHz, D₂O): d=2.34

D

(ddd, J=3.0, 4.5, 9.8 Hz, 1H, H-5), 2.43 (dd, J=10.8, 11.8 Hz, 1H, H-

1a), 2.63 (dd, J=10.3, 15.0 Hz, 1H, H-1’a), 2.74 (dd, J=4.7, 14.9 Hz,

1H, H-1’b), 2.95 (dd, J=4.9, 11.9 Hz, 1H, H-1b), 3.26 (t, J=9.1 Hz,

1H, H-3), 3.35 (t, J=9.4 Hz, 1H, H-4), 3.56 (ddd, J=4.9, 9.2, 10.6 Hz,

1H, H-2), 3.60 (ddd, J=4.7, 8.0, 10.4 Hz, 1H, H-2’), 3.69 (dd, J=2.8,

12.5 Hz, H-6a), 3.81 (dd, J=4.5, 12.6 Hz, H-6b), 4.34 (brs, 4H, 2H₂

ethylene), 4.65 (d, J=7.9 Hz, 1H, H-3’), 6.91–7.07 ppm (m, 3H,

Harm); ¹³C NMR (100 MHz, D₂O): d=50.7 (C-1’), 56.0 (C-2’), 57.7 (C-

1), 58.0 (C-6), 64.6 (2CH₂O), 66.3 (C-5), 68.4 (C-2), 69.8 (C-4), 71.6

(C-3’), 78.2 (C-3), 115.5, 117.8, 120.0 (CHarm), 132.7, 143.4,

142.5 ppm (Cq Carm); IR (thin film): n˜ =3329, 2924, 1508, 1286,

1067, 1041 cm^À1; LC–MS: t_R=4.08 min (linear gradient 0!50% B);

ESI-MS: m/z=370.9 [M+H]⁺, 741.4 [2M+H]⁺; HRMS [QTOF, MH⁺]

m/z calculated for C₁₇H₂₇N₂O₇371.18128, found 371.18130.

General procedure for condensing hydroxysuccinimide esters

10, 42 and 55 with secondary amines. Three stock solutions were

prepared: stock solution A containing amino alcohol in DMF

(1 mmol/40 mL DMF), stock solution B with hydroxysuccinimide

ester (1 mmol/70 mL DMF) and stock solution C consisting of DiPEA

in DMF (1 mmol/2 mL DMF). To stock solution A were added 1.1

equivalents of stock solution B followed by addition of 1.75 equiv-

alents of stock solution of C. The mixture was stirred for 18 h. The

volatiles were evaporated and the residue purified by RP-HPLC.

Compound 8: Compound 7 was reacted with mesylate 6 accord-

ing to the general procedure described above. Yield 0.081 g

(0.204 mmol, 84%); R_f=0.50 (MeOH/EtOAc/NH₄OH 40:60:5, v/v/v).

Compound 11: Compound 9 was reacted with 10 according to the

general condensation protocol described above. Yield 0.020 g

1

½a²⁰=25.2 (c=0.81 MeOH); ¹H NMR (400 MHz, MeOD): d=2.07

(32 mmol, 77%). ½a²⁰=11.0 (c=0.40 in MeOH); H NMR (400 MHz,

D

(dd, J=10.4, 11.4 Hz, 1H, H-1a), 2.12 (ddd, J=2.5, 3.5, 9.6 Hz, 1H,

H-5), 2.51 (dd, J=5.3, 13.0 Hz, 1H, H-1’a), 2.85 (dd, J=4.8, 11.3 Hz,

1H, H-1b), 3.13 (t, J=8.9 Hz, 1H, H-3), 3.16 (dd, J=8.8, 13.2 Hz, 1H,

H-1’b), 3.22–3.28 (m, 1H, H-2), 3.33 (t, J=8.8 Hz, 1H, H-4), 3.84–

3.89 (m, 2H, H-2’, H-6a), 3.93 (dd, J=2.6, 12.1 Hz, 1H, H-6b), 4.22

(s, 4H, 2H₂ethylene), 5.40 (d, J=5.3 Hz, 1H, H-3’), 6.82–6.88 ppm

(m, 3H, Harm); ¹³C NMR (100 MHz, MeOD): d=57.3 (C-1’), 58.6 (C-

1), 59.8 (C-6), 59.9 (C-2’), 65.6 (2CH₂O), 68.8 (C-5), 70.4 (C-2), 72.0

(C-4), 80.5 (C-3), 83.3 (C-3’), 116.0, 118.5, 120.0 (CHarm), 134.1,

D₂O): d=1.16–1.35 (m, 4H, H₂-3’’, H₂-4’’), 1.54 (brs, 6H, H₂adaman-

tane), 1.66–1.75 (m, 6H, H₂adamantane), 1.97 (brs, 3H CH adaman-

tane), 2.15 (brs, 2H, H₂-2’’), 2.79 (s, 2H, H₂adamantane), 3.01 (dd,

J=10.4, 14.4 Hz, 1H, H-1a), 3.13 (brs, 1H, H-5), 3.31 (t, J=6.0 Hz,

H₂-2’’), 3.40 (brs, 1H, H-1’a), 3.49 (t, J=9.2 Hz, 1H, H-3), 3.58 (brd,

J=8.2 Hz, 1H, H-1b), 3.69 (t, J=9.7 Hz, 1H, H-4), 3.77–3.84 (m, 2H,

H-1’b, H-2), 4.06 (q, J=12.4 Hz, H₂-6), 4.18 (brs, 4H, 2H₂ethyl-

ene), 4.51 (brs, 1H, H-2’), 4.96 (brs, 1H, H-3’), 6.80–6.92 ppm (m,

3H, Harm); ¹³C NMR (150 MHz, D₂O): d=22.0 (C-3’’), 28.3 (CH ada-

Scheme 3. Reagents and conditions: a) 6, K₂CO₃, DMF, 808C; b) LiOH, dioxane/H₂O, microwave, 1658C; c) 10, 52 or 55, DiPEA, DMF.

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mantane), 28.4 (C-4’’), 33.8 (Cq adamantane), 35.3 (C-2’’), 37.1 (CH₂

adamantane), 39.4 (CH₂adamantane), 50.7 (C-2’), 53.6 (C-1), 54.2

(C-1’), 54.8 (C-6), 64.4 (2CH₂O), 66.0 (C-2), 66.5 (C-5), 67.2 (C-4),

71.3 (C-5’’), 72.5 (C-3’), 76.1 (C-3), 81.7 (OCH₂adamantane), 115.0,

117.0, 119.3 (CHarm), 131.8, 142.7, 142.8 (Cq Carm), 176.0 ppm (C=

O); IR (thin film): n˜ =3322, 2902, 2848, 1654, 1508, 1287,

1069 cm^À1; LC–MS: t_R=7.10 min (linear gradient 10!90% B); ESI-

MS: m/z=619.3 [M+H]⁺, 1237.4 [2M+H]⁺; HRMS [QTOF, MH⁺]

m/z calculated for C₃₃H₅₁N₂O₉619.35891, found 619.35883.

10!50% B); ESI-MS: m/z=397.0 [M+H]⁺, 793.0 [2M+H]⁺; HRMS

[QTOF, MH⁺] m/z calculated for C₁₈H₂₅N₂O₈397.16054, found

397.16049.

Compound 58: The oxazolidine in compound 57 was hydrolyzed

according to the saponification procedure described above. Yield

0.027 g (72 mmol, 74%); R_f=0.35 (EtOH/Et₂O/NH₄OH 3:6:1, v/v/v).

½a²⁰=12.8 (c=0.53 in MeOH); ¹H NMR (400 MHz, D₂O): d=2.64

D

(dd, J=6.0, 14.0 Hz, 1H, H-1’a), 2.66 (dd, J=6.0, 13.2 Hz, 1H, H-1a),

2.73 (dd, J=5.4, 13.5 Hz, 1H, H-1b), 2.97 (m, 1H, H-5), 2.99 (dd, J=

4.4, 14.0 Hz, 1H, H-1’b), 3.32 (t, J=9.6 Hz, 1H, H-3), 3.47 (dt, J=5.6,

9.6 Hz, 1H, H-2), 3.59 (dd, J=5.7, 9.8 Hz, 1H, H-4), 3.60–3.64 (m,

1H, H-2’), 3.77 (dd, J=6.0, 12.0 Hz, 2H, H₂-6), 4.32 (s, 4H, 2H₂eth-

ylene), 4.64 (d, J=8.0 Hz, 1H, H-3’), 6.92–6.98 ppm (m, 3H, Harm);

¹³C NMR (100 MHz, D₂O): d=49.0 (C-1), 53.2 (C-1’), 55.4 (C-2’), 56.0

(C-6), 64.5 (C-5), 64.6 (2CH₂O), 68.5 (C-2), 70.0 (C-4), 71.6 (C-3’),

74.4 (C-3), 115.5, 117.7, 120.0 (CHarm), 132.8, 145.3, 143.5 ppm (Cq

Carm); IR (thin film): n˜ =3289, 2927, 1672, 1508, 1287, 1201, 1135,

1067, 1046 cm^À1; LC–MS: t_R=3.84 min (linear gradient 0!50% B);

ESI-MS: m/z=371.0 [M+H]⁺, 741.41 [2M+H]⁺; HRMS [QTOF, MH⁺

] m/z calculated for C₁₇H₂₇N₂O₇371.18128, found 371.18131.

Compound 12: Compound 9 was reacted with 52 according to the

general condensation protocol described above. Yield 0.017 g

(33 mmol, 77%). ½a²⁰=15.1 (c=0.33 in MeOH); H NMR (400 MHz,

1

D

D₂O): d=0.89 (t, J=6.9 Hz, 3H, CH₃), 1.01–1.16 (m, 2H, 1H₂nona-

noic amide), 1.21–1.33 (m, 8H, 4H₂nonanoic amide), 1.37–1.47

(m, 2H, 1H₂nonanoic amide), 2.22 (td, J=3.3, 7.2 Hz, 2H, H₂-2’’),

3.19 (t, J=11.9 Hz, 1H, H-1a), 3.26 (brd, J=9.4 Hz, 1H, H-5), 3.48–

3.55 (m, 1H, H-1’a), 3.55 (t, J=9.4 Hz, 1H, H-3), 3.62 (dd, J=4.7,

12.3 Hz, 1H, H-1b), 3.74 (t, J=9.9 Hz, 1H, H-4), 3.82–3.90 (m, 2H, H-

1’b, H-2), 4.05 (dd, J=2.6, 12.4 Hz, 1H, H-6a), 4.13 (d, J=13.5 Hz,

1H, H-6b), 4.34 (brs, 4H, 2H₂ethylene), 4.58 (td, J=2.9, 9.2 Hz,

1H, H-2’), 4.99 (d, J=3.4 Hz, 1H, H-3’), 6.93–7.05 ppm (m, 3H,

Harm); ¹³C NMR (100 MHz, D₂O): d=13.5 (CH₃), 22.1, 25.1 28.1, 28.2,

28.4, 31.2, 35.6 (CH₂nonanoic amide), 50.7 (C-2’), 53.5 (C-1), 54.1 (C-

1’), 54.4 (C-6), 64.6 (2CH₂O), 65.7 (C-2), 66.6 (C-5), 67.0 (C-4), 72.7

(C-3’), 75.9 (C-3), 114.9, 117.3, 119.4 (CHarm), 133.6, 142.8, 142.9 (Cq

Carm), 177.6 ppm (C=O); IR (thin film): n˜ =3324, 2927, 2854, 1670,

1508, 1287, 1200, 1136, 1068 cm^À1; LC–MS: t_R=9.00 min (linear gra-

dient 10!50% B); ESI-MS: m/z=511.3 [M+H]⁺, 1021.1 [2M+H]⁺;

HRMS [QTOF, MH⁺] m/z calculated for C₂₆H₄₃N₂O₈511.30139, found

511.30099.

Compound 14: Compound 58 was reacted with 10 according to

the general condensation protocol described above. Yield 0.005 g

(7 mmol, 29%). ½a²⁰=9.7 (c=0.21 in MeOH); ¹H NMR (400 MHz,

D

D₂O): d=1.30–1.34 (m, 2H, H₂-4’’), 1.41–1.50 (m, 2H, H₂-3’’), 1.53

(brs, 6H, H₂adamantane), 1.66–1.77 (m, 6H, H₂adamantane), 1.98

(brs, 3H CH adamantane), 2.25 (m, 2H, H₂-2’’), 3.04 (s, 2H, H₂ada-

mantane), 3.41 (t. J=6.2 Hz, H₂-5’’), 3.53 (t, J=4.9 Hz, 2H, H₂-1),

3.73 (brs, 2H, H₂-1’), 3.83 (brd, J=5.7 Hz, 1H, H-3), 3.93 (brs, 1H,

H-5), 3.98–4.05 (m, 2H, H-2, H-4), 4.09–4.17 (m, 2H, H₂-6), 4.31 (s,

4H, 2H₂ethylene), 4.65 (brs, 1H, H-2’), 4.96 (d, J=2.7 Hz, 1H, H-

3’), 6.90–7.01 ppm (m, 3H, Harm); ¹³C NMR (100 MHz, D₂O): d=

21.1 (C-3’’), 27.7 (C-4’’), 28.0 (CH adamantane), 35.4 (C-2’’), 36.7

(CH₂adamantane), 39.3 (CH₂adamantane), 50.4 (C-2’), 52.9 (C-1),

56.3 (C-1’), 63.4 (C-5), 64.5 (2CH₂O), 66.8, 69.3 (C-2, C-4), 71.0 (C-

5’’), 72.5 (C-3’), 81.5 (CH₂adamantane), 114.8, 117.3, 119.2 ppm

(CHarm); IR (thin film): n˜ =3325, 1635, 1201, 1145, 1068 cm^À1; LC–

MS: t_R=7.08 min (linear gradient 10!90% B); ESI-MS: m/z=619.4

[M+H]⁺, 1237.1 [2M+H]⁺; HRMS [QTOF, MH⁺] m/z calculated for

C₃₃H₅₁N₂O₉619.35891, found 619.35889.

Compound 13: Compound 9 was reacted with 55 according to the

general condensation protocol described above. Yield 0.020 g

(30 mmol, 71%). ½a²⁰=13.7 (c=0.52 in MeOH); H NMR (400 MHz,

1

D

D₂O): d=2.69 (t, J=5.8 Hz, 2H, H₂propanoic acid), 3.17 (t, J=

11.9 Hz, 1H, H-1a), 3.27 (brd, J=10.4 Hz, 1H, H-5), 3.49 (dd, J=8.8,

13.6 Hz, 1H, H-1’a), 3.53 (t, J=9.4 Hz, 1H, H-3), 3.61 (dd, J=4.9,

12.4 Hz, 1H, H-1b), 3.73 (t, J=9.9 Hz, 1H, H-4), 3.80–3.87 (m, 5H,

OMe, H-1’b, H-2), 4.03 (dd, J=3.1, 13.5 Hz, 1H, H-6a), 4.09 (dd, J=

2.9, 13.5 Hz, 1H, H-6b), 4.12 (t, J=5.8 Hz, 2H, H₂propanoic acid),

4.20 (m, 4H, 2H₂ethylene), 4.62 (td, J=3.2, 9.2 Hz, 1H, H-2’), 4.96

(d, J=3.8 Hz, 1H, H-3’), 6.86–7.054 ppm (m, 7H, Harm); ¹³C NMR

(100 MHz, D₂O): d=35.8 (CH₂propanoic acid), 50.9 (C-2’), 53.6 (C-1),

54.1 (C-1’), 54.4 (C-6), 56.0 (OMe), 64.5 (2CH₂O), 65.3 (CH₂propa-

noic acid), 65.7 (C-2), 66.8 (C-5), 67.0 (C-4), 72.6 (C-3’), 75.8 (C-3),

114.9, 115.2, 116.5, 116.7, 117.3, 119.5 (CHarm), 133.3, 142.8, 142.9,

152.3, 153.7 (Cq Carm), 174.3 ppm (C=O); IR (thin film): n˜ =3312,

1668, 1508, 1288, 1202, 1136, 1034 cm^À1; LC–MS: t_R=6.46 min

(linear gradient 10!50% B); ESI-MS: m/z=549.2 [M+H]⁺, 1097.0

[2M+H]⁺; HRMS [QTOF, MH⁺] m/z calculated for C₂₇H₃₇N₂O₁₀

549.24427, found 549.24407.

Compound 15: Compound 58 was reacted with 52 according to

the general condensation protocol described above. Yield 0.004 g

(6 mmol, 25%). ½a²⁰=17.6 (c=0.08 MeOH); ¹H NMR (400 MHz,

D

D₂O): d=0.89 (t, J=6.9 Hz, 3H, CH₃), 0.97–1.33 (m, 10H, 5H₂non-

anoic amide), 1.36–1.46 (m, 2H, 1H₂nonanoic amide), 2.16–2.29

(m, 2H, H₂-2’’), 3.53 (d, J=5.1 Hz, 2H, H₂-1), 3.72 (brs, 2H, H₂-1’),

3.82 (brs, 1H, H-3), 3.91 (brs, 1H, H-5), 3.99–4.09 (m, 2H, H-2, H-4),

4.11–4.17 (m, 2H, H₂-6), 4.35 (s, 4H, 2H₂ethylene), 4.63–4.66 (m,

1H, H-2’), 4.97 (d, J=3.0 Hz, 1H, H-3’), 6.92–7.01 ppm (m, 3H,

Harm); ¹³C NMR (100 MHz, D₂O): d=13.3 (CH₃), 22.1, 25.2 28.1, 28.3,

28.5, 29.7, 31.2, 35.6 (CH₂nonanoic amide), 50.5 (C-2’), 53.1 (C-1),

55.7 (C-6), 56.6 (C-1’), 63.6 (C-5), 64.7 (2CH₂O), 66.6 (C-2), 68.8 (C-

3), 69.2 (C-4), 72.3 (C-3’), 114.8, 117.4, 119.3 (CHarm), 133.9, 142.7,

142.9 (Cq Carm), 178.3 ppm (C=O); IR (thin film): n˜ =3267, 2927,

2856, 1670, 1508, 1286, 1199, 1136, 1066 cm^À1; LC–MS: t_R=

6.29 min (linear gradient 10!90% B); ESI-MS: m/z=511.3 [M+H]⁺

Compound 57: Compound 56 was reacted with mesylate 6 ac-

cording to the general procedure described above. Yield 0.038 g

(96 mmol, 39%); R_f=0.40 (MeOH/EtOAc/NH₄OH 40:60:5, v/v/v).

1

½a²⁰=28.8 (c=0.764 in MeOH); H NMR (400 MHz, MeOD): d=2.82

D

(brs, 2H, H₂-1), 3.06–3.23 (brm, 3H, H₂-1’, H-5), 3.41–3.73 (brm, 3H,

H-2, H-3, H-4), 3.83–3.97 (brm, 3H, H-2’, H₂-6), 4.24 (s, 4H, 2H₂

ethylene), 5.19 (d, 1H, J=5.4 Hz, 1H, H-3’), 6.86–6.70 ppm (m, 3H,

Harm); ¹³C NMR (100 MHz, MeOD): d=52.9 (C-1), 58.2 (C-6), 59.7

(C-2’), 59.9 (C-1’), 65.6 (2CH₂O), 66.4 (C-5), 70.8, 72.8, 74.8 (C-2, C-

3, C-4), 83.0 (C-3’), 116.1, 118.6, 120.1 (CHarm), 133.31, 145.3 ppm

(Cq Carm); IR (thin film): n˜ =3264, 2924, 1734, 1668, 1508, 1436,

1289, 1202, 1132, 1067 cm^À1; LC–MS: t_R=5.57 min (linear gradient

,

1021.3 [2M+H]⁺; HRMS [QTOF, MH⁺] m/z calculated for

C₂₆H₄₃N₂O₈511.30139, found 511.30114.

Compound 16: Compound 58 was reacted with 55 according to

the general condensation protocol described above. Yield 0.007 g

(10 mmol, 41%). ½a²⁰=11.8 (c=0.14 in MeOH); H NMR (400 MHz,

1

D

D₂O): d=2.64–2.75 (m, 2H, H₂propanoic acid), 3.50 (d, J=5.0 Hz,

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Full Papers

2H, H₂-1), 3.71 (brs, 2H, H₂-1’), 3.81 (brs, 1H, H-3), 3.84 (s, 3H,

OMe), 3.89 (brs, 1H, H-5), 3.93 (q, J=5.4 Hz, 1H, H-2), 4.02 (brs,

1H, H-4), 4.05–4.13 (m, 4H, H₂propanoic acid, H₂-6), 4.16–4.23 (m,

4H, 2H₂ethylene), 4.68 (m, 1H, H-2’), 4.94 (d, J=3.3 Hz, 1H, H-

3’), 6.85–7.01 ppm (m, 7H, Harm); ¹³C NMR (100 MHz, D₂O): d=

35.9 (CH₂propanoic acid), 50.7 (C-2’), 53.0 (C-1), 56.0 (OMe), 56.6

(C-1’), 57.3 (C-6), 63.5 (C-5), 64.5 (2CH₂O), 65.4 (CH₂propanoic

acid), 66.7 (C-2), 69.3 (C-4), 72.3 (C-3’), 114.8, 115.2, 116.6, 117.3,

119.3 (CHarm), 133.7, 142.7, 142.9, 152.3, 153.7 (Cq Carm),

174.8 ppm (C=O); IR (thin film): n˜ =3325, 1635, 1508, 1201, 1143,

1066 cm^À1; LC–MS: t_R=5.01 min (linear gradient 10!90% B); ESI-

MS: m/z=549.2 [M+H]⁺, 1096.9 [2M+H]⁺; HRMS [QTOF, MH⁺]

m/z calculated for C₂₇H₃₇N₂O₁₀549.24427, found 549.24410.

Compound 19: Compound 61 was reacted with 55 according to

the general condensation protocol described above. Yield 0.011 g

(20 mmol, 27%); ¹H NMR (400 MHz, CD₃CN): d=2.64 (m, 2H, H₂

propanoic acid), 2.96–3.67 (m, 6H, H₂-1, H₂-1’, H-3, H-5), 3.74 (s, 3H,

OMe), 3.83–4.10 (m, 6H, H-2, H-4, H₂-6, H₂propanoic acid), 4.21 (m,

4H, 2H₂ethylene), 4.47 (m, 1H, H-2’), 4.82 (m, 1H, H-3’), 6.76–

6.88 ppm (m, 7H, Harm); IR (thin film): n˜ =3297, 2927, 2856, 1675,

1287, 1203, 1179, 1128, 1012 cm^À1; LC–MS: t_R=5.85 min (linear gra-

dient 10!60% B); ESI-MS: m/z=549.3 [M+H]⁺, 1118.9 [2M+Na]⁺;

HRMS [QTOF, MH⁺] m/z calculated for C₂₇H₃₇N₂O₁₀549.24427, found

549.24395.

Compound 63: Compound 62 was reacted with mesylate 6 ac-

cording to the general procedure described above. Yield 0.055 g

(138 mmol, 55%); R_f=0.30 (MeOH/EtOAc/NH₄OH 20:80:5, v/v/v).

Compound 60: Compound 59 was reacted with mesylate 6 ac-

cording to the general procedure described above. Yield 0.056 g

(141 mmol, 65%); R_f=0.65 (EtOAc/tBuOH/AcOH/H₂O, 1:1:1:1, v/v/v/

½a²⁰=66.5 (c=0.99 in MeOH); H NMR (400 MHz, MeOD): d=2.61

1

D

(dd, J=7.2, 12.3 Hz, 1H, H-1a), 2.69 (dd, J=4.0, 12.3 Hz, 1H, H-1b),

v). ½a²⁰=37.5 (c=1.12 in MeOH); ¹H NMR (400 MHz, MeOD): d=

2.99–3.06 (m, 2H, H-1’a, H-5), 3.03 (dd, J=8.5, 13.3 Hz, 1H, H-1’b),

3.56 (dd, J=3.3, 7.1 Hz, 1H, H-3), 3.71 (dd, J=4.9, 11.6 Hz, 1H, H-

6a), 3.75 (m, 1H, H-2), 3.78 (dd, J=5.3, 11.6 Hz, 1H, H-6b), 3.84–

3.90 (m, 2H, H-2’, H-4), 4.24 (s, 4H, 2H₂ethylene), 5.13 (d, J=

6.0 Hz, 1H, H-3’), 6.84–6.91 ppm (m, 3H, Harm); ¹³C NMR (100 MHz,

MeOD): d=53.3 (C-1), 59.2 (C-1’, C-6), 59.9 (C-2’), 65.6 (2CH₂O),

66.3 (C-5), 68.9 (C-4), 69.8 (C-2), 73.1 (C-3), 82.7 (C-3’), 116.1, 118.6,

120.1 (CHarm), 133.5, 145.3, 145.6 (Cq Carm), 161.4 ppm (C=O); IR

(thin film): n˜ =3300, 2927, 2362, 1735, 1652, 1593, 1510, 1396,

1290, 1018 cm^À1; LC–MS: t_R=5.56 min (linear gradient 10!50%

B); ESI-MS: m/z=396.9 [M+H]⁺, 793.1 [2M+H]⁺; HRMS [QTOF,

MH⁺] m/z calculated for C₁₈H₂₅N₂O₈397.16054, found 397.16045.

D

2.15 (dd, J=9.8, 11.3 Hz, 1H, H-1a), 2.46 (q, J=3.0 Hz, 1H, H-5),

2.63 (dd, J=7.1, 13.4 Hz, 1H, H-1’a), 2.94 (dd, J=4.6, 11.6 Hz, 1H,

H-1b), 3.06 (dd, J=6.6, 13.5 Hz, 1H, H-1’b), 3.28 (dd, J=3.2, 8.8 Hz,

1H, H-3), 3.74 (td, J=4.6, 9.1 Hz, 1H, H-2), 3.78–3.86 (m, 3H, H-2’,

H₂-6), 3.97 (dd, J=2.4, 2.8 Hz, 1H, H-4), 4.23 (s, 4H, 2H₂ethylene),

5.25 (d, J=5.7 Hz, 1H, H-3’), 6.84–6.91 ppm (m, 3H, Harm);

¹³C NMR (100 MHz, MeOD): d=58.2 (C-1’, C-1), 60.6 (C-2’), 62.6 (C-

6), 65.6 (2CH₂O), 66.5 (C-5), 68.6 (C-2), 72.6 (C-4), 76.6 (C-3), 82.9

(C-3’), 116.0, 118.6, 120.1 (CHarm), 133.6, 145.2, 145.4 (Cq Carm),

161.4 ppm (C=O); IR (thin film): n˜ =3371, 2931, 1735, 1643, 1589,

1512, 1434, 1288, 1211, 1172, 1049 cm^À1; LC–MS: t_R=7.78 min

(linear gradient 0!50% B); ESI-MS: m/z=397.2 [M+H]⁺, 793.6

[2M+H]⁺; HRMS [QTOF, MH⁺] m/z calculated for C₁₈H₂₅N₂O₈

397.16054, found 397.16014.

Compound 64: The oxazolidine in compound 63 was hydrolyzed

according to the saponification procedure described above; R_f=

0.35 (EtOH/Et₂O/NH₄OH 3:6:1, v/v/v). ½a²⁰=15.18 (c=0.33 in

D

1

MeOH); H NMR (400 MHz, D₂O): d=2.64 (dd, J=5.7, 14.0 Hz, 1H,

Compound 61: The oxazolidine in compound 60 was hydrolyzed

according to the saponification procedure described above. The

obtained imine 61 was immediately condensed with the hydroxy-

succinimide esters 10, 42 and 55 as described in the general con-

densing procedure; LC–MS: t_R=3.65 min (linear gradient 0!50%

B); ESI-MS: m/z=371.1 [M+H]⁺.

H-1’a), 2.66 (dd, J=5.9, 13.3 Hz, 1H, H-1a), 2.73 (dd, J=5.4, 13.5 Hz,

1H, H-1b), 2.97 (m, Hz, 1H, H-5), 2.98 (dd, J=4.8, 13.9 Hz, 1H, H-

1’b), 3.32 (t, J=9.4 Hz, 1H, H-3), 3.47 (td, J=5.5, 9.9 Hz, 1H, H-2),

3.59 (dd, J=5.7, 9.8 Hz, 1H, H-4), 3.63 (m, 1H, H-2’), 3.77 (d, J=

6.4 Hz, 2H, H₂-6), 4.32 (brs, 4H, 2H₂ethylene), 4.64 (d, J=8.0 Hz,

1H, H-3’), 6.89–7.03 ppm (m, 3H, Harm); ¹³C NMR (100 MHz, D₂O):

d=49.0 (C-1), 53.2 (C-1’), 55.4 (C-2’), 56.0 (C-6), 64.5 (C-5), 64.6 (2

CH₂O), 68.5 (C-2), 70.0 (C-4), 71.6 (C-3’), 74.4 (C-3), 115.5, 117.7,

120.0 (CHarm), 132.8, 143.3, 143.5 ppm (Cq Carm); IR (thin film):

n˜ =3324, 2927, 2854, 1670, 1508, 1287, 1200, 1136, 1068 cm^À1; LC–

MS: t_R=3.72 min (linear gradient 0!50% B); ESI-MS: m/z=371.1

[M+H]⁺; HRMS [QTOF, MH⁺] m/z calculated for C₁₇H₂₇N₂O₇

371.18128, found 371.18131.

Compound 17: Compound 61 was reacted with 10 according to

the general condensation protocol described above. Yield 0.017 g

(28 mmol, 38%). ½a²⁰=9.3 (c=0.11 in MeOH); ¹H NMR (400 MHz,

D

CD₃CN): d=1.24–1.38 (m, 4H, H₂-4’’, H₂-3’’), 1.52 (brs, 6H, H₂ada-

mantane), 1.68–1.75 (m, 6H, H₂adamantane), 1.94 (brs, 3H CH ada-

mantane), 2.28 (m, 2H, H₂-2’’), 2.97 (s, 2H, H₂adamantane), 3.01–

3.67 (m, 8H, H₂-5’’, H₂-1, H₂-1’, H-3, H-5), 3.87–4.16 (m, 8H, H-2, H-4,

H₂-6, 2H₂ethylene), 4.48 (brs, 1H, H-2’), 4.85 (d, J=3.2 Hz, 1H, H-

3’), 6.82–6.84 ppm (m, 3H, Harm); IR (thin film): n˜ =3242, 2901,

2849, 1668, 1506, 1287, 1202, 1181, 1134, 1070, 1020 cm^À1; LC–MS:

t_R=9.77 min (linear gradient 10!60% B); ESI-MS: m/z=619.4 [M+

H]⁺, 1259.3 [2M+H]⁺; HRMS [QTOF, MH⁺] m/z calculated for

C₃₃H₅₁N₂O₉619.35891, found 619.35878.

Compound 20: Compound 64 was reacted with 10 according to

the general condensation protocol described above. Yield 0.017 g

(28 mmol, 60%); ¹H NMR (400 MHz, CD₃CN): d=1.27–1.36 (m, 2H,

H₂-4’’), 1.42–1.48 (m, 2H, H₂-3’’), 1.52 (brs, 6H, H₂adamantane),

1.64–1.75 (m, 6H, H₂adamantane), 1.97 (brs, 3H CH adamantane),

2.16 (t, J=7.6 Hz, 2H, H₂-2’’), 2.93 (s, 2H, H₂adamantane), 3.19–

3.24 (m, 2H, H-1’a, H-5), 3.28 (t, J=6.1 Hz, H₂-5’’), 3.32–3.35 (m 1H,

H-1a), 3.63 (dd, J=2.3, 12.6 Hz, 1H, H-1b), 3.71 (dd, J=10.6,

13.3 Hz, 1H, H-1’b), 3.89 (t, J=3.5 Hz, 1H, H-4), 3.94–4.01 (m, 4H,

H-2, H-3, H₂-6), 4.22 (s, 4H, 2H₂ethylene), 4.36 (brs, 1H, H-2’),

4.77 (d, J=3.3 Hz, 1H, H-3’), 6.80–6.89 ppm (m, 3H, Harm);

¹³C NMR (100 MHz, CD₃CN): d=23.2 (C-3’’), 29.3 (CH adamantane),

29.6 (C-4’’), 34.8 (Cq adamantane), 36.0 (C-2’’), 37.9 (CH₂adaman-

tane), 40.5 (CH₂adamantane), 52.3 (C-2’), 53.4 (C-1), 55.0 (C-6), 57.7

(C-1’), 64.1 (C-4), 64.6 (C-5), 65.4 (2CH₂O), 66.6 (C-2), 68.6 (C-3),

71.7 (C-5’’), 72.5 (C-3’), 82.6 (CH₂adamantane), 115.9, 118.0, 119.8

(CHarm), 134.9, 144.4, 144.5 ppm (Cq Carm); IR (thin film): n˜ =3222,

Compound 18: Compound 61 was reacted with 52 according to

the general condensation protocol described above. Yield 0.010 g

(20 mmol, 27%); ¹H NMR (400 MHz, CD₃CN): d=0.88 (t, J=7.0 Hz,

3H, CH₃), 1.07–1.46 (m, 12H, 6H₂nonanoic amide), 2.18 (m, 2H,

H₂-2’’), 2.94–3.67 (m, 6H, H₂-1, H₂-1’, H-3, H-5), 3.82–4.04 (m, 3H, H-

2, H₂-6)), 4.13 (brs, 1H H-4), 4.22 (s, 4H, 2H₂ethylene), 4.37 (brs,

1H, H-2’), 4.80 (brs, 1H, H-3’), 6.76–6.98 ppm (m, 3H, Harm); IR

(thin film): n˜ =3298, 2927, 2858, 1675, 1287, 1202, 1134, 1069,

1020 cm^À1; LC–MS: t_R=8.17 min (linear gradient 10!60% B); ESI-

MS: m/z=511.3 [M+H]⁺, 1043.1 [2M+Na]⁺; HRMS [QTOF, MH⁺]

m/z calculated for C₂₆H₄₃N₂O₈511.30139, found 511.30108.

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2904, 2850, 1662, 1436, 1287, 1200, 1179, 1066, 1017 cm^À1; LC–MS:

t_R=9.82 min (linear gradient 10!60% B); ESI-MS: m/z=619.3 [M+

H]⁺, 1237.3 [2M+H]⁺, 1259.3 [2M+Na]⁺; HRMS [QTOF, MH⁺] m/z

calculated for C₃₃H₅₁N₂O₉619.35891, found 619.35877.

134.7, 144.4, 144.5, 153.3, 155.2 ppm (Cq Carm); IR (thin film): n˜ =

3284, 2927, 2859, 1675, 1290, 1229, 1203, 1181, 1132, 1067,

1025 cm^À1; LC–MS: t_R=5.86 min (linear gradient 10!60% B); ESI-

MS: m/z=549.1 [M+H]⁺, 1096.7 [2M+H]⁺; HRMS [QTOF, MH⁺]

m/z calculated for C₂₇H₃₇N₂O₁₀549.24427, found 549.24394.

Compound 21: Compound 64 was reacted with 52 according to

the general condensation protocol described above. Yield 0.013 g

(25 mmol, 53%); ¹H NMR (400 MHz, CD₃CN): d=0.88 (t, J=6.9 Hz,

3H, CH₃), 1.08–1.13 (m, 2H, H₂nonanoic amide), 1.19–1.30 (m, 2H,

4H₂nonanoic amide), 1.35–1.42 (m, 2H, 1H₂nonanoic amide),

2.12 (t, J=7.5 Hz, 2H, H₂-2’’), 3.19–3.35 (m, 3H, H-1’a, H-5, H-1a),

3.63 (dd, J=2.0, 12.8 Hz, 1H, H-1b), 3.71 (dd, J=10.6, 13.2 Hz, 1H,

H-1’b), 3.89 (dd, J=3.2, 3.6 Hz, 1H, H-4), 3.95–4.01 (m, 4H, H-2, H-3,

H₂-6), 4.22 (s, 4H, 2H₂ethylene), 4.36 (brs, 1H, H-2’), 4.77 (d, J=

3.2 Hz, 1H, H-3’), 6.81–6.89 ppm (m, 3H, Harm); ¹³C NMR (100 MHz,

CD₃CN): d=14.4 (CH₃), 23.4, 26.3 29.7, 29.8, 30.0, 32.6, 36.3 (CH₂

nonanoic amide), 52.2 (C-2’), 53.4 (C-1), 55.0 (C-6), 57.9 (C-1’), 64.1

(C-4), 64.6 (C-5), 65.3 (2CH₂O), 66.6 (C-2), 68.6 (C-3), 72.5 (C-3’),

115.9, 118.0, 119.8 (CHarm), 134.9, 144.3, 144.5 (Cq Carm),

173.7 ppm (C=O); IR (thin film): n˜ =3293, 2928, 2854, 1675, 1506,

1287, 1202, 1184, 1130, 1068, 1020 cm^À1; LC–MS: t_R=8.11 min

(linear gradient 10!60% B); ESI-MS: m/z=511.1 [M+H]⁺, 1020.8

[2M+H]⁺; HRMS [QTOF, MH⁺] m/z calculated for C₂₆H₄₃N₂O₈

511.30139, found 511.30106.

General procedure for Pd/C catalyzed hydrogenolysis. The per-

benzylated iminosugar (7.5 mmol - 8 mmol) was dissolved in a mix-

ture of 2m HCl (aq.) in EtOH (0.05m, 3/1, v/v) and transferred to

a Parr high-pressure hydrogenation flask. The atmosphere was ex-

changed to argon after which a catalytic amount of palladium on

carbon (~0.1 equiv, 10 wt% on carbon) was added. The flask was

put under reduced pressure and ventilated with hydrogen gas.

This procedure was repeated twice after which the pressure was

adjusted to 4.5–5 bar hydrogen pressure. The reaction was allowed

to react for 24 h while mechanically shaken and the pressure being

kept at the value initially set. The mixture was filtered over a glass

microfiber filter, followed by rinsing the filter with EtOH. The mix-

ture was concentrated under reduced pressure followed by several

co-evaporation steps with EtOH and MeOH to yield the deprotect-

ed iminosugar as hydrochloride salt (Scheme 4).

2,3,5-Tri-O-benzyl-d-lyxitol (66): 2,3,5-Tri-O-benzyl-d-lyxono-1,4-

lactone (65, 11.9 g, 28.4 mmol) in THF (120 mL) was slowly added

to a solution of LiAlH₄(2.6 g, 68 mmol) in THF (120 mL) at 08C. The

reaction mixture was stirred for 1.5 h at 08C, after which the reac-

tion was quenched with EtOAc. Sodium potassium tartrate (sat.

aq.) was slowly added and the mixture was stirred for 30 min

before EtOAc was added and the layers separated. The organic

layer was washed with NaHCO₃(sat. aq.) and brine before being

dried over anhydrous MgSO₄, filtered and concentrated under re-

duced pressure. The residue was purified by flash chromatography

Compound 22: Compound 64 was reacted with 55 according to

the general condensation protocol described above. Yield 0.009 g

(16 mmol, 34%); ¹H NMR (400 MHz, CD₃CN): d=2.54–2.62 (m, 2H,

H₂propanoic acid), 3.21 (brs, 1H, H-1’a), 3.28–3.33 (m, 2H, H-5, H-

1a), 3.63 (d, J=12.3 Hz, 1H, H-1b), 3.73 (m, 4H, H-1’b, OMe), 3.89

(brs, 1H, H-3), 3.97–4.03 (m, 6H, H-2, H-4, H₂-6, H₂propanoic acid),

4.20 (s, 4H, 2H₂ethylene), 4.39 (brs, 1H, H-2’), 4.79 (brs, 1H, H-

3’), 6.78–6.89 ppm (m, 7H, Harm); ¹³C NMR (100 MHz, CD₃CN): d=

36.5 (CH₂propanoic acid), 52.3 (C-2’), 53.6 (C-1), 55.1 (C-6), 56.2

(OMe), 58.0 (C-1’), 64.1 (C-4), 64.6 (C-5), 65.3 (2CH₂O), 66.7 (C-2),

68.6 (C-3), 72.5 (C-3’), 115.6, 115.9, 116.6, 118.0, 119.8 (CHarm),

(50% EtOAc/n-pentane) yielding the title compound (10.7 g,

20

D

25.4 mmol, 89% yield); R_f=0.6 (EtOAc/n-pentane 1:1, v/v). ½a

=

1

À18.98 (c=1.00, CHCl₃); H NMR (400 MHz, CDCl₃): d=2.49 (s, 2H,

OH-1, OH-4), 3.46 (dd, J=9.5, 6.1 Hz, 1H, H-5a), 3.53 (dd, J=9.4,

Scheme 4. Reagents and conditions: a) LiAlH₄, THF, 08C; b) 1) PH₃P, I₂, imidazole, DMF, À358C, 2) PhNH₂, 558C; c) H₂, Pd/C, HCl, EtOH; d) 6, K₂CO₃, DMF, 808C;

e) LiOH, dioxane/H₂O, microwave, 1658C; f) 10, 52 or 55, DiPEA, DMF; g) NaBH₄, EtOH; h) 1) MsCl, pyridine, 08C, 2) PhNH₂, 558C.

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6.1 Hz, 1H, H-5b), 3.71–3.68 (m, 1H, H-2), 3.76–3.71 (m, 1H, H-1a),

3.79 (dd, J=6.4, 2.1 Hz, 1H, H-3), 3.90–3.82 (m, 1H, H-1b), 4.00 (td,

J=6.1, 2.1 Hz, 1H, H-4), 4.46 (d, J=11.9 Hz, 1H, HH Bn), 4.51 (d, J=

12.0 Hz, 1H, HH Bn), 4.52 (d, J=11.1 Hz, 1H, HH Bn), 4.61 (s, 2H, H₂

Bn), 4.73 (d, J=11.1 Hz, 1H, HH Bn), 7.24–7.39 ppm (m, 15H, Harm

Bn); ¹³C NMR (100 MHz, CDCl₃): d=60.6 (C-1), 69.8 (C-4), 71.3 (C-5),

72.5, 73.5, 74.4 (3CH₂Bn), 77.1 (C-3), 79.6 (C-2), 127.9–128.6

(CHarm Bn), 137.9, 137.9, 138.0 ppm (Cq Bn); IR (thin film): n˜ =

3061, 3030, 2920, 2864, 1497, 1454, 1395, 1362, 1327, 1308, 1265,

1246, 1207, 1090, 1049, 1026 cm^À1; HRMS [QTOF, MH⁺] m/z calcu-

lated for C₂₆H₃₀O₅423.21660, found 423.21629.

Compound 69: Compound 68 was reacted with mesylate 6 ac-

cording to the general procedure described above. Yield 0.084 g

(230 mmol, 58%); R_f=0.50 (MeOH/EtOAc/NH₄OH 40:60:5, v/v/v).

½a²⁰=21.8 (c=0.96 in MeOH); H NMR (400 MHz, MeOD): d=2.56

1

D

(dd, J=5.3, 10.1 Hz, 1H, H-1a), 2.71 (dd, J=5.8, 12.4 Hz, 1H, H-1’a),

2.77 (dt, 1H, J=4.3, 7.3 Hz, H-4), 2.89 (dd, J=3.2, 10.4 Hz, 1H, H-

1b), 2.91 (dd, J=8.4, 12.4 Hz, 1H, H-1’b), 3.67 (dd, J=4.0, 11.2 Hz,

1H, H-5a), 3.73 (ddd, J=4.8, 6.0, 8.4 Hz, 1H, H-2’), 3.74 (dd, J=4.4,

11.2 Hz, 1H, H-5b), 4.08 (dt, J=3.3, 5.1 Hz, 1H, H-2), 4.22 (dd, J=

4.8, 6.4 Hz, 1H, H-3), 4.23 (s, 4H, 2H₂ethylene), 5.27 (d, J=5.1 Hz,

1H, H-3’), 6.83–6.90 ppm (m, 3H, Harm); ¹³C NMR (100 MHz,

MeOD): d=59.8 (C-1), 60.8 (C-2’), 60.8 (C-1’), 61.4 (C-5), 65.6 (2

CH₂O), 68.3 (C-4), 71.9 (C-2), 73.5 (C-3), 82.9 (C-3’), 115.9, 118.6,

119.9 (CHarm), 133.9, 145.2, 145.3 (Cq Carm), 161.4 ppm (C=O); LC–

MS: t_R=9.00 min (linear gradient 0!90% B); ESI-MS: m/z=366.9

[M+H]⁺, 733.0 [2M+H]⁺; HRMS [QTOF, MH⁺] m/z calculated for

C₁₇H₂₃N₂O₇367.14998, found 367.15012.

1,4-Dideoxy-1,4-benzylimino-2,3,5-tri-O-benzyl-d-lyxitol

(67):

2,3,5-Tri-O-benzyl-d-lyxitol (66, 5.30 g, 12.5 mmol), triphenylphos-

phine (7.5 g, 28.8 mmol) and imidazole (2.6 g, 37.5 mmol) were co-

evaporated thrice with dry toluene before being dissolved in

CH₂Cl₂(125 mL) and cooled to À308C. Iodine (7.6 g, 30 mmol) was

slowly added and the reaction mixture stirred for 3 days at À358C,

then 1 day at À258C. The solution was concentrated under re-

duced pressure, dry toluene (125 mL) was added and the mixture

held at reflux for 2 h. The reaction mixture was diluted with Et₂O,

washed with Na₂S₂O₃(sat. aq.) and brine, dried over anhydrous

MgSO₄, filtered and concentrated under reduced pressure. The resi-

due was co-evaporated with Et₂O to get rid of the residual toluene

and then dissolved in Et₂O after which it was filtered to remove

most of the Ph₃PO. The crude 1,4-dideoxy-1,4-diiodo-2,3,5-tri-O-

benzyl-l-ribitol (~12.5 mmol) was dissolved in benzylamine (41 mL,

375 mmol) and stirred for 2 days at 558C. The mixture was diluted

with EtOAc, washed with 1m HCl (aq.), NaHCO₃(sat. aq.) and brine,

dried over anhydrous MgSO₄, filtered and concentrated under re-

duced pressure. The residue was purified by flash chromatography

(12.5–15% Et₂O/n-pentane) yielding the title compound (3.40 g,

6.80 mmol, 55% over two steps); R_f=0.55 (Et₂O/n-pentane 2:3, v/

Compound 70: The oxazolidine in compound 69 was hydrolyzed

according to the saponification procedure described above. The

obtained imine 70 was immediately condensed with the hydroxy-

succinimide esters 10, 42 and 55 as described in the general con-

densing procedure; LC–MS: t_R=3.63 min (linear gradient 0!50%

B); ESI-MS: m/z=341.0 [M+H]⁺, 681.3 [2M+H]⁺; HRMS [QTOF,

MH⁺] m/z calculated for C₁₆H₂₅N₂O₆341.17071, found 341.17078.

Compound 23: Compound 70 was reacted with 10 according to

the general condensation protocol described above. Yield 0.003 g

(5 mmol, 20%). ½a²⁰=4.3 (c=0.06 in MeOH); ¹H NMR (400 MHz,

D

D₂O): d=1.39 (brs, 2H, H₂-4’’), 1.45 (brs, 2H, H₂-3’’), 1.54 (brs, 6H,

H₂adamantane), 1.65–1.78 (m, 6H, H₂adamantane), 1.98 (brs, 3H

CH adamantane), 2.26 (brs, 2H, H₂-2’’), 3.05 (brs, 2H, H₂adaman-

tane), 3.37–3.60 (brm, 4H, H-1’a,H-1, H₂-5’’), 3.75–3.98 (brm, 3H, H-

1b, H-2, H-1’b), 4.08 (brs, 2H, H₂-5), 4.35 (brs, 4H, 2H₂ethylene),

4.53 (brs, 3H, H-2’, H-3, H-4), 4.94 (s, 1H, H-3’), 6.91–7.01 ppm (m,

3H, Harm); ¹³C NMR (100 MHz, CD₃CN): d=23.3 (C-3’’), 29.4 (CH

adamantane), 29.7 (C-4’’), 34.9 (Cq adamantane), 36.2 (C-2’’), 38.0

(CH₂adamantane), 40.5 (CH₂adamantane), 53.0 (C-2’), 58.0 (C-5),

59.6 (C-1’), 60.0 (C-1), 65.4 (2CH₂O), 70.0 (C-2), 71.5 (C-3, C-4), 71.8

(C-5’’), 73.3 (C-3’), 82.6 (OCH₂adamantane), 116.1, 118.0, 120.0

(CHarm), 134.4, 144.5, 144.6 (Cq Carm), 177.0 ppm (C=O); IR (thin

film): n˜ =3369, 1670, 1286, 1201, 1136 cm^À1; LC–MS: t_R=9.79 min

(linear gradient 10!60% B); ESI-MS: m/z=589.3 [M+H]⁺, 1177.3

[2M+H]⁺; HRMS [QTOF, MH⁺] m/z calculated for C₃₂H₄₉N₂O₈

589.34834, found 589.34833.

v).½a²⁰=À36.08 (c=1.00, CHCl₃); ¹H NMR (400 MHz, CDCl₃): d=

D

2.56 (dd, J=10.7, 6.1 Hz, 1H, H-1a), 3.07 (dd, J=10.7, 4.9 Hz, 1H,

H-1b), 3.17 (q, J=6.0 Hz, 1H, H-4), 3.59 (d, J=13.6 Hz, 1H, HH N-

Bn), 3.68 (dd, J=9.4, 6.0 Hz, 1H, H-5a), 3.91 (dd, J=9.4, 6.1 Hz, 1H,

H-5b), 3.95 (dt, J=6.1, 5.0 Hz, 1H, H-2), 4.05 (d, J=13.7 Hz, 1H, HH

N-Bn), 4.07 (t, J=5.3 Hz, 1H, H-3), 4.50 (s, 2H, HH Bn), 4.52 (d, J=

12.3 Hz, 1H, HH Bn), 4.54 (d, J=12.4 Hz, 1H, HH Bn), 4.61 (d, J=

12.1 Hz, 1H, HH Bn), 4.74 (d, J=12.1 Hz, 1H, CHH Bn), 7.14–

7.44 ppm (m, 20H, CHarm Bn); ¹³C NMR (100 MHz, CDCl₃): d=54.9

(C-1), 59.8 (CH₂N-Bn), 64.4 (C-4), 70.7 (C-5), 71.7 (CH₂Bn-2), 73.0

(CH₂Bn-3), 73.5 (CH₂Bn-5), 77.4 (C-2), 78.8 (C-3), 126.9–128.9

(CHarm Bn), 138.6, 138.7, 138.8, 139.4 ppm (Cq Bn); IR (thin film):

n˜ =3061, 3028, 2913, 2862, 2793, 1495, 1452, 1398, 1364, 1344,

1308, 1281, 1256, 1207, 1142, 1090, 1061, 1026 cm^À1; HRMS [QTOF,

MH⁺] m/z calculated for C₃₃H₃₅NO3 494.26897, found 494.26804.

Compound 24: Compound 70 was reacted with 52 according to

the general condensation protocol described above. Yield 0.013 g

(27 mmol, 36%); ¹H NMR (400 MHz, CD₃CN): d=0.89 (t, J=6.4 Hz,

3H, CH₃), 1.15–1.58 (m, 12H, 6H₂nonanoic amide), 2.28 (brs, 2H,

H₂-2’’), 3.27–3.33 (m, 2H, H-1’a, H-1a), 3.60–3.68 (m, 3H, H-1b, H-2,

H-1’b), 4.00 (brs, 2H, H₂-5), 4.22 (s, 4H, 2H₂ethylene), 4.39–4.46

(m, 3H, H-2’, H-3, H-4), 4.81 (brs, 1H, H-3’), 6.66–7.01 ppm (m, 3H,

Harm); ¹³C NMR (100 MHz, CD₃CN): d=14.4 (CH₃), 23.4, 26.3 29.7,

29.8, 30.0, 32.6, 36.5 (CH₂nonanoic amide), 53.1 (C-2’), 56.4 (C-5),

60.1 (C-1’), 60.5 (C-1), 65.4 (2CH₂O), 69.7 (C-2), 72.2 (C-3, C-4), 73.2

(C-3’), 116.1, 118.3, 120.0 (CHarm), 134.4, 144.4, 144.5 ppm (Cq

Carm); IR (thin film): n˜ =3369, 2900, 2848, 1670, 1508, 1286, 1201,

1136 cm^À1; LC–MS: t_R=8.16 min (linear gradient 10!60% B); ESI-

MS: m/z=481.2 [M+H]⁺, 960.7 [2M+H]⁺; HRMS [QTOF, MH⁺] m/z

calculated for C₂₅H₄₁N₂O₇481.29083, found 481.29060.

1,4-Dideoxy-1,4-imino-d-lyxitol hydrochloride (68): 1,4-Dideoxy-

1,4-benzylimino-2,3,5-tri-O-benzyl-d-lyxitol (67, 3.95 g, 8 mmol) was

subjected to the general hydrogenolysis procedure yielding the

title compound (1.32 g, 7.8 mmol, 98%). ½a²⁰=23.48 (c=1.00,

D

MeOH); ¹H NMR (600 MHz, MeOD): d=3.14 (dd, J=11.7, 7.3 Hz,

1H, H-1a), 3.42 (dd, J=11.7, 7.3 Hz, 1H, H-1b), 3.64 (dt, J=8.8,

4.4 Hz, 1H, H-4), 3.89 (dd, J=11.8, 8.9 Hz, 1H, H-5a), 3.94 (dd, J=

11.8, 4.6 Hz, 1H, H-5b), 4.21 (t, J=4.0 Hz, 1H, H-3), 4.40 ppm (td,

J=7.3, 4.0 Hz, 1H, H-2); ¹³C NMR (150 MHz, MeOD): d=48.5 (C-1),

59.3 (C-5), 64.5 (C-4), 71.3 (C-3), 71.8 ppm (C-2); IR (thin film): n˜ =

3404, 3221, 2976, 2930, 2891, 2783, 2733, 2716, 2666, 2583, 2480,

1601, 1460, 1412, 1350, 1287, 1269, 1202, 1115, 1040 cm^À1; HRMS

[QTOF, MH⁺] m/z calculated for C₅H₁₁NO₃134.08117, found:

134.08122.

Compound 25: Compound 70 was reacted with 55 according to

the general condensation protocol described above. Yield 0.036 g

1

(70 mmol, 91%); H NMR (400 MHz, D₂O): d=2.60 (brs, 2H, H₂-2’’),

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3.26–3.36 (m, 2H, H-1’a, H-1a), 3.61–3.65 (m, 2H, H-1b, H-2), 3.70–

3.74 (m, 4H, H-1’b, OMe), 3.84–4.01 (m, 2H, H₂-5), 4.04–4.10 (m,

2H, H₂propanoic acid), 4.20 (s, 4H, 2H₂ethylene), 4.34 (m, 1H,

H-3), 4.41 (m, 1H, H4), 4.53 (m, 1H, H-2’), 4.82 (d, J=3.6 Hz, 1H, H-

3’), 6.67–6.88 ppm (m, 7H, Harm); ¹³C NMR (100 MHz, CD₃CN): d=

36.7 (CH₂propanoic acid), 52.9 (C-2’), 56.4 (OMe), 57.9 (C-5), 59.2

(C-1’), 59.8 (C-1), 65.5 (2CH₂O), 65.6 (OCH₂propanoic acid), 70.0

(C-2), 71.5 (C-3), 72.1 (C-4), 73.4 (C-3’), 115.7, 116.3, 116.8, 118.1,

120.2 (CHarm), 134.3, 144.5, 144.6, 153.5, 155.3 (Cq Carm),

174.0 ppm (C=O); IR (thin film): n˜ =3277, 2925, 2856, 1675, 1508,

1436, 1286, 1229, 1201, 1181, 1127, 1067, 1020 cm^À1; LC–MS: t_R=

5.84 min (linear gradient 10!60% B); HRMS [QTOF, MH⁺] m/z cal-

culated for C₂₆H₃₅N₂O₉519.23371, found 519.23342.

H-3), 4.18–4.22 ppm (m, 1H, H-2); ¹³C NMR (150 MHz, MeOD): d=

51.9 (C-1), 60.9 (C-5), 69.8 (C-4), 76.1 (C-3), 77.4 ppm (C-2); IR (thin

film): n˜ =3416, 3372, 3277, 3022, 2968, 2959, 2941, 2887, 2833,

2762, 2745, 2488, 1576, 1449, 1396, 1375, 1360, 1298, 1260, 1215,

1167, 1109, 1074, 1038, 1003 cm^À1; HRMS [QTOF, MH⁺] m/z calcu-

lated for C₅H₁₁NO₃134.08117, found 134.08169.

Compound 75: Compound 74 was reacted with mesylate 6 ac-

cording to the general procedure described above. Yield 0.029 g

(79 mmol, 32%); R_f=0.80 (MeOH/EtOAc/NH₄OH 40:60:5, v/v/v).

½a²⁰=24.88 (c=0.58 in MeOH); H NMR (400 MHz, MeOD): d=2.52

1

D

(p, 1H, J=4.6 Hz, H-4), 2.69 (dd, J=5.6, 12.4 Hz, 1H, H-1’a), 2.72

(dd, J=5.2, 10.0 Hz, 1H, H-1a), 2.87 (d, J=9.9 Hz, 1H, H-1b), 3.01

(dd, J=8.4, 12.4 Hz, 1H, H-1’b), 3.65 (dd, J=4.7, 11.2 Hz, 1H, H-5a),

3.71 (dd, J=4.3, 11.3 Hz, 1H, H-5b), 3.75 (ddd, J=4.8, 5.6, 8.4 Hz,

1H, H-2’), 4.83 (dd, J=2.4, 3.6 Hz, 1H, H-3), 3.91 (dd, J=2.1, 4.6 Hz,

1H, H-2), 4.23 (s, 4H, 2H₂ethylene), 5.29 (d, J=5.0 Hz, 1H, H-3’),

6.83–6.89 ppm (m, 3H, Harm); ¹³C NMR (100 MHz, MeOD): d=60.8

(C-1’), 60.9 (C-2’), 61.1 (C-1), 63.3 (C-5), 65.6 (2CH₂O), 74.6 (C-4),

77.5 (C-2), 80.4 (C-3), 82.9 (C-3’), 115.9, 118.6, 119.9 (CHarm), 134.0,

145.2, 145.3 (Cq Carm), 161.5 ppm (C=O); IR (thin film): n˜ =3318,

2930, 2877, 1734, 1508, 1288, 1065, 1011 cm^À1; LC–MS: t_R=

5.77 min (linear gradient 0!60% B); ESI-MS: m/z=366.9 [M+H]⁺,

732.9 [2M+H]⁺; HRMS [QTOF, MH⁺] m/z calculated for C₁₇H₂₃N₂O₇

367.14998, found 367.15009.

2,3,5-Tri-O-benzyl-l-xylitol (72): 2,3,5-Tri-O-benzyl-l-xylofuranose

(71, 11.9 g, 28.3 mmol) was dissolved in EtOH (283 mL), cooled to

08C and NaBH₄(2.5 g, 65 mmol) was added. The reaction was

stirred for 5 h at room temperature after which the reaction mix-

ture was adjusted to pH 4–5 with AcOH and the mixture concen-

trated. The residue was taken up in EtOAc and washed with 1m

HCl (aq.), NaHCO₃(sat. aq.) and brine. The solution was dried over

anhydrous MgSO₄, filtered and concentrated under reduced pres-

sure. The residue was purified by flash chromatography (70%

EtOAc/n-pentane) yielding the title compound (11.0 g, 25.9 mmol,

92% yield). ½a²⁰=10.68 (c=100, CHCl₃). Analytical data was in full

D

agreement with its d-enantiomer 90.

Compound 76: The oxazolidine in compound 75 was hydrolyzed

1,4-Dideoxy-1,4-benzylimino-2,3,5-tri-O-benzyl-d-arabinitol (73):

2,3,5-Tri-O-benzyl-l-xylitol (72, 10.5 g, 24.9 mmol) was dissolved in

pyridine (52 mL), cooled to 08C and methanesulfonyl chloride

(9.7 mL, 124 mmol) was added. The reaction mixture was stirred at

this temperature after which the reaction was quenched with H₂O

and diluted with EtOAc. The suspension was washed with 1m HCl

(aq.), NaHCO₃(sat. aq.) and brine. The solution was dried over an-

hydrous MgSO₄and concentrated. The crude 1,4-di-O-methanesul-

fonyl-2,3,5-tri-O-benzyl-l-xylitol (14.4 g, 24.9 mmol) was dissolved

in benzylamine (81 mL, 750 mmol) and stirred at 558C overnight

after which the reaction mixture was allowed to cool to room tem-

perature and subsequently diluted with EtOAc. The mixture was

washed with 1m HCl (aq., 3x), NaHCO₃(sat. aq.) and brine before

being dried over anhydrous MgSO₄, filtered and concentrated

under reduced pressure. The residue was purified by flash chroma-

tography (10–15% Et₂O/n-pentane) yielding the title pyrrolidine

(10.5 g, 21 mmol, 84% yield over two steps); R_f=0.9 (acetone/tolu-

according to the saponification procedure described above. Yield

0.016 g (48 mmol, 60%); R_f=0.50(EtOH/Et₂O/NH₄OH 3:6:1, v/v/v).

1

½a²⁰=3.0 (c=0.33 in MeOH); H NMR (400 MHz, D₂O): d=2.45 (dd,

D

J=7.8, 13.2 Hz, 1H, H-1’a), 2.48 (q, 1H, J=4.8 Hz, H-4), 2.72 (dd, J=

5.9, 13.3 Hz, 1H, H-1’b), 2.83 (dd, J=5.6, 11.0 Hz, 1H, H-1a), 3.04

(dd, J=2.2, 11.0 Hz, 1H, H-1b), 3.22 (q, J=6.2 Hz, 1H, H-2’), 3.62

(dd, J=5.0, 7.2 Hz, 1H, H-5a), 3.65 (dd, J=5.0, 7.2 Hz, 1H, H-5b),

3.88 (dd, J=2.8, 4.7 Hz, 1H, H-3), 4.07 (dd, J=2.5, 5.3 Hz, 1H, H-2),

4.31 (s, 4H, 2H₂ethylene), 4.58 (d, J=6.4 Hz, 1H, H-3’), 6.89–

6.84 ppm (m, 3H, Harm); ¹³C NMR (100 MHz, D₂O): d=55.2 (C-2’),

56.8 (C-1’), 60.1 (C-1), 61.2 (C-5), 64.6 (2CH₂O), 72.4 (C-4), 74.0 (C-

3’), 75.7 (C-2), 79.0 (C-3), 115.5, 117.3, 120.0 (CHarm), 134.4, 142.8,

143.0 ppm (Cq Carm); IR (thin film): n˜ =3286, 2928, 1590, 1507,

1458, 1284, 1258, 1065 cm^À1; LC–MS: t_R=3.77 min (linear gradient

0!50% B); ESI-MS: m/z=341.0 [M+H]⁺, 681.3 [2M+H]⁺; HRMS

[QTOF, MH⁺] m/z calculated for C₁₆H₂₅N₂O₆341.17071, found

341.17070.

ene 1:9, v/v). ½a²⁰=À40.08 (c=1.00, CHCl₃); ¹H NMR (400 MHz,

D

Compound 26: Compound 76 was reacted with 10 according to

CDCl₃): d=2.56 (dd, J=10.7, 5.1 Hz, 1H, H-1a), 2.86 (q, J=5.3 Hz,

1H, H-4), 3.04 (d, J=10.7 Hz, 1H, H-1b), 3.49 (d, J=13.8 Hz, 1H,

CHH N-Bn), 3.60 (d, J=5.7 Hz, 2H, H-5), 3.86–3.93 (m, 2H, H-2, H-3),

4.14 (d, J=13.3 Hz, 1H, CHH N-Bn), 4.37 (d, J=12.2 Hz, 1H, CHH

Bn-2), 4.45 (d, J=12.2 Hz, 1H, CHH Bn-2), 4.50 (s, 2H, CH₂Bn-3),

4.52 (s, 2H, CH₂Bn-5), 7.19–7.37 ppm (m, 20H, CH_ArBn); ¹³C NMR

(100 MHz, CDCl₃): d=57.1 (C-1), 59.2 (CH₂N-Bn), 68.5 (C-4), 71.0

(CH₂Bn-2), 71.4 (C-5), 71.5 (CH₂Bn-3), 73.3 (CH₂Bn-5), 81.6 (C-2),

86.0 (C-3), 127.0–129.1 (CHarm Bn), 138.3, 138.3, 138.5, 138.9 ppm

(Cq Bn); IR (thin film): n˜ =3061, 3028, 2891, 2857, 2797, 1495, 1452,

1366, 1333, 1258, 1206, 1153, 1092, 1074, 1026 cm^À1; HRMS [QTOF,

MH⁺] m/z calculated for C₃₃H₃₅NO₃494.26897, found 494.26795.

the general condensation protocol described above. Yield 0.003 g

(4 mmol, 29%). ½a²⁰=15.9 (c=0.05 in MeOH); ¹H NMR (400 MHz,

D

MeOD): d=1.40–1.47 (m, 2H, H₂-4’’), 1.41–1.57 (m, 8H, H₂-3’’, H₂

adamantane), 1.67–1.78 (m, 6H, H₂adamantane), 1.95 (brs, 3H CH

adamantane), 2.18 (t, J=7.4 Hz, 2H, H₂-2’’), 2.96 (s, 2H, H₂adaman-

tane), 3.26 (dd, J=8.4, 13.6 Hz, 1H, H-1’a), 3.35 (t, J=6.2 Hz, 2H,

H₂-5’’), 3.43–4.46 (m, 1H, H-4), 3.49 (dd, J=3.6, 11.7 Hz, 1H, H-1a),

3.60 (d, J=11.7 Hz, 1H, H-1b), 3.93–3.99 (m, 4H, H-3, H₂-5, H-1’b),

4.16 (brs, 1H, H-2), 4.21 (brs, 4H, 2H₂ethylene), 4.58 (dt, J=3.2,

8.4 Hz, 1H, H-2’), 4.81 (d, J=3.5 Hz, 1H, H-3’), 6.77–6.89 ppm (m,

3H, Harm); ¹³C NMR (100 MHz, MeOD): d=23.4 (C-3’’), 29.8 (CH

adamantane), 30.2 (C-4’’), 36.7 (C-2’’), 38.3 (CH₂adamantane), 40.8

(CH₂adamantane), 52.9 (C-2’), 59.1 (C-1’), 60.7 (C-5), 61.0 (C-1), 65.6

(2CH₂O), 72.1 (C-5’’), 74.4 (C-3’), 75.9 (C-2), 77.5 (C-3), 79.8 (C-4),

83.1 (OCH₂adamantane), 116.4, 118.0, 120.2 ppm (CHarm); IR (thin

film): n˜ =3317, 1635, 1510, 1286, 1201, 1143, 1064, 1018 cm^À1; LC–

MS: t_R=7.34 min (linear gradient 10!90% B); ESI-MS: m/z=589.4

[M+H]⁺, 1177.3 [2M+H]⁺; HRMS [QTOF, MH⁺] m/z calculated for

C₃₂H₄₉N₂O₈589.34834, found 589.34826.

1,4-Dideoxy-1,4-imino-d-arabinitol hydrochloride (74): Com-

pound 73 (3.95 g, 8.0 mmol) was subjected to the general hydro-

genolysis procedure yielding the title compound (1.36 g, 8.0 mmol,

quant.). ½a²⁰=36.48 (c=1.00, MeOH); ¹H NMR (600 MHz, MeOD):

D

d=3.29 (d, J=12.0 Hz, 1H, H-1a), 3.47 (dd, J=12.0, 4.0 Hz, 1H, H-

1b), 3.52 (ddd, J=9.0, 4.5, 2.7 Hz, 1H, H-4), 3.80 (dd, J=11.6,

9.3 Hz, 1H, H-5a), 3.90 (dd, J=11.6, 4.7 Hz, 1H, H-5b), 3.98 (s, 1H,

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Compound 27: Compound 76 was reacted with 52 according to

in pyridine (50 mL), cooled to 08C and methanesulfonyl chloride

(9.2 mL, 118 mmol) was added. The mixture was stirred at this tem-

perature for 5 h. The reaction was quenched with H₂O and the mix-

ture taken up in EtOAc/1m HCl (aq.), washed with 1m HCl (aq.),

NaHCO₃(sat. aq.) and brine. The solution was dried over anhydrous

MgSO₄, filtered and concentrated. The crude 1,4-di-O-methanesul-

fonyl-2,3,5-tri-O-benzyl-l-arabinitol (13.7 g, 23.7 mmol) was dis-

solved in benzylamine (78 mL, 710 mmol) and stirred overnight at

558C. The reaction mixture was diluted with EtOAc and washed

with 1m HCl (aq.), Na₂CO₃(sat. aq.) and brine. The solution was

dried over anhydrous MgSO₄, filtered and concentrated under re-

duced pressure. The residue was purified by flash chromatography

(10–17.5% Et₂O/n-pentane) yielding the title pyrrolidine (10.7 g,

the general condensation protocol described above. Yield 0.005 g

(10 mmol, 64%). ½a²⁰=8.6 (c=0.09 in MeOH); ¹H NMR (400 MHz,

D

MeOD): 0.91 (t, J=6.9 Hz, 3H, CH₃), 1.20–1.35 (m, 10H, 5H₂nona-

noic amide), 1.44–1.50 (m, 2H, H₂nonanoic amide), 2.14 (t, J=

7.5 Hz, 2H, H₂-2’’), 3.26 (dd, J=8.4, 13.4 Hz, 1H, H-1’a), 3.43–4.45

(m, 1H, H-4), 3.48 (dd, J=3.5, 11.6 Hz, 1H, H-1a), 3.60 (d, J=

11.7 Hz, 1H, H-1b), 3.92–4.00 (m, 4H, H-3, H₂-5, H-1’b), 4.15 (brs,

1H, H-2), 4.21 (brs, 4H, 2H₂ethylene), 4.58 (dt, J=3.1, 8.2 Hz, 1H,

H-2’), 4.80 (d, J=3.1 Hz, 1H, H-3’), 6.77–6.92 ppm (m, 3H, Harm);

¹³C NMR (100 MHz, MeOD): d=14.3 (CH₃), 23.7, 26.7 30.3, 30.4,

30.5, 33.0, 37.0 (CH₂nonanoic amide), 52.9 (C-2’), 60.7 (C-1’), 60.9

(C-5), 61.1 (C-1), 65.6 (2CH₂O), 74.5 (C-3’), 75.9 (C-2), 77.5 (C-3),

79.9 (C-4), 116.4, 117.9, 120.2 (CHarm), 135.2, 144.8, 145.6 (Cq

Carm), 176.5 ppm (C=O); IR (thin film): n˜ =3282, 2927, 2856, 1672,

1508, 1434, 1288, 1201, 1137, 1068 cm^À1; LC–MS: t_R=6.44 min

(linear gradient 10!90% B); ESI-MS: m/z=481.3 [M+H]⁺, 960.9

[2M+H]⁺; HRMS [QTOF, MH⁺] m/z calculated for C₂₅H₄₁N₂O₇

481.29083, found 481.29057.

21.7 mmol, 92% yield over two steps); R_f=0.7 (Et₂O/n-pentane 2:3,

1

v/v). ½a²⁰=À35.58 (c=1.00, CHCl₃); H NMR (400 MHz, CDCl₃): d=

D

2.36 (dd, J=10.2, 5.5 Hz, 1H, H-1a), 3.18 (q, J=5.8 Hz, 1H, H-4),

3.31 (dd, J=10.2, 6.3 Hz, 1H, H-1b), 3.52 (d, J=13.3 Hz, 1H, CHH N-

Bn), 3.70 (dd, J=9.6, 5.2 Hz, 1H, H-5a), 3.90 (dd, J=9.6, 6.0 Hz, 1H,

H-5b), 4.04 (td, J=5.9, 3.0 Hz, 1H, H-2), 4.11 (dd, J=6.2, 2.9 Hz, 1H,

H-3), 4.16 (d, J=13.3 Hz, 1H, CHH N-Bn), 4.46 (s, 2H, H₂Bn-2), 4.55

(d, J=12.0 Hz, 1H, CHH Bn-5), 4.59 (d, J=12.0 Hz, 1H, CHH Bn-5),

4.61 (d, J=12.1 Hz, 1H, CHH Bn-3), 4.66 (d, J=12.1 Hz, 1H, CHH

Bn-3), 7.24–7.41 ppm (m, 20H, CHarm Bn); ¹³C NMR (100 MHz,

CDCl₃): d=57.3 (C-1), 59.5 (CH₂N-Bn), 65.4 (C-4), 69.6 (C-5), 71.5

(CH₂Bn-2), 72.2 (CH₂Bn-3), 73.6 (CH₂Bn-5), 82.2 (C-2), 83.6 (C-3),

127.0–129.1 (CHarm Bn), 138.3, 138.5, 138.6, 139.1 ppm (Cq Bn); IR

(thin film): n˜ =3061, 3028, 2911, 2859, 2799, 1495, 1452, 1364,

1344, 1308, 1246, 1206, 1088, 1072, 1026, 1003 cm^À1; HRMS [QTOF,

MH⁺] m/z calculated for C₃₃H₃₅NO₃494.26897, found 494.26807.

Compound 28: Compound 76 was reacted with 55 according to

the general condensation protocol described above. Yield 0.007 g

1

(13 mmol, 86%). ½a²⁰=13.0 (c=0.14 in MeOH); H NMR (400 MHz,

D

MeOD): d=2.47–2.68 (m, 2H, H₂-2’’), 3.25 (dd, J=8.7, 13.4 Hz, 1H,

H-1’a), 3.42–4.46 (m, 1H, H-4), 3.50 (dd, J=3.4, 11.9 Hz, 1H, H-1a),

3.60 (d, J=11.8 Hz, 1H, H-1b), 3.74 (m, 3H, OMe), 3.90–4.17 (m, 7H,

H-3, H₂-5, H-1’b, H-2, H₂propanoic acid), 4.19 (brs, 4H, 2H₂ethyl-

ene), 4.62 (dt, J=3.0, 8.6 Hz, 1H, H-2’), 4.80 (d, J=3.6 Hz, 1H, H-3’),

6.71–6.91 ppm (m, 7H, Harm); ¹³C NMR (100 MHz, MeOD): d=36.7

(CH₂propanoic acid), 53.1 (C-2’), 56.1 (OMe), 60.6 (C-1’), 61.0 (C-5),

61.1 (C-1), 65.6 (2CH₂O), 65.9 (OCH₂propanoic acid), 74.6 (C-3’),

76.0 (C-2), 77.4 (C-3), 80.2 (C-4), 115.7, 116.4, 116.6, 117.9, 120.4

(CHarm), 135.1, 144.7, 144.8, 154.0, 155.7 (Cq Carm), 173.8 ppm (C=

O); IR (thin film): n˜ =3257, 1639, 1508, 1288, 1201, 1143, 1066,

1016 cm^À1; LC–MS: t_R=5.04 min (linear gradient 10!90% B); ESI-

MS: m/z=519.2 [M+H]⁺, 1036.9 [2M+H]⁺; HRMS [QTOF, MH⁺]

m/z calculated for C₂₆H₃₅N₂O₉519.23371, found 519.23303.

1,4-Dideoxy-1,4-imino-d-xylitol hydrochloride (80): 1,4-Dideoxy-

1,4-benzylimino-2,3,5-tri-O-benzyl-d-xylitol (79, 3.95 g, 8.0 mmol)

was subjected to the general hydrogenolysis procedure yielding

the title compound (1.38 g, 8.0 mmol, quant.). ½a²⁰=13.38 (c=1,

D

1

MeOH); H NMR (600 MHz, MeOD): d=3.16 (d, J=12.3 Hz, 1H, H-

1a), 3.56 (dd, J=12.3, 4.1 Hz, 1H, H-1b), 3.80 (ddd, J=9.1, 4.5,

3.2 Hz, 1H, H-4), 3.87 (dd, J=11.7, 9.1 Hz, 1H, H-5a), 3.96 (dd, J=

11.7, 4.5 Hz, 1H, H-5b), 4.16 (dd, J=3.3, 1.5 Hz, 1H, H-3), 4.25 ppm

(dd, J=4.0, 1.5 Hz, 1H, H-2); ¹³C NMR (150 MHz, MeOD): d=52.0

(C-1), 59.0 (C-5), 65.1 (C-4), 75.8 (C-3), 76.1 ppm (C-2); IR (thin film):

n˜ =3341, 3026, 2955, 2805, 2714, 2650, 2540, 2469, 2399, 2351,

2295, 1578, 1454, 1402, 1385, 1366, 1294, 1281, 1246, 1204, 1098,

1082, 1055, 1034, 1016 cm^À1; HRMS [QTOF, MH⁺] m/z calculated

for C₅H₁₁NO₃134.08117, found 134.08186.

2,3,5-Tri-O-benzyl-l-arabinitol (78): To a cooled solution (08C) of

2,3,5-tri-O-benzyl-l-arabinofuranose (77, 20 g, 48 mmol) in EtOH

(500 mL) was added NaBH₄(4.2 g, 111 mmol). After stirring for 5 h

at room temperature, TLC analysis showed complete conversion of

the starting material into a lower running product. The reaction

mixture was adjusted to pH 4–5 by the addition of AcOH and the

resulting mixture was concentrated, taken up in EtOAc and

washed consecutively with 1m HCl (aq.), NaHCO₃(sat. aq.), and

brine. The organic layer was dried (anhydrous MgSO₄), filtered and

concentrated. The residue was purified by silica gel column chro-

matography (30–60% EtOAc/PE) yielding the title compound

(17.0 g, 41.0 mmol, 85% yield) as turbid syrup; R_f=0.6 (EtOAc/PE

Compound 81: Compound 80 was reacted with mesylate 6 ac-

cording to the general procedure described above. Yield 0.019 g

(52 mmol, 19%); R_f=0.65 (EtOAc/tBuOH/AcOH/H₂O, 1:1:1:1, v/v/v/

v). ½a²⁰=45.3 (c=0.38 in MeOH); ¹H NMR (400 MHz, MeOD): d=

1/1, v/v). ½a²⁰=À2.78 (c=1.00, CHCl₃); ¹H NMR (400 MHz, CDCl₃):

D

2.55 (dd, J=4.8, 10.1 Hz, 1H, H-1a), 2.72 (dd, J=5.6, 12.3 Hz, 1H,

H-1’a), 2.86 (q, 1H, J=5.3 Hz, H-4), 3.01 (dd, J=8.8, 12.4 Hz, 1H, H-

1’b), 3.20 (dd, J=5.6, 10.1 Hz, 1H, H-1b), 3.68 (dd, J=5.1, 11.2 Hz,

1H, H-5a), 3.71–3.78 (m, 1H, H-2’), 3.82 (dd, J=5.4, 11.2 Hz, 1H, H-

5b), 3.97 (t, J=5.2 Hz, 1H, H-3), 4.02 (dd, J=3.4, 5.8 Hz, 1H, H-2),

4.24 (s, 4H, 2H₂ethylene), 5.28 (d, J=5.4 Hz, 1H, H-3’), 6.79–

6.89 ppm (m, 3H, Harm); ¹³C NMR (100 MHz, MeOD): d=60.5 (C-1),

61.0 (C-2’), 61.2 (C-1’), 62.1 (C-5), 65.6 (2CH₂O), 68.6 (C-4), 77.6 (C-

3), 79.2 (C-2), 83.1 (C-3’), 115.9, 118.5, 119.9 (CHarm), 134.1, 145.2,

d=2.89 (bs, 1H, OH), 3.07 (bs, 1H, OH), 3.57–3.65 (m, 2H, C-5),

3.66–3.79 (m, 4H, C-1, C-2, C-3), 3.99 (q, J=5.1 Hz, 1H, C-4), 4.47

(d, J=11.8 Hz, 1H, CHH Bn), 4.50 (d, J=11.0 Hz, 1H, CHH Bn), 4.53

(d, J=11.1 Hz, 1H, CHH Bn), 4.57 (d, J=12.2 Hz, 2H, 2xCHH Bn),

4.61 (d, J=11.6 Hz, 1H, CHH Bn), 7.18–7.35 ppm (m, 15H, CHarm);

¹³C NMR (100 MHz, CDCl₃): d=61.3 (C-1), 70.5 (C-4), 71.1 (C-5), 72.8,

73.4, 73.7 (3CH₂Bn), 78.4 (C-3), 79.5 (C-2), 127.8–128.4 (CHarm

Bn), 137.9, 138.0 ppm (C_qBn); IR (thin film): n˜ =3482, 3447, 3372,

3310, 3030, 2868, 2338, 1715, 1454, 1396, 1352, 1321, 1209, 1092,

1072, 1028, 1003 cm^À1; HRMS: [M+H⁺] Calculated for C₂₆H₃₀O₅,

145.3 (Cq Carm), 161.4 ppm (C=O); IR (thin film): n=3355, 1735,

˜

1650, 1512, 1288, 1126, 1064 cm^À1; LC–MS: t_R=5.55 min (linear gra-

dient 0!50% B); ESI-MS: m/z=367.2 [M+H]⁺, 733.6 [2M+H]⁺;

HRMS [QTOF, MH⁺] m/z calculated for C₁₇H₂₃N₂O₇367.14998, found

367.15006.

423.21660, found 423.21658 cm^À1

.

1,4-Dideoxy-1,4-benzylimino-2,3,5-tri-O-benzyl-d-xylitol

(79):

2,3,5-Tri-O-benzyl-l-arabinitol (78, 10.0 g, 23.7 mmol) was dissolved

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Compound 82: The oxazolidine in compound 81 was hydrolyzed

according to the saponification procedure described above. The

obtained imine 82 was immediately condensed with the hydroxy-

succinimide esters 10, 42 and 55 as described in the general con-

densing procedure; LC–MS: t_R=3.55 min (linear gradient 0!50%

B); ESI-MS: m/z=341.2 [M+H]⁺.

NaHCO₃(sat. aq.), and brine. The organic layer was dried over an-

hydrous MgSO₄, filtered and concentrated under reduced pressure.

The residue was purified by flash chromatography (30–60% EtOAc/

n-pentane) yielding the title compound (24.6 g, 58.3 mmol, 97%

yield); R_f=0.45 (EtOAc/n-pentane 1:1, v/v). ½a²⁰=18.18 (c=1.00,

D

CHCl₃); ¹H NMR (400 MHz, CDCl₃): d=2.54 (s, 1H, OH-1), 2.91 (s,

1H, OH-4), 3.56 (dd, J=9.7, 5.9 Hz, 1H, H-5a), 3.60 (dd, J=9.8,

3.7 Hz, 1H, H-5b), 3.72–3.89 (m, 4H, H-1, H-2, H-3), 3.95–4.05 (m,

1H, H-4), 4.47 (d, J=11.9 Hz, 1H, CHH Bn), 4.51 (d, J=11.9 Hz, 1H,

CHH Bn), 4.58 (d, J=11.2 Hz, 1H, CHH Bn), 4.58 (d, J=11.7 Hz, 1H,

CHH Bn), 4.63 (d, J=11.6 Hz, 1H, CHH Bn), 4.72 (d, J=11.2 Hz, 1H,

CHH Bn), 7.13–7.47 ppm (m, 15H, CHarm Bn); ¹³C NMR (100 MHz,

CDCl₃): d=61.1 (C-1), 70.7 (C-4), 71.1 (C-5), 72.1, 73.5, 74.1 (3xCH₂

Bn), 79.4, 79.5 (C-2, C-3), 127.9–128.6 (CHarm Bn), 137.9, 138.1,

138.1 ppm (C_qBn); IR (thin film): n˜ =3348, 3063, 3030, 2866, 1719,

1497, 1452, 1395, 1360, 1329, 1314, 1273, 1207, 1088, 1067,

Compound 29: Compound 82 was reacted with 10 according to

the general condensation protocol described above. Yield 0.003 g

(5 mmol, 28%). (thin film): n˜ =2931, 2856, 1700, 1684, 1653, 1509,

1423, 1205, 1183, 1136, 1017 cm^À1; LC–MS: t_R=9.95 min (linear gra-

dient 10!60% B); ESI-MS: m/z=589.3 [M+H]⁺, 1176.9 [2M+H]⁺,

1201.5 [2M+H]⁺; HRMS [QTOF, MH⁺] m/z calculated for

C₃₂H₄₉N₂O₈589.34834, found 589.34810.

Compound 30: Compound 82 was reacted with 52 according to

the general condensation protocol described above. Yield 0.002 g

(4 mmol, 26%); IR (thin film): n˜ =2929, 2856, 1684, 1653, 1509,

1206, 1131, 1022 cm^À1; LC–MS: t_R=8.40 min (linear gradient 10!

60% B); ESI-MS: m/z=481.2 [M+H]⁺, 961.0 [2M+H]⁺, 983.1

[2M+Na]⁺; HRMS [QTOF, MH⁺] m/z calculated for C₂₅H₄₁N₂O₇

481.29083, found 481.29053.

1026 cm^À1

;

HRMS [QTOF, MH⁺] m/z calculated for C₂₆H₃₀O₅

423.21660, found 423.21622 (Scheme 5).

1,4-Dideoxy-1,4-benzylimino-2,3,5-tri-O-benzyl-d-ribitol

(85):

2,3,5-Tri-O-benzyl-d-ribitol (84, 7.60 g, 18.0 mmol), triphenylphos-

phine (10.9 g, 41 mmol) and imidazole (3.7 g, 54 mmol) were co-

evaporated thrice with dry toluene before being dissolved in

CH₂Cl₂(180 mL) and cooled to À308C. Iodine (11 g, 43 mmol) was

slowly added and the reaction mixture stirred for 2 days at À308C,

then 1 day at À208C. The solution was concentrated under re-

duced pressure, dry toluene (180 mL) added and the mixture held

at reflux for 2 h. The reaction mixture was diluted with Et₂O,

washed with Na₂S₂O₃(sat. aq.) and brine, dried over anhydrous

MgSO₄, filtered and concentrated under reduced pressure. The resi-

due was co-evaporated with Et₂O to get rid of the residual toluene

and then dissolved in Et₂O after which it was filtered to remove

most of the Ph₃PO. The crude 1,4-dideoxy-1,4-diiodo-2,3,5-tri-O-

benzyl-l-lyxitol (18 mmol) was dissolved in benzylamine (59 mL,

540 mmol) and stirred for 2 days at 558C. The mixture was diluted

Compound 31: Compound 82 was reacted with 55 according to

the general condensation protocol described above. Yield 0.002 g

(3 mmol, 20%); IR (thin film): n˜ =3360, 2625, 2857, 1684, 1506,

1205, 1180, 1134, 1131, 1027 cm^À1; LC–MS: t_R=6.01 min (linear gra-

dient 10!60% B); ESI-MS: m/z=519.1 [M+H]⁺, 1037.3 [2M+H]⁺,

1058.9 [2M+Na]⁺; HRMS [QTOF, MH⁺] m/z calculated for

C₂₆H₃₅N₂O₉519.23371, found 519.23339.

2,3,5-Tri-O-benzyl-d-ribitol (84): 2,3,5-Tri-O-benzyl-d-ribofuranose

(83, 25.4 g, 60.4 mmol) was dissolved in EtOH (600 mL) and cooled

to 08C. NaBH₄(5.25 g, 139 mmol) was added and the reaction

stirred at room temperature for 3 h. The reaction mixture was ad-

justed to pH 4–5 with AcOH and the mixture concentrated. The

residue was taken up in EtOAc and washed with 1m HCl (aq.),

Scheme 5. Reagents and conditions: a) NaBH₄, EtOH; b) 1) PH₃P, I₂, imidazole, DMF, À358C, 2) PhNH₂, 558C; c) H₂, Pd/C, HCl, EtOH; d) 6, K₂CO₃, DMF, 808C;

e) LiOH, dioxane/H₂O, microwave, 1658C; f) 10, 52 or 55, DiPEA, DMF; g) LiAlH₄, THF, 08C; h) 1) MsCl, pyridine, 08C, 2) PhNH₂, 558C.

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with EtOAc, washed with 1m HCl (aq.), NaHCO₃(sat. aq.) and brine,

dried over anhydrous MgSO₄, filtered and concentrated under re-

duced pressure. The residue was purified by flash chromatography

(15–22.5% Et₂O/n-pentane) yielding the title compound (6.10 g,

12.4 mmol, 69% yield over two steps); R_f=0.55 (Et₂O/n-pentane

H₂-4’’), 1.45–1.53 (m, 8H, H₂-3’’, H₂adamantane), 1.64–1.76 (m, 6H,

H₂adamantane), 1.97 (s, 3H CH adamantane), 2.21 (t, J=7.3 Hz,

2H, H₂-2’’), 2.91 (s, 2H, H₂adamantane), 3.29 (t, J=6.2 Hz, 2H, H₂-

5’’), 3.31–3.40 (m, 3H, H-1a, H-1’a, H-4), 3.65 (dd, J=9.5, 13.2 Hz,

1H, H-1’b), 3.80 (dd, J=7.9, 12.7 Hz, H-5a), 3.88–3.97 (m, 3H, H-1b,

H-3, H-5b), 4.19–4.27 (m, 6H, H-2, H-2’, 2H₂ethylene), 4.81 (d, J=

3.9 Hz, 1H, H-3’), 6.84–6.97 ppm (m, 3H, Harm); ¹³C NMR (100 MHz,

CD₃CN): d=23.3 (C-3’’), 29.4 (CH adamantane), 29.6 (C-4’’), 37.8 (Cq

adamantane), 36.1 (C-2’’), 38.0 (CH₂adamantane), 40.5 (CH₂ada-

mantane), 54.2 (C-2’), 59.8 (C-5), 61.3 (C-1), 62.3 (C-1’), 65.4 (2

CH₂O), 71.8 (C-5’’), 72.7 (C-3’), 75.3 (C-2), 77.2 (C-3), 77.9 (C-4), 82.6

(OCH₂adamantane), 116.1, 118.1, 119.9 (CHarm), 134.8, 144.5,

144.7 ppm (Cq Carm); IR (thin film): n˜ =3311, 2905, 2850, 1675,

1542, 1506, 1448, 1287, 1203, 1180, 1136, 1068, 1018 cm^À1; LC–MS:

t_R=9.83 min (linear gradient 10!60% B); ESI-MS: m/z=589.3 [M+

H]⁺, 1177.1 [2M+H]⁺; HRMS [QTOF, MH⁺] m/z calculated for

C₃₂H₄₉N₂O₈589.34834, found 589.34818.

2:3, v/v). ½a²⁰=À32.98 (c=1.00, CHCl₃); H NMR (400 MHz, CDCl₃):

1

D

d=2.68 (dd, J=8.8, 8.3 Hz, 1H, H-1a), 3.05 (dt, J=6.1, 4.3 Hz, 1H,

H-4), 3.11 (dd, J=9.0, 5.7 Hz, 1H, H-1b), 3.32 (dd, J=9.9, 6.2 Hz,

1H, H-5a), 3.39 (dd, J=9.9, 4.6 Hz, 1H, H-5b), 3.58 (d, J=13.0 Hz,

1H, CHH N-Bn), 3.85 (dd, J=5.1, 3.6 Hz, 1H, H-3), 3.90 (dt, J=7.9,

5.5 Hz, 1H, H-2), 3.99 (d, J=12.9 Hz, 1H, CHH N-Bn), 4.42–4.52 (m,

4H, 2xCHH Bn-2, 2xCHH Bn-5), 4.59 (d, J=12.2 Hz, 1H, CHH Bn-3),

4.64 (d, J=12.2 Hz, 1H, CHH-Bn-3), 7.20–7.35 ppm (m, 20H, CHarm

Bn); ¹³C NMR (1001 MHz, CDCl₃): d=55.9 (C-1), 60.2 (CH₂N-Bn),

68.2 (C-4), 71.1 (C-5), 71.4 (CH₂Bn-3), 71.6, 73.4 (CH₂Bn-2, CH₂Bn-

5), 76.5 (C-2), 79.0 (C-3), 127.1–129.0 (CHarm Bn), 138.4, 138.4,

138.6, 139.2 ppm (Cq Bn); IR (thin film): n˜ =3061, 3028, 2857, 2799,

1495, 1452, 1364, 1321, 1310, 1258, 1207, 1092, 1072, 1051,

1026 cm^À1HRMS [QTOF, MH⁺] m/z calculated for C₃₃H₃₅NO₃

;

494.26897, found: 494.26796.

Compound 33: Compound 88 was reacted with 52 according to

the general condensation protocol described above. Yield 0.014 g

(28 mmol, 37%); ¹H NMR (400 MHz, CD₃CN): d=0.89 (t, J=6.9 Hz,

3H, CH₃), 1.12–1.44 (m, 12H, 6H₂nonanoic amide), 2.16 (t, J=

7.3 Hz, 2H, H₂-2’’), 3.31–3.43 (m, 3H, H-1a, H-1’a, H-4), 3.68 (dd, J=

9.5, 13.2 Hz, 1H, H-1’b), 3.80 (dd, J=7.7, 12.1 Hz, 1H, H-5a), 3.85–

3.93 (m, 3H, H-1b, H-3, H-5b), 4.19–4.15 (m, 6H, H-2, H-2’, 2H₂

ethylene), 4.81 (d, J=3.9 Hz, 1H, H-3’), 6.81–6.90 ppm (m, 3H,

Harm); ¹³C NMR (100 MHz, CD₃CN): d=14.4 (CH₃), 23.4, 26.4 29.7,

29.9, 30.0, 32.6, 36.5 (CH₂nonanoic amide), 54.0 (C-2’), 59.7 (C-5),

61.3 (C-1), 62.1 (C-1’), 65.4 (2CH₂O), 72.7 (C-3’), 75.3 (C-2), 77.3 (C-

3), 77.9 (C-4), 116.0, 118.0, 119.9 (CHarm), 134.8, 144.5, 144.6 ppm

(Cq Carm); IR (thin film): n˜ =3313, 2927, 2856, 1668, 1662, 1287,

1203, 1181, 1134, 1068, 1017 cm^À1; LC–MS: t_R=8.29 min (linear gra-

dient 10!60% B); ESI-MS: m/z=481.2 [M+H]⁺, 960.8 [2M+H]⁺;

HRMS [QTOF, MH⁺] m/z calculated for C₂₅H₄₁N₂O₇481.29083, found

481.29058.

1,4-Dideoxy-1,4-imino-d-ribitol hydrochloride (86): 1,4-Dideoxy-

1,4-benzylimino-2,3,5-tri-O-benzyl-d-ribitol (85, 3.95 g, 8.0 mmol)

was subjected to the general hydrogenolysis procedure yielding

the title compound (1.35 g, 7.9 mmol, 99%). ½a²⁰=51.68 (c=1.00,

D

MeOH); ¹H NMR (600 MHz, MeOD): d=3.26 (dd, J=12.5, 2.0 Hz,

1H, H-1a), 3.39 (dd, J=12.4, 4.0 Hz, 1H, H-1b), 3.54 (ddd, J=8.8,

5.9, 3.3 Hz, 1H, H-4), 3.78 (dd, J=12.0, 5.9 Hz, 1H, H-5a), 3.91 (dd,

J=12.0, 3.3 Hz, 1H, H-5b), 4.13 (dd, J=8.3, 4.0 Hz, 1H, H-3),

4.26 ppm (td, J=4.0, 1.9 Hz, 1H, H-2); ¹³C NMR (150 MHz, MeOD):

d=51.1 (C-1), 59.4 (C-5), 63.9 (C-4), 71.1 (C-2), 72.9 ppm (C-3); IR

(thin film): n˜ =3383, 3345, 3289, 3256, 2938, 2895, 2849, 2747,

2716, 2695, 2596, 2538, 2475, 1449, 1418, 1385, 1323, 1233, 1192,

1132, 1098, 1051, 1034, 1003 cm^À1; HRMS [QTOF, MH⁺] m/z calcu-

lated for C₅H₁₁NO₃134.08117, found 134.08173.

Compound 34: Compound 88 was reacted with 55 according to

the general condensation protocol described above. Yield 0.008 g

(15 mmol, 19%); ¹H NMR (400 MHz, CD₃CN): d=2.64 (brs, 2H, H₂-

2’’), 3.40 (brs, 3H, H-1a, H-1’a, H-4), 3.67–4.30 (brm, 16H, H-1’b, H-

2’, H-1b, H-2, H-3, H₂-5, H₂propanoic acid, 2H₂ethylene, OMe),

4.83 (brs, 1H, H-3’), 6.86 ppm (brs, 7H, Harm); ¹³C NMR (100 MHz,

CD₃CN): d=36.6 (CH₂propanoic acid), 54.1 (C-2’), 56.3 (OMe), 59.9

(C-5), 61.4 (C-1), 62.3 (C-1’), 65.4 (2CH₂O), 65.5 (OCH₂propanoic

acid), 72.7 (C-3’), 75.3 (C-2), 77.1 (C-3), 80.0 (C-4), 115.6, 116.0, 119.0

(CHarm), 134.7, 144.4, 153.4 ppm (Cq Carm); IR (thin film): n˜ =3307,

2927, 2856, 1684, 1508, 1287, 1203, 1131, 1068, 1029 cm^À1; LC–MS:

t_R=5.99 min (linear gradient 10!60% B); ESI-MS: m/z=519.1 [M+

H]⁺, 1036.6 [2M+H]⁺; HRMS [QTOF, MH⁺] m/z calculated for

C₂₆H₃₅N₂O₉519.23371, found 519.23337.

Compound 87: Compound 86 was reacted with mesylate 6 ac-

cording to the general procedure described above. Yield 0.084 g

(230 mmol, 58%) R_f=0.65 (EtOAc/tBuOH/AcOH/H₂O, 1:1:1:1, v/v/v/

v). ½a²⁰=30.7 (c=1.05 in MeOH); ¹H NMR (400 MHz, MeOD): d=

D

2.42 (dd, J=6.6, 9.3 Hz, 1H, H-1a), 2.66 (q, 1H, J=4.7 Hz, H-4), 2.76

(dd, J=5.6, 12.3 Hz, 1H, H-1’a), 2.99 (dd, J=6.0, 9.6 Hz, 1H, H-1b),

3.00 (dd, J=8.4, 12.4 Hz, 1H, H-1’b), 3.58 (dd, J=4.8, 11.3 Hz, 1H,

H-5a), 3.63 (dd, J=4.8, 11.4 Hz, 1H, H-5b), 3.74 (dt, J=5.5, 8.4 Hz,

1H, H-2’), 3.82 (t, J=4.8 Hz, 1H, H-3), 3.97 (q, J=5.8 Hz, 1H, H-2),

4.23 (s, 4H, 2x H₂ethylene), 5.26 (d, J=5.5 Hz, 1H, H-3’), 6.84–

6.87 ppm (m, 3H, Harm); ¹³C NMR (100 MHz, MeOD): d=59.3 (C-1),

60.7 (C-2’), 61.3 (C-1’), 63.6 (C-5), 65.6 (2CH₂O), 71.5 (C-2), 72.4 (C-

4), 74.1 (C-3), 83.2 (C-3’), 116.0, 118.5, 120.0 (CHarm), 133.9, 145.1,

145.3 (Cq Carm), 161.4 ppm (C=O); IR (thin film): n˜ =3363, 2939,

2885, 1728, 1643, 1512, 1427, 1288, 1064, 1018 cm^À1; LC–MS: t_R=

4.91 min (linear gradient 0!50% B); ESI-MS: m/z=367.1 [M+H]⁺,

733.5 [2M+H]⁺; HRMS [QTOF, MH⁺] m/z calculated for C₁₇H₂₃N₂O₇

367.14998, found 367.15001.

2,3,5-Tri-O-benzyl-D-xylitol (90): 2,3,5-Tri-O-benzyl-d-xylofuranose

(17, 23 g, 54 mmol) was dissolved in EtOH (550 mL), put under an

argon atmosphere and cooled to 08C. NaBH₄(4.7 g, 123 mmol)

was added and the reaction stirred at room temperature for 4 h.

The reaction was adjusted to pH 4–5 by addition of AcOH and the

resulting mixture was concentrated. The residue was taken up in

EtOAc and washed with 1m HCl (aq.), NaHCO₃(sat. aq.) and brine.

The solution was dried over anhydrous MgSO₄, filtered and con-

centrated under reduced pressure. The product was purified by

flash chromatography (25–60% EtOAc/n-pentane) yielding the title

compound (22 g, 52 mmol, 97% yield); R_f=0.65 (50/50 EtOAc/n-

Compound 88: The oxazolidine in compound 87 was hydrolyzed

according to the saponification procedure described above. The

obtained imine 88 was immediately condensed with the hydroxy-

succinimide esters 10, 42 and 55 as described in the general con-

densing procedure; LC–MS: t_R=3.70 min (linear gradient 0!50%

B); ESI-MS: m/z=341.2 [M+H]⁺, 681.6 [2M+H]⁺.

1

Compound 32: Compound 88 was reacted with 10 according to

the general condensation protocol described above. Yield 0.010 g

(16 mmol, 21%); ¹H NMR (400 MHz, CD₃CN): d=1.31–1.38 (m, 2H,

pentane); H NMR (400 MHz, CDCl₃): d=2.86 (s, 1H, OH-1), 3.02 (s,

1H, OH-4), 3.41 (dd, J=9.4, 6.2 Hz, 1H, C-5b), 3.50 (dd, J=9.4,

6.4 Hz, 1H, C-5a), 3.73–3.63 (m, 2H, C-2, C-3), 3.81–3.73 (m, 2H, C-

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1), 4.07–4.01 (m, 1H, C-4), 4.42 (d, J=11.9 Hz, 1H, CHH Bn-5), 4.51–

4.46 (m, 2H, CHH Bn-3, CHH Bn-5), 4.57 (d, J=11.8 Hz, 1H, CHH

Bn-2), 4.61 (d, J=11.9 Hz, 1H, CHH Bn-2), 4.65 (d, J=11.4 Hz, 1H,

CHH Bn-3), 7.24–7.21 (m, 2H, CHAr Bn), 7.36–7.24 ppm (m, 13H,

CHAr Bn), ¹³C NMR (101 MHz, CDCl₃): d=138.1, 138.0, 137.9 (Cq

Bn), 128.5, 128.5, 128.5, 128.4, 128.0, 128.0, 127.9, 127.8 (CHAr Bn),

78.7 (C-2), 77.3 (C-3), 74.2 (CH2 Bn-3), 73.3 (CH2 Bn-5), 72.4 (CH2

Compound 35: Compound 94 was reacted with 10 according to

the general condensation protocol described above. Yield 0.014 g

(23 mmol, 44%); ¹H NMR (400 MHz, CD₃CN): d=1.33–1.40 (m, 2H,

H₂-4’’), 1.45–1.53 (m, 8H, H₂-3’’, H₂adamantane), 1.64–1.76 (m, 6H,

H₂adamantane), 1.96 (s, 3H CH adamantane), 2.15 (t, J=7.3 Hz,

2H, H₂-2’’), 2.93 (s, 2H, H₂adamantane), 3.30 (t, J=6.2 Hz, 2H, H₂-

5’’), 3.31–3.38 (m, 2H, H-1a, H-1’a,), 3.49 (brs, 1H, H-4), 3.73–3.79

(m, 3H, H-1’b, H-1b, H-5a), 3.95 (dd, J=3.3, 12.7 Hz, 1H, H-5b), 4.13

(brs, 1H, H-3), 4.22 (s, 4H, 2H₂ethylene), 4.25 (brs, 1H, H-2), 4.35

(brs, 1H, H-2’), 4.78 (d, J=3.7 Hz, 1H, H-3’), 6.81–6.90 ppm (m, 3H,

Harm); ¹³C NMR (100 MHz, CD₃CN): d=23.1 (C-3’’), 29.3 (CH ada-

mantane), 29.7 (C-4’’), 34.9 (Cq adamantane), 36.3 (C-2’’), 38.0 (CH₂

adamantane), 40.5 (CH₂adamantane), 52.9 (C-2’), 58.1 (C-5), 61.1

(C-1), 62.6 (C-1’), 65.4 (2CH₂O), 70.4 (C-2), 71.8 (C-5’’), 72.6 (C-3),

72.8 (C-3’), 73.7 (C-4), 82.6 (OCH₂adamantane), 116.1, 117.9, 120.0

(CHarm), 134.7, 144.4, 144.5 ppm (Cq Carm); IR (thin film): n˜ =3308,

Bn-2), 71.3 (C-5), 68.6 (C-4), 60.6 ppm (C-1). ½a²⁰=À9.78 (c=1,

D

CHCl₃); IR (thin film): n˜ =694, 716, 733, 822, 881, 903, 918, 980,

1018, 1024, 1057, 1084, 1096, 1206, 1248, 1279, 1294, 1366, 1385,

1400, 1452, 1497, 1578, 1726, 2471, 2542, 2716, 2866, 3028,

3343 cm^À1

;

HRMS [QTOF, MH⁺] m/z calculated for C₂₆H₃₀O

423.21660, found 423.21633.

1,4-Dideoxy-1,4-benzylimino-2,3,5-tri-O-benzyl-l-arabinitol (91):

2,3,5-Tri-O-benzyl-d-xylitol (90, 10.0 g, 23.7 mmol) was dissolved in

pyridine (50 mL), cooled to 08C and methanesulfonyl chloride

(9.2 mL, 118 mmol) was added. The mixture was stirred at this tem-

perature for 4 h. The reaction was quenched with H₂O and the mix-

ture taken up in EtOAc/1m HCl (aq.), washed with 1m HCl (aq.),

NaHCO₃(sat. aq.) and brine. The solution was dried over anhydrous

MgSO₄, filtered and concentrated under reduced pressure. The

crude 1,4-di-O-methanesulfonyl-2,3,5-tri-O-benzyl-d-xylitol (12.5 g,

21.6 mmol) was dissolved in benzylamine (71 mL, 650 mmol) and

stirred overnight at 558C. The reaction mixture was diluted with

EtOAc and washed with 1m HCl (aq.), NaHCO₃(sat. aq.) and brine.

The solution was dried over anhydrous MgSO₄, filtered and con-

centrated under reduced pressure. The residue was purified by

flash chromatography (10–15% Et₂O/n-pentane) yielding title com-

pound (7.60 g, 15.4 mmol, 71% yield over two steps). Analytical

2904, 2849, 1675, 1506, 1287, 1257, 1202, 1180, 1128, 1068 cm^À1

;

LC–MS: t_R=9.80 min (linear gradient 10!60% B); ESI-MS: m/z=

589.3 [M+H]⁺, 1176.9 [2M+H]⁺; HRMS [QTOF, MH⁺] m/z calculat-

ed for C₃₂H₄₉N₂O₈589.34834, found 589.34819.

Compound 36: Compound 94 was reacted with 52 according to

the general condensation protocol described above. Yield 0.009 g

1

(19 mmol, 37%); H NMR (400 MHz, CD₃CN): d=0.89 (brs, 3H, CH₃),

1.25–1.58 (m, 12H, 6H₂nonanoic amide), 2.15 (brs, 2H, H₂-2’’),

3.29–3.39 (m, 2H, H-1a, H-1’a), 3.50 (brs, 1H, H-4), 3.71–3.81 (m,

3H, H-1’b, H-1b, H-5a), 3.95 (brs, 1H, H-5b), 4.13 (brs, 1H, H-3),

4.22 (s, 4H, 2H₂ethylene), 4.25 (brs, 1H, H-2), 4.35 (brs, 1H, H-

2’), 4.79 (brs, 1H, H-3’), 6.81–6.86 ppm (m, 3H, Harm); ¹³C NMR

(100 MHz, CD₃CN): d=14.4 (CH₃), 23.4, 26.3 29.8, 29.9, 30.0, 32.6,

36.6 (CH₂nonanoic amide), 53.0 (C-2’), 57.9 (C-5), 61.3 (C-1), 62.6

(C-1’), 65.4 (2CH₂O), 70.4 (C-2), 72.6 (C-3), 72.9 (C-3’), 73.7 (C-4),

116.1, 118.0, 120.0 (CHarm), 134.4, 144.4, 144.5 ppm (Cq Carm); IR

(thin film): n˜ =3305, 2929, 2856, 1684, 1522, 1287, 1203, 1182,

1134, 1068 cm^À1; LC–MS: t_R=8.42 min (linear gradient 10!60% B);

ESI-MS: m/z=481.2 [M+H]⁺, 983.3 [2M+Na]⁺; HRMS [QTOF, MH⁺

] m/z calculated for C₂₅H₄₁N₂O₇481.29083, found 481.29059.

data were in full accordance with its d-enantiomer 67. ½a²⁰=38.08

D

(c=1.00, CHCl₃).

1,4-Dideoxy-1,4-imino-l-arabinitol hydrochloride (92): 1,4-Di-

deoxy-1,4-benzylimino-2,3,5-tri-O-benzyl-l-arabinitol

(3.70 g,

7.50 mmol) was subjected to general hydrogenolysis procedure

yielding title compound (1.30 g, 7.50 mmol, quant.). Analytical data

were in full accordance with its d-enantiomer 74. ½a²⁰=À38.98

D

Compound 37: Compound 94 was reacted with 55 according to

the general condensation protocol described above. Yield 0.010 g

(19 mmol, 38%); ¹H NMR (400 MHz, CD₃CN): d=2.59 (brs, 2H, H₂-

2’’), 3.33–3.39 (m, 2H, H-1a, H-1’a), 3.50 (brs, 1H, H-4), 3.70–3.84

(m, 6H, H-1’b, H-1b, H-5a, OMe), 3.91–4.12 (m, 4H, H-3, H-5b, H₂

propanoic acid), 4.20 (s, 4H, 2H₂ethylene), 4.25 (brs, 1H, H-2),

4.40 (brs, 1H, H-2’), 4.79 (brs, 1H, H-3’), 6.73–6.97 ppm (m, 7H,

Harm); ¹³C NMR (100 MHz, CD₃CN): d=36.8 (CH₂propanoic acid),

53.0 (C-2’), 56.3 (OMe), 59.9 (C-5), 61.4 (C-1), 62.4 (C-1’), 65.4 (2

CH₂O), 65.5 (OCH₂propanoic acid), 70.4 (C-2), 72.5 (C-3), 72.9 (C-3’),

73.6 (C-4), 115.7, 116.2, 116.7, 118.0, 120.1 (CHarm), 134.3, 144.5,

144.6, 153.5, 155.3 ppm (Cq Carm); IR (thin film): n˜ =3305, 2929,

2854, 1668, 1506, 1287, 1230, 1201, 1134, 1067, 1042 cm^À1; LC–MS:

t_R=5.90 min (linear gradient 10!60% B); ESI-MS: m/z=519.1 [M+

H]⁺, 1036.6 [2M+H]⁺; HRMS [QTOF, MH⁺] m/z calculated for

C₂₆H₃₅N₂O₉519.23371, found 519.23346.

(c=1.00, MeOH).

Compound 93: Compound 92 was reacted with mesylate 6 ac-

cording to the general procedure described above. Yield 0.057 g

(156 mmol, 39%); R_f=0.65 (EtOAc/tBuOH/AcOH/H₂O, 1:1:1:1, v/v/v/

v). ½a²⁰=80.2 (c=0.38 in MeOH); ¹H NMR (400 MHz, MeOD): d=

D

2.47 (q, 1H, J=4.2 Hz, H-4), 2.57 (dd, J=3.8, 12.6 Hz, 1H, H-1’a),

2.58 (dd, J=5.6, 9.6 Hz, 1H, H-1a), 3.00 (dd, J=9.6, 12.4 Hz, 1H, H-

1’b), 3.01 (dd, J=8.8, 9.2 Hz, 1H, H-1b), 3.64 (dd, J=4.1, 11.4 Hz,

1H, H-5a), 3.69 (dd, J=4.6, 11.4 Hz, 1H, H-5b), 3.82 (ddd, J=3.1,

6.7, 9.5 Hz, 1H, H-2’), 3.90–3.94 (m, 2H, H-2, H-3), 4.24 (s, 4H, 2H₂

ethylene), 5.12 (d, J=6.6 Hz, 1H, H-3’), 6.83–6.90 ppm (m, 3H,

Harm); ¹³C NMR (100 MHz, MeOD): d=59.5 (C-1’), 60.4 (C-1), 61.0

(C-2’), 62.4 (C-5), 65.6 (2CH₂O), 74.5 (C-4), 77.4 (C-2), 80.2 (C-3),

82.5 (C-3’), 116.2, 118.6, 120.1 (CHarm), 132.9, 145.3, 145.7 (Cq

Carm), 161.2 ppm (C=O); IR (thin film): n˜ =3317, 2939, 2831, 1743,

1651, 1512, 1450, 1288, 1110, 1018 cm^À1; LC–MS: t_R=4.99 min

(linear gradient 0!50% B); ESI-MS: m/z=366.9 [M+H]⁺, 733.6

[2M+H]⁺; HRMS [QTOF, MH⁺] m/z calculated for C₁₇H₂₃N₂O₇

367.14998, found 367.15004.

1,4-Dideoxy-1,4-benzylimino-2,3,5-tri-O-benzyl-l-lyxitol

(95):

2,3,5-Tri-O-benzyl-d-ribitol (84, 6.30 g, 15.0 mmol) was dissolved in

pyridine (32 mL), cooled to 08C and methanesulfonyl chloride

(5.8 mL, 75 mmol) was added. The reaction mixture was stirred at

this temperature for 2.5 h after which the reaction was quenched

with H₂O and diluted with EtOAc. The suspension was washed

with 1m HCl (aq.), NaHCO₃(sat. aq.) and brine. The solution was

dried over anhydrous MgSO₄and concentrated. The crude 1,4-di-

O-methanesulfonyl-2,3,5-tri-O-benzyl-d-ribitol (8.5 g, 14.7 mmol)

was dissolved in benzylamine (49 mL, 450 mmol) and stirred at

Compound 94: The oxazolidine in compound 93 was hydrolyzed

according to the saponification procedure described above. The

obtained imine 94 was immediately condensed with the hydroxy-

succinimide esters 10, 42 and 55 as described in the general con-

densing procedure; LC–MS: t_R=3.29 min (linear gradient 0!50%

B); ESI-MS: m/z=341.2 [M+H]⁺, 681.5 [2M+H]⁺.

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558C for 2 days after which the reaction mixture was allowed to

cool to room temperature and subsequently diluted with EtOAc.

The mixture was washed with 1m HCl (aq.), Na₂CO₃(sat. aq.) and

brine before being dried over anhydrous MgSO₄, filtered and con-

centrated under reduced pressure. The residue was purified by

flash chromatography (12.5–20% Et₂O/n-pentane) yielding the title

3H, CH₃), 1.09–1.57 (m, 12H, 6H₂nonanoic amide), 2.17 (m, 2H,

H₂-2’’), 3.22 (dd, J=5.1, 12.1 Hz, 1H, H-1a), 3.33 (dd, J=2.2, 13.7 Hz,

1H, H-1’a), 3.59 (m, 1H, H-2), 3.66 (dd, J=9.5, 13.4 Hz, 1H, H-1’b),

3.78 (dd, J=3.4, 12.1 Hz, 1H, H-1b), 3.88 (dd, J=4.2, 12.9 Hz, 1H,

H-5a), 3.95 (dd, J=5.4, 12.7 Hz, 1H, H-5b), 4.21 (s, 4H, 2H₂ethyl-

ene), 4.27 (ddd, J=2.2, 3.9, 8.8 Hz, 1H, H-2’), 4.37–4.42 (m, 2H, H-3,

H-4), 4.81 (d, J=3.9 Hz, 1H, H-3’), 6.90–6.92 ppm (m, 3H, Harm);

¹³C NMR (100 MHz, CD₃CN): d=14.5 (CH₃), 23.4, 26.6 29.8, 30.0,

30.1, 32.7, 36.6 (CH₂nonanoic amide), 53.6 (C-2’), 57.7 (C-5), 59.0

(C-1), 60.1 (C-1’), 65.5 (2CH₂O), 70.0 (C-3), 71.2 (C-2), 71.6 (C-4),

72.9 (C-3’), 116.1, 118.2, 120.0 (CHarm), 134.8, 144.6, 144.7 (Cq

Carm), 174.6 ppm (C=O); IR (thin film): n˜ =3285, 2927, 2857, 1675,

1436, 1287, 1202, 1131, 1066, 1017 cm^À1; LC–MS: t_R=8.24 min

(linear gradient 10!60% B); ESI-MS: m/z=481.2 [M+H]⁺, 960.7

[2M+H]⁺, 982.9 [2M+Na]⁺; HRMS [QTOF, MH⁺] m/z calculated

for C₂₅H₄₁N₂O₇481.29083, found 481.29061.

pyrrolidine (5.20 g, 10.5 mmol, 70% yield over two steps). Analyti-

20

D

cal data was in full accordance with its d-enantiomer 67. ½a

=

34.98 (c=1, CHCl₃).

1,4-Dideoxy-1,4-imino-l-lyxitol hydrochloride (96): 1,4-Dideoxy-

1,4-benzylimino-2,3,5-tri-O-benzyl-l-lyxitol (69, 3.95 g, 8 mmol) was

subjected to the general hydrogenolysis procedure yielding title

compound (1.37 g, 8.0 mmol, quant.). Analytical data was in full ac-

cordance with its d-enantiomer 68. ½a²⁰=À28.58 (c=0.90, MeOH).

D

Compound 97: Compound 96 was reacted with mesylate 6 ac-

cording to the general procedure described above. Yield 0.075 g

(203 mmol, 51%); R_f=0.65 (EtOAc/tBuOH/AcOH/H₂O, 1:1:1:1, v/v/v/

Compound 40: Compound 98 was reacted with 55 according to

the general condensation protocol described above. Yield 0.012 g

v). ½a²⁰=80.2 (c=1.06 in MeOH); ¹H NMR (400 MHz, MeOD): d=

1

D

(23 mmol, 34%); H NMR (400 MHz, CD₃CN): d=2.59 (m, 2H, H₂-2’’),

2.45 (dd, J=5.4, 10.2 Hz, 1H, H-1a), 2.61 (dd, J=3.2, 12.7 Hz, 1H,

H-1’a), 2.74 (dt, 1H, J=4.6, 7.0 Hz, H-4), 2.95 (dd, J=9.1, 12.7 Hz,

1H, H-1’b), 3.03 (dd, J=3.1, 10.3 Hz, 1H, H-1b), 3.65 (dd, J=3.8,

11.3 Hz, 1H, H-5a), 3.74 (dd, J=5.0, 11.3 Hz, 1H, H-5b), 3.80 (ddd,

J=3.2, 6.6, 9.4 Hz, 1H, H-2’), 4.10 (td, J=3.2, 5.3 Hz, 1H, H-2), 4.21

(dd, J=5.0, 6.8 Hz, 1H, H-3), 4.24 (s, 4H, 2H₂ethylene), 5.11 (d,

J=6.6 Hz, 1H, H-3’), 6.86–6.89 ppm (m, 3H, Harm); ¹³C NMR

(100 MHz, MeOD): d=59.4 (C-1), 59.9 (C-1’), 60.9 (C-2’), 62.9 (C-5),

65.6 (2CH₂O), 68.4 (C-4), 71.8 (C-2), 73.4 (C-3), 82.4 (C-3’), 116.2,

118.6, 120.3 (CHarm), 132.9, 145.2, 145.6 (Cq Carm), 161.1 ppm (C=

O); IR (thin film): n˜ =3371, 2927, 2939, 1735, 1651, 1512, 1404,

1288, 1126, 1064, 1018 cm^À1; LC–MS: t_R=5.58 min (linear gradient

0!50% B); ESI-MS: m/z=367.0 [M+H]⁺, 733.0 [2M+H]⁺; HRMS

[QTOF, MH⁺] m/z calculated for C₁₇H₂₃N₂O₇367.14998, found

367.15010.

3.24 (dd, J=5.1, 11.9 Hz, 1H, H-1a), 3.35 (dd, J=4.1, 13.2 Hz, 1H, H-

1’a), 3.58 (brs, 1H, H-4), 3.65–3.76 (m, 5H, H-1’b, OMe, H-1b), 3.87

(dd, J=4.6, 12.7 Hz, 1H, H-5a), 3.94 (dd, J=5.8, 12.8 Hz, 1H H-5b),

3.98–4.06 (m, 2H, H₂propanoic acid), 4.19 (s, 4H, 2H₂ethylene),

4.36 (brs, 1H, H-2’), 4.42 (brs, 2H, H-2, H-3), 4.79 (d, J=3.6 Hz, 1H,

H-3’), 6.78–6.88 ppm (m, 7H, Harm); ¹³C NMR (100 MHz, CD₃CN):

d=36.7 (CH₂propanoic acid), 53.4 (C-2’), 56.4 (OMe), 57.9 (C-5),

58.9 (C-1), 60.2 (C-1’), 65.5 (2CH₂O), 65.6 (OCH₂propanoic acid),

70.0 (C-2/C-3), 71.3 (C-4), 71.5 (C-2/C-3), 72.9 (C-3’), 115.7, 116.1,

116.9, 118.1, 120.1 (CHarm), 134.3, 144.5, 144.6, 153.5, 155.3 (Cq

Carm), 175.3 ppm (C=O); IR (thin film): n˜ =3273, 2927, 2856, 1668,

1506, 1287, 1229, 1200, 1180, 1037 cm^À1; LC–MS: t_R=5.89 min

(linear gradient 10!60% B); ESI-MS: m/z=519.1 [M+H]⁺, 1036.6

[2M+H]⁺; HRMS [QTOF, MH⁺] m/z calculated for C₂₆H₃₅N₂O₉

519.23371, found 519.23342.

Compound 98: The oxazolidine in compound 97 was hydrolyzed

according to the saponification procedure described above. The

obtained imine 98 was immediately condensed with the hydroxy-

succinimide esters 10, 42 and 55 as described in the general con-

densing procedure; LC–MS: t_R=3.61 min (linear gradient 0!50%

B); ESI-MS: m/z=341.1 [M+H]⁺, 681.6 [2M+H]⁺.

Compound 99: Piperidine was reacted with mesylate 6 according

to the general procedure described above. Yield 0.045 g (140 mmol,

56%); R_f=0.80 (MeOH/EtOAc/NH₄OH 40:60:5, v/v/v). ½a²⁰=58.2

D

(c=0.45 in chloroform); ¹H NMR (400 MHz, CDCl₃): d=1.40–1.45

(m, 2H, H₂piperidine), 1.51–1.61 (m, 4H, H₂piperidine), 2.30–2.47

(m, 4H, NCH₂piperidine), 2.45 (dd, J=5.0, 12.5 Hz, 1H, H-1’a), 2.57

(dd, J=8.6, 12.5 Hz, 1H, H-1’b), 3.82 (dt, J=5.6, 8.5 Hz, 1H, H-2’),

4.26 (s, 4H, 2H₂ethylene), 5.04 (d, J=5.9 Hz, 1H, H-3’), 6.22 (s,

1H, NH), 6.83–6.90 ppm (m, 3H, Harm); ¹³C NMR (100 MHz, CDCl₃):

d=24.0 (CH₂), 25.7 (2CH₂), 54.9 (2CH₂N), 57.6 (C-2’), 63.0 (C-1’),

64.3 (2CH₂O), 81.3 (C-3’), 114.9, 117.5, 118.9 (CHarm), 131.7, 143.7,

143.9 (Cq Carm), 158.7 ppm (C=O); IR (thin film): n˜ =2935, 1752,

1508, 1288, 1067 cm^À1; LC–MS: t_R=5.05 min (linear gradient 0!

90% B); ESI-MS: m/z=319.1 [M+H]⁺, 636.6 [2M+H]⁺; HRMS

[QTOF, MH⁺] m/z calculated for C₁₇H₂₃N₂O₄319.16523, found

319.16532 (Scheme 6).

Compound 38: Compound 98 was reacted with 10 according to

the general condensation protocol described above. Yield 0.011 g

1

(19 mmol, 28%); H NMR (400 MHz, CD₃CN): d=1.28 (m, 2H, H₂-4’’),

1.44 (brs, 2H, H₂-3’’), 1.50 (brs, 6H, H₂adamantane), 1.62–1.73 (m,

6H, H₂adamantane), 1.91 (brs, 3H CH adamantane), 2.16 (brs, 2H,

H₂-2’’), 2.93 (brs, 2H, H₂adamantane), 3.27–3.34 (brm, 4H, H-1a,H-

1’a, H₂-5’’), 3.59–3.75 (m, 3H, H-1b, H-4, H-1’b), 3.85–3.96 (m, 2H,

H₂-5), 4.21 (s, 4H, 2H₂ethylene), 4.23 (m, 3H, H-2’, H-2, H-3), 4.78

(s, 1H, H-3’), 6.79–6.87 ppm (m, 3H, Harm); ¹³C NMR (100 MHz,

CD₃CN): d=23.1 (C-3’’), 29.3 (CH adamantane), 29.5 (C-4’’), 34.8 (Cq

adamantane), 36.2 (C-2’’), 37.9 (CH₂adamantane), 40.5 (CH₂ada-

mantane), 53.3 (C-2’), 57.8 (C-5), 58.8 (C-1), 60.1 (C-1’), 65.4 (2

CH₂O), 69.9 (C-2/C-3), 71.2 (C-4), 71.5 (C-2/C-3), 71.9 (C-5’’), 72.8 (C-

3’), 82.6 (OCH₂adamantane), 116.0, 117.9, 120.0 (CHarm), 135.0,

144.3, 144.5 (Cq Carm), 174.3 ppm (C=O); IR (thin film): n˜ =3287,

Compound 100: The oxazolidine in compound 99 was hydrolyzed

according to the saponification procedure described above. Yield

0.036 g (122 mmol, 87%); R_f=0.50 (MeOH/EtOAc/NH₄OH 16:4:1, v/

1

v/v). ½a²⁰=24.4 (c=0.71 in MeOH); H NMR (400 MHz, MeOD): d=

D

1.37–1.46 (m, 2H, H₂piperidine), 1.51–1.62 (m, 4H, H₂piperidine),

2.06 (dd, J=4.7, 12.6 Hz, 1H, H-1’a), 2.20 (dd, J=8.9, 12.6 Hz, 1H,

H-1’b), 2.28 (brs, 2H, NCH₂piperidine), 2.43 (brs, 2H, NCH₂piperi-

dine), 3.11 (ddd, J=4.7, 6.4, 8.8 Hz, 1H, H-2’), 4.22 (s, 4H, 2H₂eth-

ylene), 4.34 (d, J=6.4 Hz, 1H, H-3’), 6.75–6.82 ppm (m, 3H, Harm);

¹³C NMR (100 MHz, MeOD): d=25.3 (CH₂), 27.0 (2CH₂), 54.3 (C-2’),

56.1 (2CH₂N), 62.9 (C-1’), 65.6 (2CH₂O), 77.2 (C-3’), 116.6, 118.0,

120.7 (CHarm), 136.7, 144.5, 144.9 ppm (Cq Carm); IR (thin film):

2904, 2849, 1688, 1506, 1287, 1260, 1203, 1127, 1069, 1120 cm^À1

;

LC–MS: t_R=9.76 min (linear gradient 10!60% B); ESI-MS: m/z=

589.3 [M+H]⁺, 1177.0 [2M+H]⁺; HRMS [QTOF, MH⁺] m/z calculat-

ed for C₃₂H₄₉N₂O₈589.34834, found 589.34811.

Compound 39: Compound 98 was reacted with 52 according to

the general condensation protocol described above. Yield 0.023 g

(47 mmol, 70%); ¹H NMR (400 MHz, CD₃CN): d=0.87 (t, J=7.0 Hz,

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Scheme 6. Reagents and conditions: a) 6, K₂CO₃, DMF, 808C; b) LiOH, dioxane/H₂O, microwave, 1658C; c) 10, 52 or 55, DiPEA, DMF.

n˜ =3350, 2933, 1506, 1457, 1433, 1282, 1256, 1152, 1121,

1067 cm^À1; LC–MS: t_R=4.56 min (linear gradient 0!50% B); ESI-

MS: m/z=293.2 [M+H]⁺, 585.3 [2M+H]⁺; HRMS [QTOF, MH⁺] m/z

calculated for C₁₆H₂₅N₂O₃293.18597, found 293.18610.

Compound 43: Compound 100 was reacted with 55 according to

the general condensation protocol described above. Yield 0.012 g

1

(25 mmol, 63%). ½a²⁰=12.2 (c=0.24 in MeOH); H NMR (400 MHz,

D

MeOD): d=1.37–1.92 (m, 6H, 3H₂piperidine), 2.53–2.68 (m, 2H,

H₂-2’’), 2.92 (dt, J=2.6, 12.2 Hz, 1H, H piperidine), 3.01 (dt, J=2.9,

12.0 Hz, 1H, H piperidine), 3.31 (dd, J=6.0, 13.6 Hz, 1H, H-1’a), 3.42

(dd, J=2.8, 13.6 Hz, 1H, H-1’b), 3.47 (brd, J=11.7 Hz, 1H, H piperi-

dine), 3.74 (brs, 4H, H piperidine, OMe), 4.02 (dt, J=5.9, 9.4 Hz,

1H, H₂propanoic acid), 4.10 (dt, J=6.2, 9.5 Hz, 1H, H₂propanoic

acid), 4.18 (s, 4H, 2H₂ethylene), 4.50 (dt, J=3.1, 10.1 Hz, 1H, H-

2’), 4.76 (d, J=3.5 Hz, 1H, H-3’), 6.75–6.92 ppm (m, 7H, Harm);

¹³C NMR (100 MHz, MeOD): d=22.5 (CH₂piperidine), 24.2 (CH₂pi-

peridine), 37.2 (C-2’’), 52.1 (CH₂propanoic acid), 54.4 (CH₂piperi-

dine), 56.0 (CH₂piperidine), 56.2 (OMe), 60.7 (C-1’), 65.6 (2CH₂O),

66.0 (OCH₂propanoic acid), 73.5 (C-3’), 115.8, 116.3, 116.8, 118.0,

120.2 (CHarm), 134.3, 144.8, 144.9, 154.0, 155.8 (Cq Carm),

174.7 ppm (C=O); IR (thin film): n˜ =3361, 1670, 1508, 1458, 1286,

1199, 1130, 1066 cm^À1; LC–MS: t_R=5.61 min (linear gradient 10!

90% B); ESI-MS: m/z=471.3 [M+H]⁺, 963.2 [2M+Na]⁺; HRMS

[QTOF, MH⁺] m/z calculated for C₂₆H₃₅N₂O₆471.24896, found

471.24858.

Compound 41: Compound 100 was reacted with 10 according to

the general condensation protocol described above. Yield 0.008 g

(16 mmol, 39%). ½a²⁰=14.2 (c=0.17 in MeOH); H NMR (400 MHz,

1

D

MeOD): d=1.35–1.42 (m, 2H, H₂-4’’), 1.45–1.55 (m, 2H, H₂-3’’), 1.56

(brs, 6H, H₂adamantane), 1.66–1.86 (m, 10H, 3H₂adamantane,

2H₂piperidine), 1.94 (brs, 5H, 3CH adamantane, 1H₂piperi-

dine), 2.21 (m, 2H, H₂-2’’), 2.91 (dt, J=2.8, 12.4 Hz, 1H, H piperi-

dine), 2.95 (s, 2H, H₂adamantane), 3.03 (dt, J=3.6, 12.4 Hz, 1H, H

piperidine), 3.28–3.35 (m, 3H, H-1’a, H₂-5’’), 3.40 (dd, J=3.0, 13.6 Hz,

1H, H-1’b), 3.47 (brd, J=12.5 Hz, 1H, H piperidine), 3.79 (brd, J=

12.5 Hz, 1H, H piperidine), 4.21 (s, 4H, 2H₂ethylene), 4.47 (dt, J=

3.2, 10.2 Hz, 1H, H-2’), 4.76 (d, J=3.4 Hz, 1H, H-3’), 6.78–6.91 ppm

(m, 3H, Harm); ¹³C NMR (100 MHz, MeOD): d=22.6 (CH₂piperidine),

23.5 (C-3’’), 24.1 (CH₂piperidine), 29.8 (CH adamantane), 30.2 (C-4’’),

35.2 (Cq adamantane), 36.7 (C-2’’), 38.4 (CH₂adamantane), 40.9 (CH₂

adamantane), 51.9 (C-2’), 54.1 (CH₂piperidine), 56.2 (CH₂piperidine),

60.9 (C-1’), 65.6 (2CH₂O), 72.2 (C-5’’), 73.5 (C-3’), 82.1 (OCH₂ada-

mantane), 116.2, 118.1, 120.0 (CHarm), 135.5, 144.7, 144.9 (Cq Carm),

177.3 ppm (C=O); IR (thin film): n˜ =3369, 2902, 2846, 1670, 1508,

1286, 1207, 1068 cm^À1; LC–MS: t_R=8.04 min (linear gradient 10!

90% B); ESI-MS: m/z=541.3 [M+H]⁺, 1103.3 [2M+Na]⁺; HRMS

[QTOF, MH⁺] m/z calculated for C₃₂H₄₉N₂O₅541.36360, found

541.36321.

Compound 101: Morpholine was reacted with mesylate 6 accord-

ing to the general procedure described above. Yield 0.050 g

(155 mmol, 62%); R_f=0.80 (MeOH/EtOAc/NH₄OH 40:60:5, v/v/v).

1

½a²⁰=47.2 (c=0.50 in chloroform); H NMR (400 MHz, CDCl₃): d=

D

2.41 (m, 2H, NH₂morpholine), 2.47–2.53 (m, 4H, H₂morpholine),

2.52 (dd, J=6.0, 13.0 Hz, 1H, H-1’a), 2.58 (dd, J=7.7, 12.5 Hz, 1H,

H-1’b), 3.65–3.71 (m, 4H, 2OCH₂morpholine), 3.83 (q, J=6.2 Hz,

1H, H-2’), 4.26 (s, 4H, 2H₂ethylene), 5.10 (d, J=5.8 Hz, 1H, H-3’),

6.29 (s, 1H, NH), 6.83–6.90 ppm (m, 3H, Harm); ¹³C NMR (100 MHz,

CDCl₃): d=53.8 (2CH₂N morpholine), 57.4 (C-2’), 62.4 (C-1’), 64.2

(2CH₂O), 66.7 (2CH₂O morpholine), 81.3 (C-3’), 114.9, 117.6,

118.8 (CHarm), 131.6, 143.7, 143.9 (Cq Carm), 158.7 ppm (C=O); IR

(thin film): n˜ =3277, 2859, 2748, 1659, 1508, 1287, 1112, 1067,

1007 cm^À1; LC–MS: t_R=4.77 min (linear gradient 0!90% B); ESI-

MS: m/z=321.1 [M+H]⁺; HRMS [QTOF, MH⁺] m/z calculated for

C₁₆H₂₁N₂O₅321.14450, found 321.14456.

Compound 42: Compound 100 was reacted with 52 according to

the general condensation protocol described above. Yield 0.006 g

(15 mmol, 37%). ½a²⁰=17.1 (c=0.13 in MeOH); H NMR (400 MHz,

1

D

MeOD): d=0.91 (t, J=6.9 Hz, 3H, CH₃), 1.14–1.99 (m, 18H, 6H₂

nonanoic amide, 3H₂piperidine), 2.15 (m, 2H, H₂-2’’), 2.91 (dt, J=

2.5, 12.3 Hz, 1H, H piperidine), 3.05 (dt, J=3.0, 12.3 Hz, 1H, H pi-

peridine), 3.32 (dd, J=3.8, 13.6 Hz, 1H, H-1’a), 3.39 (dd, J=3.0,

13.6 Hz, 1H, H-1’b), 3.47 (brd, J=12.6 Hz, 1H, H piperidine), 3.80

(brd, J=12.6 Hz, 1H, H piperidine), 4.21 (s, 4H, 2H₂ethylene),

4.47 (dt, J=3.1, 10.0 Hz, 1H, H-2’), 4.76 (d, J=3.4 Hz, 1H, H-3’),

6.77–6.91 ppm (m, 3H, Harm); ¹³C NMR (100 MHz, MeOD): d=14.4

(CH₃), 22.6, 23.7, 24.1, 26.7, 30.2, 30.3, 30.4, 33.0, 37.0 (2CH₂piper-

idine, 7CH₂nonanoic amide), 51.9 (C-2’), 54.1 (CH₂piperidine),

56.2 (CH₂piperidine), 61.0 (C-1’), 65.6 (2CH₂O), 73.5 (C-3’), 116.2,

118.0, 120.0 (CHarm), 135.5, 144.7, 144.9 (Cq Carm), 177.5 ppm (C=

O); IR (thin film): n˜ =3342, 2927, 2856, 1670, 1508, 1458, 1286,

1199, 1134, 1068 cm^À1; LC–MS: t_R=7.05 min (linear gradient 10!

90% B); ESI-MS: m/z=433.2 [M+H]⁺, 864.6 [2M+H]⁺; HRMS

[QTOF, MH⁺] m/z calculated for C₂₅H₄₁N₂O₄433.30608, found

433.30569.

Compound 102: The oxazolidine in compound 101 was hydro-

lyzed according to the saponification procedure described above.

Yield 0.036 g (115 mmol, 74%); R_f=0.40 (MeOH/EtOAc/NH₄OH

16:4:1, v/v/v). ½a²⁰=31.1 (c=0.68 in MeOH); ¹H NMR (400 MHz,

D

MeOD): d=2.07 (dd, J=4.3, 12.5 Hz, 1H, H-1’a), 2.23 (dd, J=9.5,

12.5 Hz, 1H, H-1’b), 2.26–2.32 (m, 2H, NH₂morpholine), 2.45–2.50

(m, 2H, NH₂morpholine), 3.11 (ddd, J=4.3, 6.6, 10.2 Hz, 1H, H-2’),

2.60–2.70 (m, 4H, 2OCH₂morpholine), 4.23 (s, 4H, 2H₂ethyl-

ene), 4.32 (d, J=6.6 Hz, 1H, H-3’), 6.76–6.83 ppm (m, 3H, Harm);

¹³C NMR (100 MHz, MeOD): d=54.4 (C-2’), 55.1 (2CH₂N morpho-

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line), 62.3 (C-1’), 65.6 (2CH₂O), 68.0 (2CH₂O morpholine), 76.8

(C-3’), 116.5, 118.0, 120.6 (CHarm), 136.8, 144.6, 144.9 ppm (Cq

Carm); IR (thin film): n˜ =3370, 2871, 1590, 1506, 1457, 1283, 1258,

1112, 1067 cm^À1; LC–MS: t_R=4.33 min (linear gradient 0!50% B);

ESI-MS: m/z=295.3 [M+H]⁺, 589.1 [2M+H]⁺; HRMS [QTOF, MH⁺]

m/z calculated for C₁₅H₂₃N₂O₄295.16523, found 295.16537.

Compound 103: Pyrrolidine was reacted with mesylate 6 accord-

ing to the general procedure described above. Yield 0.042 g

(137 mmol, 55%); R_f=0.75 (MeOH/EtOAc/NH₄OH 40:60:5, v/v/v).

½a²⁰=60.8 (c=0.42 in chloroform); H NMR (400 MHz, CDCl₃): d=

1

D

1.71–1.79 (m, 4H, 2H₂pyrrolidine), 2.46–2.57 (m, 4H, 2NH₂pyr-

rolidine), 2.58 (dd, J=4.9, 12.1 Hz, 1H, H-1’a), 2.80 (dd, J=4.9,

12.1 Hz, 1H, H-1’b), 3.78 (dt, J=5.5, 8.4 Hz, 1H, H-2’), 4.26 (s, 4H,

2H₂ethylene), 5.07 (d, J=6.0 Hz, 1H, H-3’), 6.31 (s, 1H, NH), 6.83–

6.89 ppm (m, 3H, Harm); ¹³C NMR (100 MHz, CDCl₃): d=23.5 (2

CH₂pyrrolidine), 54.2 (2CH₂N pyrrolidine), 59.3 (C-2’), 59.9 (C-1’),

64.3 (2CH₂O), 81.3 (C-3’), 114.9, 117.5, 118.9 (CHarm), 131.8, 143.7,

143.9 (Cq Carm), 158.7 ppm (C=O); IR (thin film): n˜ =3372, 2933,

2751, 1654, 1508, 1287, 1067, 1008 cm^À1; LC–MS: t_R=4.90 min

(linear gradient 0!90% B); ESI-MS: m/z=305.1 [M+H]⁺; HRMS

[QTOF, MH⁺] m/z calculated for C₁₆H₂₁N₂O₄305.14958, found

305.14972.

Compound 44: Compound 102 was reacted with 10 according to

the general condensation protocol described above. Yield 0.018 g

(31 mmol, 82%). ½a²⁰=14.1 (c=0.27 in MeOH); H NMR (400 MHz,

1

D

MeOD): d=1.31–1.40 (m, 2H, H₂-4’’), 1.44–1.53 (m, 2H, H₂-3’’), 1.56

(brs, 6H, 3H₂adamantane), 1.67–1.78 (m, 6H, 3H₂adaman-

tane), 1.95 (brs, 3H, 3CH adamantane), 2.19 (m, 2H, H₂-2’’), 2.95

(s, 2H, H₂adamantane), 3.10–3.50 (m, 8H, 2NCH₂morpholino, H₂-

1’, H₂-5’’), 3.60–3.4.15 (m, 4H, 2OCH₂morpholino), 4.22 (s, 4H, 2

H₂ethylene), 4.47 (dt, J=3.2, 9.6 Hz, 1H, H-2’), 4.76 (d, J=2.8 Hz,

1H, H-3’), 6.78–6.92 ppm (m, 3H, Harm); ¹³C NMR (100 MHz,

MeOD): d=23.5 (C-3’’), 29.8 (CH adamantane), 30.1 (C-4’’), 35.2 (Cq

adamantane), 36.7 (C-2’’), 38.4 (CH₂adamantane), 40.9 (CH₂ada-

mantane), 51.4 (C-2’), 54.3 (NCH₂morpholino), 61.3 (C-1’), 64.8

(OCH₂morpholino), 65.7 (2CH₂O), 72.2 (C-5’’), 73.4 (C-3’), 83.1

(OCH₂adamantane), 116.2, 118.0, 120.0 (CHarm), 135.5, 144.7, 144.9

(Cq Carm), 177.3 ppm (C=O); IR (thin film): n˜ =3369, 2902, 2848,

1670, 1508, 1286, 1199, 1136, 1066 cm^À1; LC–MS: t_R=7.48 min

(linear gradient 10!90% B); ESI-MS: m/z=543.3 [M+H]⁺, 1107.4

[2M+Na]⁺; HRMS [QTOF, MH⁺] m/z calculated for C₃₁H₄₇N₂O₆

543.34286, found 543.34257.

Compound 104: The oxazolidine in compound 103 was hydro-

lyzed according to the saponification procedure described above.

Yield 0.034 g (122 mmol, 89%); R_f=0.30 (MeOH/EtOAc/NH₄OH

16:4:1, v/v/v). ½a²⁰=21.5 (c=0.68 in MeOH); ¹H NMR (400 MHz,

D

MeOD): d=1.75–1.82 (m, 4H, 2H₂pyrrolidine), 2.26 (dd, J=4.1,

12.3 Hz, 1H, H-1’a), 2.42–2.51 (m, 2H, H₂pyrrolidine), 2.56 (dd, J=

9.5, 12.4 Hz, 1H, H-1’b), 2.58–2.65 (m, 2H, H₂pyrrolidine), 3.10

(ddd, J=4.2, 6.4, 10.3 Hz, 1H, H-2’), 4.23 (s, 4H, 2H₂ethylene),

4.38 (d, J=6.4 Hz, 1H, H-3’), 6.76–6.84 ppm (m, 3H, Harm);

¹³C NMR (100 MHz, MeOD): d=24.3 (2CH₂pyrrolidine), 55.3 (2

CH₂N pyrrolidine), 56.5 (C-2’), 59.6 (C-1’), 65.6 (2CH₂O), 76.1 (C-3’),

116.5, 118.1, 120.6 (CHarm), 136.5, 144.6, 144.9 ppm (Cq Carm); IR

(thin film): n˜ =3350, 2877, 1590, 1507, 1458, 1284, 1067 cm^À1; LC–

MS: t_R=4.14 min (linear gradient 0!50% B); ESI-MS: m/z=279.3

[M+H]⁺, 557.3 [2M+H]⁺; HRMS [QTOF, MH⁺] m/z calculated for

C₁₅H₂₃N₂O₃279.17032, found 279.17032.

Compound 45: Compound 102 was reacted with 52 according to

the general condensation protocol described above. Yield 0.013 g

1

(24 mmol, 62%). ½a²⁰=16.1 (c=0.26 in MeOH); H NMR (400 MHz,

D

MeOD): d=0.91 (t, J=7.0 Hz, 3H, CH₃), 1.12–1.47 (m, 12H, 6H₂

nonanoic amide), 2.15 (m, 2H, H₂-2’’), 3.10–4.05 (m, 10H, 2NCH₂

morpholino, 2OCH₂morpholino H₂-1’), 4.21 (s, 4H, 2H₂ethyl-

ene), 4.50 (dt, J=3.6, 9.4 Hz, 1H, H-2’), 4.77 (d, J=3.2 Hz, 1H, H-3’),

6.77–6.91 ppm (m, 3H, Harm); ¹³C NMR (100 MHz, MeOD): d=14.4

(CH₃), 23.7, 26.6, 30.2, 30.3, 30.4, 33.0, 37.0 (CH₂nonanoic amide),

51.4 (C-2’), 61.3 (C-1’), 64.8 (OCH₂morpholino, NCH₂morpholino),

65.6 (2CH₂O), 73.5 (C-3’), 116.2, 118.0, 120.0 (CHarm), 135.5, 144.7,

144.9 (Cq Carm), 177.5 ppm (C=O); IR (thin film): n˜ =3352, 2927,

2858, 1652, 1508, 1458, 1286, 1200, 1134, 1066 cm^À1; LC–MS: t_R=

6.70 min (linear gradient 10!90% B); ESI-MS: m/z=435.3 [M+H]⁺,

891.2 [2M+Na]⁺; HRMS [QTOF, MH⁺] m/z calculated for C₂₄H₃₉N₂O₅

435.28535, found 435.28499.

Compound 47: Compound 104 was reacted with 10 according to

the general condensation protocol described above. Yield 0.010 g

(15 mmol, 37%). ½a²⁰=14.7 (c=0.19 in MeOH); H NMR (400 MHz,

1

D

MeOD): d=1.38 (dt, J=7.0, 14.1 Hz, 2H, H₂-4’’), 1.42 (dt, J=7.1,

14.2 Hz, 2H, H₂-3’’), 1.56 (brs, 6H, H₂adamantane), 1.67–1.78 (m,

6H, 3H₂adamantane), 1.95 (brs, 3H, 3CH adamantine) 2.02 (m,

2H, H₂pyrrolidine), 2.15 (m, 2H, H₂pyrrolidine), 2.20 (dt, J=6.5,

14.2 Hz, 2H, H₂-2’’), 2.95 (s, 2H, H₂adamantane), 3.16 (m, 2H, H₂

pyrrolidine), 3.33 (t, J=6.3 Hz, 2H, H₂-5’’), 3.38–3.58 (m, 2H, H₂-1’),

3.63 (m, 1H, pyrrolidine), 3.79 (m, 1H, pyrrolidine), 4.21 (s, 4H, 2

H₂ethylene), 4.44 (dt, J=3.2, 10.2 Hz, 1H, H-2’), 4.77 (d, J=3.1 Hz,

1H, H-3’), 6.78–6.91 ppm (m, 3H, Harm); ¹³C NMR (100 MHz,

MeOD): d=23.5 (C-3’’), 24.0 (CH₂pyrrolidine), 29.8 (CH adaman-

tane), 30.2 (C-4’’), 36.7 (C-2’’), 38.4 (CH₂adamantane), 40.9 (CH₂

adamantane), 53.2 (C-2’), 55.4 (CH₂pyrrolidine), 56.9 (CH₂pyrroli-

dine), 58.6 (C-1’), 65.6 (2CH₂O), 72.2 (C-5’’), 73.4 (C-3’), 83.1 (OCH₂

adamantane), 116.2, 118.0, 120.0 (CHarm), 135.6, 144.6, 144.9 (Cq

Carm), 177.1 ppm (C=O); IR (thin film): n˜ =3394, 1750, 1203, 1132,

1064 cm^À1; LC–MS: t_R=7.60 min (linear gradient 10!90% B); ESI-

MS: m/z=527.3 [M+H]⁺, 1052.9 [2M+H]⁺; HRMS [QTOF, MH⁺]

m/z calculated for C₃₁H₄₇N₂O₅527.34795, found 527.34763.

Compound 46: Compound 102 was reacted with 55 according to

the general condensation protocol described above. Yield 0.013 g

(20 mmol, 54%). ½a²⁰=9.8 (c=0.37 in MeOH); ¹H NMR (400 MHz,

D

MeOD): d=2.60 (t, J=6.1 Hz, 2H, H₂-2’’ propanoic acid), 3.21 (brs,

2H, H₂morpholino), 3.41 (dd, J=10.2, 13.5 Hz, 1H, H-1’a), 3.50 (dd,

J=2.9, 13.5 Hz, 1H, H-1’b), 3.62–9.93 (brm, 9H, 3H₂morpholino,

OMe), 4.00 (dd, J=6.0, 9.4 Hz, 1H, H-3’’a propanoic acid), 4.08 (dd,

J=6.2, 9.4 Hz, 1H, H-3’’b propanoic acid), 4.17 (s, 4H, 2H₂ethyl-

ene), 4.53 (dt, J=3.0, 10.1 Hz, 1H, H-2’), 4.78 (d, J=3.3 Hz, 1H, H-3’),

6.74–6.92 ppm (m, 7H, Harm); ¹³C NMR (100 MHz, MeOD): d=37.2

(C-2’’), 51.7 (C-2’), 56.1 (OMe), 61.1 (C-1’), 64.8 (OCH₂morpholino,

NCH₂morpholino), 65.6 (2CH₂O), 65.9 (OCH₂propanoic acid), 73.5

(C-3’), 115.7, 116.2, 116.8, 118.0, 120.1 (CHarm), 135.3, 144.7, 144.9,

154.0, 155.8 (Cq Carm), 174.7 ppm (C=O); IR (thin film): n˜ =3359,

1652, 1506, 1458, 1286, 1200, 1130, 1066 cm^À1; LC–MS: t_R=5.31 min

(linear gradient 10!90% B); ESI-MS: m/z=473.2 [M+H]⁺, 944.4

[2M+H]⁺, 967.0 [2M+Na]⁺; HRMS [QTOF, MH⁺] m/z calculated for

C₂₅H₃₃N₂O₇473.22823, found 473.22789.

Compound 3: Compound 104 was reacted with 52 according to

the general condensation protocol described above. Yield 0.011 g

1

(21 mmol, 53%). ½a²⁰=18.6 (c=0.23 in MeOH); H NMR (400 MHz,

D

MeOD): d=0.91 (t, J=7.0 Hz, 3H, CH₃), 1.14–1.50 (m, 12H, 6H₂

nonanoic amide), 1.95–2.22 (m, 6H, H₂-2’’, 2H₂pyrrolidine), 3.11–

3.20 (m, 2H, H₂pyrrolidine), 3.41 (dd, J=3.6, 13.2 Hz, 1H, H-1’a),

3.47 (dd, J=10.0, 13.2 Hz, 1H, H-1’b), 3.64 (brs, 1H, H pyrrolidine),

3.78 (brs, 1H, H pyrrolidine), 4.21 (s, 4H, 2H₂ethylene), 4.44 (dt,

J=3.5, 10.0 Hz, 1H, H-2’), 4.77 (d, J=3.2 Hz, 1H, H-3’), 6.77–

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6.90 ppm (m, 3H, Harm); ¹³C NMR (100 MHz, MeOD): d=14.4 (CH₃),

23.7, 24.0, 26.7, 30.2, 30.3, 30.5, 31.1, 33.0, 37.1 (2CH₂pyrrolidine,

7CH₂nonanoic amide), 53.0 (C-2’), 55.4 (CH₂pyrrolidine), 56.9

(CH₂pyrrolidine), 58.6 (C-1’), 65.6 (2CH₂O), 73.4 (C-3’), 116.2,

118.0, 120.0 (CHarm), 135.6, 144.6, 144.8 (Cq Carm), 177.3 ppm (C=

O); IR (thin film): n˜ =3352, 2931, 2856, 1670, 1508, 1286, 1200,

1134, 1068 cm^À1; LC–MS: t_R=6.61 min (linear gradient 10!90% B);

ESI-MS: m/z=419.3 [M+H]⁺, 836.7 [2M+H]⁺; HRMS [QTOF, MH⁺]

m/z calculated for C₂₄H₃₉N₂O₄419.29043, found 419.29007.

2000 , 355 , 148 1 –1 485; b) D. Elstein, A. Dweck, D. Attias, I. Hadas-Hal-

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[7] a) T. Wennekes, R. J. B. H. N. van den Berg, W. Donker, G. A. van der

Marel, A. Strijland, J. M. F. G. Aerts, H. S. Overkleeft, J. Org. Chem. 2007 ,

72 , 108 8 –1 097; b) T. Wennekes, A. J. Meijer, A. K. Groen, R. G. Boot, J. E.

Groener, M. van Eijk, R. Ottenhoff, N. Bijl, K. Ghauhalari, H. Song, T. J.

Shea, H. Liu, N. Yew, D. Copeland, R. J. B. H. N. van den Berg, G. A.

van der Marel, H. S. Overkleeft, J. M. F. G. Aerts, J. Med. Chem. 2010 , 53 ,

68 9 –6 98; c) A. Ghisaidoobe, P. Bikker, A. C. J. de Bruin, F. D. Godschalk,

E. Rogaar, M. C. Guijt, P. Hagens, J. M. Halma, S. M. van ‘t Hart, S. B. Luit-

jens, V. H. S. van Rixtel, M. Wijzenbroek, T. Zweegers, W. E. Donker-Koop-

man, A. Strijland, R. Boot, G. van der Marel, H. S. Overkleeft, J. M. F. G.

Aerts, R. J. B. H. N. van den Berg, ACS Med. Chem. Lett. 2011 , 2 , 11 9 –

123; d) N. Ardes-Guisot, D. S. Alonzi, G. Reinkensmeier, T. D. Butters, C.

Norez, F. Becq, Y. Shimada, S. Nakagawa, A. Kato, Y. BlØriot, M. Sollo-

goub, B. Vauzeilles, Org. Biomol. Chem. 2011 , 9 , 537 3 –5 388; e) C. Bou-

cheron, V. Desvergnes, P. Compain, O. R. Martin, A. Lavi, M. Mackeen,

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[8] N-Alkylated deoxynojirimycin derivatives have recently been pursued as

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[9] a) H. Nojiri, M. Stroud, S. Hakommori, J. Biol. Chem. 1991, 266, 4531–

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Compound 48: Compound 104 was reacted with 55 according to

the general condensation protocol described above. Yield 0.012 g

1

(21 mmol, 53%). ½a²⁰=14.0 (c=0.25 in MeOH); H NMR (400 MHz,

D

MeOD): d=1.98 (brs, 2H, H₂pyrrolidine), 2.12 (brs, 2H, H₂pyrroli-

dine), 2.62 (t, J=6.2 Hz, 2H, H₂-2’’), 3.11–3.19 (m, 2H, pyrrolidine),

3.41–3.19 (m, 2H, H₂-1’), 3.65 (brs, 1H, H pyrrolidine), 3.74 (brs, 3H,

H piperidine, OMe), 3.77 (brs, 1H, H pyrrolidine), 4.02 (dt, J=6.1,

9.4 Hz, 1H, propanoic acid), 4.08 (dt, J=6.2, 9.5 Hz, 1H, propanoic

acid), 4.17 (s, 4H, 2H₂ethylene), 4.47 (dt, J=4.1, 7.8 Hz, 1H, H-2’),

4.77 (d, J=3.2 Hz, 1H, H-3’), 6.74–6.91 ppm (m, 7H, Harm);

¹³C NMR (100 MHz, MeOD): d=23.9 (CH₂pyrrolidine), 24.0 (CH₂pyr-

rolidine), 31.1 (C-2’’), 53.4 (C-2’), 55.6 (CH₂pyrrolidine), 56.1 (OMe),

56.8 (CH₂pyrrolidine), 58.4 (C-1’), 65.6 (2CH₂O), 65.9 (OCH₂propa-

noic acid), 73.5 (C-3’), 115.7, 116.2, 116.8, 118.0, 120.1, 120.6

(CHarm), 135.4, 144.7, 144.9, 154.0, 155.8 (Cq Carm), 174.4 ppm (C=

O); IR (thin film): n˜ =3377, 1670, 1508, 1286, 1200, 1130,

1066 cm^À1; LC–MS: t_R=5.24 min (linear gradient 10!90% B); ESI-

MS: m/z=457.2 [M+H]⁺, 912.3 [2M+H]⁺; HRMS [QTOF, MH⁺] m/z

calculated for C₂₅H₃₃N₂O₆457.23331, found 457.23299.

Acknowledgements

The authors are grateful for financial support from the Nether-

lands Organization for Scientific Research (NWO-CW) and the Eu-

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2330.

Keywords: acid glucosylceramidase · ceramide analogues ·

deoxynojirimycin

·

glucosylceramide synthase

·

neutral

glucosylceramidase

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Received: September 7, 2015

Published online on October 23, 2015

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ꢀ 2015 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim

Article Doi

Synthesis and Evaluation of Hybrid Structures Composed of Two Glucosylceramide Synthase Inhibitors

DOI: 10.1002/cmdc.201500407

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