Synthesis of calystegine B2, B3, and B4 analogues: Mapping the structure-glycosidase inhibitory activity relationships in the 1-deoxy-6-oxacalystegine series

FULL PAPER

Synthesis of Calystegine B₂, B₃, and B₄Analogues: Mapping the

Structure-Glycosidase Inhibitory Activity Relationships in the

1-Deoxy-6-oxacalystegine Series

[a]

[b]

´

M. Isabel Garcıa-Moreno, Carmen Ortiz Mellet,* and Jose M. Garcıa Fernandez*

Keywords: Azasugars / Calystegines / Carbohydrates / Glycosidases / Imino sugars

A practical synthesis of ring-modified calystegine analogues

with a 6-oxa-nor-tropane structure has been developed. The

methodology relies on the ability of the masked carbonyl

group of hexose precursors to act as the electrophilic target

for the nitrogen atom of pseudoamide (urea or thiourea)

groups located at the C-5 position through the open-chain

aldehyde form. The resulting piperidine species undergoes

spontaneous intramolecular glycosylation reaction involving

6-OH provided that the resulting bicyclic aminoacetal fulfils

the anomeric effect. The hydroxylation profile of the imino

sugar glycomimetics thus obtained can be modified by judi-

addition of water to the resulting carbodiimide, respectively.

Attempts to prepare analogues with the unnatural 3-epi-(+)-

calystegine B₂hydroxylation profile from

L-talofuranose

(thio)ureas by this methodology led, however, to equilibrium

mixtures of the furanose anomers, with only traces of the nor-

tropane form. Evaluation of the inhibitory activity of the

whole series of calystegine analogues against several glycos-

idases indicated that the main structural requirements for

strong and specific inhibition of bovine liver β-glucosidase/

β-galactosidase are the all-equatorial orientation of the triol

system at the piperidine ring, the presence of a lipophilic

cious choice of the monosaccharide template. The validity of substituent at the nitrogen atom and the location of the intra-

the strategy has been demonstrated by the preparation of N-

thiocarbamoyl and N-carbamoyl derivatives of 1-deoxy-6-

molecular aminoacetal oxygen atom at the 6-position of the

nor-tropane core. On the basis of these data, a structural ana-

logy of 6-oxa-(+)-calystegine B₂derivatives with the natural

calystegine C₁has been established and a 1-azasugar inhibi-

oxa-(+)-calystegine B₂, (−)-B₄, (+)-B₃, and (−)-B₂from

L-ido,

L

-gulo, -altro, and -ido precursors. The requested thioureas

L

D

and ureas were obtained from 5-amino- or 5-azido-5-deox- tion mode is proposed.

yhexofuranose derivatives by a coupling reaction with isothi-

ocyanates or a tandem Staudinger−aza-Wittig-type reaction ( Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim,

with triphenylphosphane and an isothiocyanate followed by

Germany, 2004)

Introduction

have been extensively investigated,^[5Ϫ10]the calystegines

have been significantly less explored, and the structural

basis for glycosidase inhibition by this group of alkaloids

has been only partially established.

The calystegines are a recently discovered family of plant

nor-tropane alkaloids bearing three (calystegine A), four

(calystegine B) or five hydroxyl groups (calystegine C).^[1Ϫ3]

Some of the most abundant calystegines in plants are ca-

Similarly to other polyhydroxy alkaloids with a structural lystegine B₂, B₃, B₄, and C₁(Figure 1). The first of these is

resemblance to sugars (imino sugars, ‘‘azasugars’’),^[4]many a potent inhibitor of β-glucosidases and α-galactosidases,

calystegines exhibit strong and specific glycoside hydrolase while the epimeric calystegines B₃and B₄are moderate in-

inhibitory activity, particularly for glucosidases and galac- hibitors of trehalases.^[11]Calystegine C₁, which has a hy-

tosidases, and are therefore interesting lead compounds for droxylation pattern around the piperidine ring identical to

pharmaceutical research. However, in comparison to other calystegine B₂but bearing an additional hydroxyl substitu-

sugar mimics with nitrogen in the ring, such as polyhydroxy ent at the C-6 position on the pyrrolidine ring, is also a

pyrrolidine, piperidine, pyrrolizidine and indolizidine, which potent β-glucosidase inhibitor, although it is inactive

against α-galactosidase.^[11]A binding model has been pro-

[a]

posed that invokes charge interactions with the carboxylic

groups of the active site by analogy with the presumed gly-

cosyl oxocarbenium cation intermediate of enzymatic glyco-

side hydrolysis.^[12]This situation would be similar to that

generally accepted for other azasugar glycomimetics such

as 1-deoxynojirimycin. However, in the light of recent

mechanistic studies on the β-glucosidase reaction,^[13Ϫ15]the

´

Departamento de Quımica Organica, Facultad de Quımica,

Universidad de Sevilla,

Apartado 553, 41071 Sevilla, Spain

Fax: (internat.) ϩ34-95-4624960

E-mail: mellet@us.es

[b]

´

Instituto de Investigaciones Quımicas, CSIC,

´

Americo Vespucio s/n, Isla de la Cartuja, Sevilla, Spain

Fax: (internat.) ϩ34-95-4460565

E-mail: jogarcia@iiq.csic.es

Eur. J. Org. Chem. 2004, 1803Ϫ1819

DOI: 10.1002/ejoc.200300731

 2004 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim

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M. I. Garcıa-Moreno, C. Ortiz Mellet, J. M. Garcıa Fernandez

FULL PAPER

remarkable β-anomeric selectivity of calystegines B₂and C₁sp²-azasugar-type glycomimetics^[4]having all possible epim-

would rather suggest a correspondence with an anomeric eric hydroxylation profiles at the piperidine ring, including

carbocation species. Calystegines might then be regarded as calystegine B₂, B₃, B₄, and 3-epi-B₂analogues. The latter

rigid 1-azasugar-type glycomimetics, of which the potent β- are shown to exist only in a very minor proportion in aque-

glucosidase inhibitor isofagomine is a paradigmatic ex- ous solution. The inhibitory selectivity and potency re-

ample (Figure 1).^[16,17]

lationships have been assayed in order to map the geometri-

cal requirements for biological activity in this family of

compounds.

Results and Discussion

The general synthetic strategy developed for the assembly

of the bicyclic skeleton of 6-oxacalystegines starts from

hexose precursors and is depicted in Figure 3. It consists of

an intramolecular two-step tandem reaction involving

sequential nucleophilic addition of a C-5 located pseudo-

amide-type (urea or thiourea) nitrogen atom to the masked

aldehyde group of the monosaccharide template, to give a

transient reducing piperidine derivative which undergoes

spontaneous intramolecular glycosidation to form the pri-

mary hydroxyl group. The driving force for the whole trans-

formation is probably the increase in stability due to the

efficient delocalization interaction between the π-type lone-

pair orbital of the sp²-hybridized nitrogen atom in the

ground state of N-(thio)carbonyl functionalities and the σ*-

antibonding orbital of the contiguous CϪO bond, which is

axially anchored in the bridged 1,3-O,N-heterobicyclic sys-

tem, fitting the anomeric effect.^[29]Hydroxylation profiles

of stereochemical complementarity with the natural (ϩ)-ca-

lystegine B₂, (Ϫ)-calystegine B₄, and (ϩ)-calystegine B₃im-

ply the -ido, -gulo, and -altro configuration, respectively,

of the starting monosaccharide precursors, while in the

cases of derivatives having the 3-epi-(ϩ)-calystegine B₂and

(Ϫ)-calystegine B₂stereochemistry, hitherto not isolated

from natural sources, the -talo and -ido configurational

arrangements are required. In all cases, the key 5-deoxy-5-

(thio)ureidohexofuranose intermediates were obtained

through a reaction sequence that involved the inversion of

the configuration at C-5 of the corresponding epimeric sug-

ars at this position, that is -glucose, -mannose, -galac-

tose, -allose, and -glucose derivatives, respectively, which

are much more readily accessible from commercially avail-

able monosaccharides.

Figure 1. Structure of calystegines in comparison with that of 1-

deoxynojirimycin and isofagomine

Several approaches to the synthesis of the natural calyste-

gines have been reported in the last few years.^[18Ϫ21]How-

ever, examples of unnatural calystegine analogues are much

rarer,^[22,23]and no systematic modifications of the topo-

graphical properties for structure-activity studies have been

reported so far, probably due to the instability of the ami-

noacetal function characteristic of the calystegine bicyclic

core. We have recently found that a subtle change in the

structure of azasugars — replacing the sp³-imino nitrogen

by a pseudoamide-type nitrogen atom with substantial sp²

character — leads to a dramatic increase of the orbital con-

tribution to the anomeric effect at the aminoacetal pseudo-

anomeric center, resulting in a total preference for the axial

orientation of the oxygen substituent and a notably en-

hanced stability.^[24Ϫ28]This principle has been translated

into a practical synthesis of calystegine B₂analogues in

which the hemiaminal bridgehead hydroxyl has been re-

placed by an endocyclic aminoacetal group, namely N-(thi-

o)carbamoyl-1-deoxy-6-oxa-(ϩ)-calystegine B₂derivatives

(1Ϫ6; Figure 2).^[29,30]Some of the members of this new

class of compounds (e.g., 1 and 2) have been shown to be

more potent and selective β-glucosidase inhibitors than the

parent natural product, their inhibitory activity being

strongly dependent on the nature of the exocyclic substitu-

ent. Here we report on the preparation of 6-oxacalystegine

Synthesis of 1-Deoxy-6-oxa-(؊)-calystegine B₄Derivatives

The preparation of the 5-deoxy-5-thioureido--gulofur-

anose derivatives 15Ϫ17 was accomplished in six steps from

1-O-acetyl-2,3:4,5-di-O-isopropylidene-α--mannofur-

anose^[31](7) through a reaction sequence that involved: (i)

selective removal of the 5,6-O-acetonide group by treatment

with 50% aqueous acetic acid (Ǟ 8), (ii) protection of the

primary hydroxyl group as the corresponding tri-

phenylmethyl ether (Ǟ 9), (iii) S_N2 displacement of the re-

maining hydroxy group by azide via a trifluoromethanesul-

fonate ester intermediate (Ǟ 10), (iv) hydrolysis of the O-6

trityl group with boron trifluoride diethyl etherate (Ǟ 11),

(v) reduction of the azide group (Ǟ 12), and (vi) a chemose-

Figure 2. 6-oxa-(ϩ)-calystegine B₂derivatives

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Eur. J. Org. Chem. 2004, 1803Ϫ1819

Synthesis of Calystegine B₂, B₃, and B₄Analogues

FULL PAPER

Figure 3. Synthetic strategy for the preparation of 6-oxacalystegines from 5-deoxy-5-(thio)ureidohexofuranoses (I) via the open-chain

aldehyde form (II) and the piperidine intermediate (III)

lective coupling reaction of the generated amine with phe- per-O-protected azide 18 with triphenylphosphane and in

nyl isothiocyanate, 2,3,4,6-tetra-O-acetyl-β--glucopyrano- situ aza-Wittig-type reaction with the corresponding

syl isothiocyanate^[32](13) or methyl 2,3,4-tri-O-acetyl-6-de- isothiocyanate^[35Ϫ37]afforded the carbodiimide adducts

oxy-6-isothiocyanato-α--glucopyranoside^[33](14), respec- 19Ϫ21. Further acid-catalyzed addition of water to the het-

tively (Scheme 1).^[34]

erocumulene group^[38]led to the corresponding 5-deoxy-5-

ureido--gulofuranose derivatives 22Ϫ24 in 69Ϫ94% yield

(Scheme 2).

Full O-deprotection of the thioureas 15Ϫ17 and ureas

22Ϫ24 by deacetylation and treatment with 9:1 trifluoro-

acetic acid-water afforded the target 1-deoxy-6-oxa-(Ϫ)-ca-

lystegine B₄derivatives 25Ϫ27 and 28Ϫ30, respectively

(Scheme 3). The ¹H NMR spectra, recorded in D₂O, exhibit

coupling constant values around the piperidine ring charac-

teristic of trans, gauche, gauche, dispositions between 2-H,

3-H, 4-H, and 5-H, confirming the axial orientation of 4-

4

OH, while the long-range J_H,Hcoupling constant between

2-H and the exo-oriented methylene proton 7b-H (J_4,7b

ϭ

0.6 Hz), in a W arrangement, attests to the rigidity of the

6-oxa-nor-tropane core. The ¹³C NMR spectra show the

typical low-field resonance for the N-thiocarbonyl or N-car-

bonyl group. In the case of the pseudodisaccharide deriva-

tives, the resonance of the corresponding linking carbon

atom (C-1Ј or C-6Ј) experiences a significant high-field shift

relative to the parent monosaccharide, in agreement with

the presence of the (thio)urea bridge.

Synthesis of 1-Deoxy-6-oxa-(؉)-calystegine B₃Derivatives

To implement the above synthetic strategy in order to

access 6-oxa-(ϩ)-calystegine B₃analogues, the preparation

of 5-amino and 5-azido-5-deoxy--altrofuranose derivatives

was required. Their preparation started from the known 3-

O-acetyl-1,2-O-isopropylidene-α--galactofuranose^[39](31)

and paralleled the reaction pathway described above for the

-gulo derivatives. Sequential O-6 tritylation (Ǟ 32) and

Scheme 1. Reagents and conditions: a, 50% AcOH/H₂O, 40 °C, 4 h,

90%; b, TrCl, pyridine, room temp., 36 h, 84%; c, 1. Tf₂O, CH₂Cl₂,

pyridine, Ϫ25 °C, 1 h. 2. NaN₃, DMF, room temp., 18 h, 75%; d,

BF₃·Et₂O, CH₂Cl₂, 0 °C Ǟ room temp., 2 h, 80%; e, H₂, Pd/C,

MeOH, room temp., 2 h, 88%; f, pyridine, room temp.,18 h,

75Ϫ85%

For the preparation of the urea analogues, a different OH Ǟ N₃exchange (Ǟ 33), with inversion of the configu-

synthetic strategy that avoids the use of hazardous isocyan- ration at C-5, followed by detritylation, afforded the pivotal

ate reagents was developed. Staudinger condensation of the azido alcohol 34, which was subsequently deacetylated (Ǟ

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FULL PAPER

Scheme 2. Reagents and conditions: a, Ac₂O/pyridine, 85%; b, TPP, toluene, room temp., 18 h, 41Ϫ86%; c, 1% TFA in 2:1 acetone/water,

room temp., 8 h, 69Ϫ94%

iso(thio)uronium salts, as seen from the ¹³C NMR spectra

of the corresponding reaction mixtures. A similar behavior

has been previously observed in the -idofuranose series.^[29]

After several coevaporations with water and, finally, neu-

tralization of a water solution with Amberlite IRA 68

(OH^Ϫ) ion-exchange resin, the furanose ring rearranged to

give a transient piperidine species that underwent an intra-

molecular glycosylation in situ to afford the target (ϩ)-caly-

stegine B₃analogues 41 and 42, whose structure was con-

firmed by ¹H and ¹³C NMR spectroscopy, MS and elemen-

tal analysis data (Scheme 4).

Synthesis of 1-Deoxy-6-oxa-3-epi-(؉)-calystegine B₂

Derivatives

Scheme 3. Reagents and conditions: a, 1. NaOMe, MeOH. 2. 90%

TFA-water, 0 °C, 15 min. 3. Amberlite IRA 68 (OH^Ϫ), 65Ϫ85%

For the preparation of 6-oxa-(ϩ)-calystegine B₂ana-

logues with the epimeric configuration at C-3, the general

35) and reduced to the corresponding amino alcohol 36 or synthetic strategy proven successful for the C-2 and C-4 epi-

acetylated to the fully O-protected azide 38. Since the natu- mers was examined. Thus, 1,2:5,6-di-O-isopropylidene-α--

ral compound calystegine B₃is a rather poor glycosidase allofuranose^[40](43) was transformed into the 5-amino- and

inhibitor, and in view of the glycosidase inhibition results 5-azido-5-deoxy-β--talofuranose derivatives 47 and 49,

obtained in the 6-oxacalystegine B₂and B₄series (see be- respectively, via 44Ϫ46, by standard protecting-group stra-

low), we limited further transformations in this case to the tegies and inversion of the configuration at C-5 (Scheme 5).

synthesis of the N-(NЈ-phenylthiocarbamoyl) and N-(NЈ- Further coupling with phenyl isothiocyanate afforded the

phenylcarbamoyl) derivatives 41 and 42. Thus, reaction of corresponding phenylthiourea 48 or carbodiimide adduct

36 with phenyl isothiocyanate yielded the corresponding 50, the latter being transformed into the phenylurea 51 by

N,NЈ-disubstituted thiourea 37, while StaudigerϪaza-Wit- nucleophilic addition of water. However, in this particular

tig-type condensation of 38 with triphenylphosphane and case full O-deprotection of 48 or 51 and neutralization of

the same isothiocyanate reagent, followed by acid-catalyzed the reaction mixtures with basic anion-exchange resin did

addition of water to the carbodiimide intermediate 39, pro- not result in the expected furanose Ǟ piperidine rearrange-

vided urea 40. Removal of the O-protecting groups as above ment. Instead, an equilibrium between the -talofuranose

led, initially, to α,β-anomeric mixtures of the corresponding anomers 52 or 54, with a very minor proportion (below

-altrofuranose derivatives, probably as the corresponding 5%) of the bicyclic nor-tropane form, was observed in D₂O

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Synthesis of Calystegine B₂, B₃, and B₄Analogues

FULL PAPER

solutions (¹H NMR spectroscopy). Attempts to trap the bi-

cyclic oxa-nor-tropanes 53 and 55 by provoking the intra-

molecular glycosylation reaction at different pHs failed. It

is likely that the steric hindrance imposed by the 1,3-parallel

disposition between the carbon and oxygen substituents at

the piperidine ring in 53 and 55 overcomes, in this case, the

stabilization due to the anomeric effect at the aminoacetal

center.

Synthesis of 6-Oxa-(؊)-calystegine B₂Derivatives

In order to have a complete view of the contribution of

all oxygen substituents at the nor-tropane ring to the bind-

ing affinity of oxacalystegine analogues for the active site

of glycosidases, the preparation and assaying of a 7-oxa-

(ϩ)-calystegine B₂derivative was also considered. Due to

the pseudosymmetry of the molecule, moving the ami-

noacetal endocyclic oxygen atom from the 6-position to the

7-position in the nor-tropane skeleton leads to the enanti-

omeric 6-oxa-(Ϫ)-calystegine B₂series. Consequently, a syn-

thesis from -idose precursors, matching the strategy pre-

viously developed for the 6-oxa-(ϩ)-calystegine B₂counter-

parts,^[29]was elaborated. Thus, 1,2:4,5-di-O-isopropylidene-

β--glucofuranose^[41]56 was transformed, after inversion of

the configuration at C-5, via 57Ϫ60 following the reaction

sequence already discussed in the previous examples, into

5-amino-5-deoxy-1,2-O-isopropylidene-α--idofuranose 61.

Scheme 4. a, TrCl, pyridine, room temp., 24 h, 74%; b, 1. Tf₂O,

CH₂Cl₂, pyridine, Ϫ25 °C. 2. NaN₃, DMF, 12 h, 60% (global); c,

BF₃·Et₂O, CH₂Cl₂, 0 °C Ǟ room temp., 2 h, 75%; d, NaMeO,

MeOH, 95%; e, H₂, Pd/C, MeOH, room temp., 2 h, quant; f, pyri-

dine, room temp., 18 h, 75%; g, Ac₂O/pyridine, room temp., 83%;

h, TPP, toluene, room temp., 18 h, 45%; i, 1% TFA in 2:1 acetone/

water, room temp., 8 h, 88%; j, 1. NaOMe, MeOH (for 40). 2. 90%

TFA-water, 0 °C, 15 min. 3. Amberlite IRA 68 (OH^Ϫ), 65Ϫ90%

Scheme 5. a, 1. Ac₂O-pyridine, room temp. 2. 40% AcOH/water, 40 °C, 24 h. 3. TrCl, pyridine, room temp., 24 h, 74%; b, 1. Tf₂O, CH₂Cl₂,

pyridine, Ϫ25 °C, 30 min. 2. NaN₃, DMF, room temp. 3.5 h. 3. BF₃·Et₂O, CH₂Cl₂, 0 °C Ǟ room temp., 2 h, 60%; c, NaMeO, MeOH,

92%; d, H₂, Pd/C, MeOH, room temp., 2 h, quant; e, pyridine, room temp., 18 h, 65%; f, Ac₂O/pyridine, room temp., 94%; g, TPP,

toluene, 80 °C, 2.5 h, 71%; h, 1% TFA in acetone/water (2:1), room temp., 8 h, 92%; i, 1. NaOMe, MeOH (for 51). 2. 90% TFA-water, 0

°C, 15 min. 3. Amberlite IRA 68 (OH^Ϫ), 80Ϫ92%

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FULL PAPER

Scheme 6. a, 40% AcOH/water, 40 °C, 4 h, 82%; b, TrCl, pyridine, room temp., 24 h, 74%; c, 1. Tf₂O, CH₂Cl₂, pyridine, Ϫ25 °C, 20 min.

2. NaN₃, DMF, room temp. 3.5 h. 3. BF₃·Et₂O, CH₂Cl₂, 0 °C Ǟ room temp., 3.5 h, 66%; d, NaMeO, MeOH, quant.; e, H₂, Pd/C,

MeOH, room temp., 2 h, quant; f, pyridine, room temp., 18 h, 71%; g, 1. TFA/water, 0 °C, 30 min. 2. Amberlite IRA 68 (OH^Ϫ), 95%

The coupling reaction of 61 with phenyl isothiocyanate af- of the above compounds against trehalase (pig kidney), in-

forded the corresponding thiourea adduct 62 which, by tri- vertase (yeast), α-mannosidase (Jack beans), or amylogluco-

fluoroacetic acid-catalyzed hydrolysis of the acetal group sidase (Aspegillus niger). The 6-oxa-(ϩ)-calystegine-B₂ana-

and neutralization of the reaction mixture, led to the 6-oxa- logues 1 and 2, bearing aromatic substituents at the nitrogen

N-(NЈ-phenylthiocarbamoyl)-(Ϫ)-calystegine B₂derivative atom, are strong and selective competitive inhibitors of

63 having identical spectroscopic properties to the pre- mammalian β-glucosidase/β-galactosidase, with inhibition

viously reported enantiomer 1 (Scheme 6).^[29]

constant (K_i) values in the low micromolar range. Actually,

the N-(NЈ-phenylthiocarbamoyl) derivative 1 (K_iϭ 2.5 µ)

inhibits this enzyme 18-fold more strongly than (ϩ)-calyste-

gine B₂(K_iϭ 45 µ).^[11]The enzyme specificity is also re-

markable: while the natural compound also inhibits almond

β-glucosidase (K_iϭ 1.5 µ) and α-galactosidase (K_iϭ 0.86

µ) simultaneously,^[11]compounds 1 and 2 are very weak

inhibitors of these two enzymes. The inhibition activity is

strongly decreased for N-substituents at the 6-oxa-nor-tro-

pane ring having a hydrophilic nature (3Ϫ6).

Mapping the Structure-Glycosidase Inhibitory Properties

Relationships of 6-Oxacalystegine Analogues

The inhibitory activities of the 6-oxacalystegine (ϩ)-B₂

(1Ϫ6), (Ϫ)-B₄(25Ϫ30), (ϩ)-B₃(41, 42), and (Ϫ)-B₂(63) gly-

comimetics, as well as those of the -talofuranose derivatives

52 and 54 containing small proportions of 3-epi-(ϩ)-calyste-

gine B₂analogues 53 and 55, for α-glucosidase (yeast), β-

glucosidase (almonds) β-glucosidase/β-galactosidase (bovine

liver, cytosolic) and α-galactosidase (green coffee beans), are

The high selectivity and potency observed for the 6-oxa-

summarized in Table 1. No inhibition was detected for any (ϩ)-calystegine B₂derivatives bearing aromatic substituents

Table 1. Comparison of inhibitory activities (K_i, µ) for 6-oxa-(ϩ)-calystegine B₂(1Ϫ6), (Ϫ)-B₄(25Ϫ30), (ϩ)-B₃(41, 42), and (Ϫ)-B₂

(63) derivatives, as well as for -altrofuranose/3-epi-6-oxa-(ϩ)-calystegine B₂equilibrium mixtures (52/53, 54/55)

Compound

α-glucosidase

(yeast)

β-glucosidase

(almonds)

β-glucosidase/β-galactosidase

(bovine liver, cytosolic)

α-galactosidase

(coffee beans)

1

n.i.^[a]

n.i.

138

n.i.

970

1500

n.i.

118

n.i

895

n.i.

207

2.5

30

137

172

n.i.

160

n.i

175

n.i.

149

2

3

148

n.i.

325

1640

n.i.

190

870

161

750

424

4

5

6

25

26

27

28

29

30

41

42

52/53

54/55

63

[a]

Inhibition, when detected, was always of the competitive type; n.i. ϭ no inhibition detected.

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Synthesis of Calystegine B₂, B₃, and B₄Analogues

FULL PAPER

in the inhibition of β-glucosidase/β-galactosidase from bov- bond-acceptor groups at this position and optimizing the

ine liver, an enzyme known to possess a hydrophobic bind- structure of the pseudoaglyconic substituent for optimal in-

ing site and for which aromatic β--glucosides are good teraction with the enzyme may, thus, result in still more

substrates,^[42]supports the idea that the (thio)carbamoyl potent and selective inhibitors. Work in that direction is

segment acts as an aglycon-mimicking group in a 1-azasu- currently under way in our laboratories.

gar inhibition mode. As already observed in the natural

compounds, strong inhibition of β-glucosidase by 6-oxaca-

lystegines is associated with the all-equatorial arrangement

of the triol system at the piperidine ring. Changing the con-

Conclusion

figuration at either C-4 (25Ϫ30) or C-2 (41, 42) results in a

We have described here an efficient synthetic route to a

dramatic increase in the inhibition constant values for β-

new family of sp²-azasugar glycomimetics endowed with

glucosidase/β-galactosidase. It seemed at this point that this

the essential structural features of the calystegines. The re-

configurational arrangement, which resembles that of the

action sequence involves: (i) a coupling reaction of an am-

natural -glucopyranoside substrates, in combination with

ino sugar with an isothiocyanate to give a thiourea adduct

a lipophilic nitrogen substituent, was the main structural

or tandem StaudingerϪaza-Wittig-type coupling reaction

requirement for the biological activity of these glycomimet-

of an azido sugar with triphenylphosphane and an isothi-

ics. The high enzyme selectivity observed is probably a

ocyanate to give a carbodiimide, which is further trans-

consequence of the neutral character of sp²-azasugars as

formed into the corresponding urea, (ii) rearrangement of

compared with classical imino sugars. Actually, the partial

the furanose intermediate through the open-chain aldehyde

positive charge density at the nitrogen regions in pseudoam-

form to give a transient piperidine species, and (iii) intramo-

ide functional groups^[43]probably reflects more closely the

lecular glycosylation reaction, with generation of an ami-

situation at the anomeric region in the transition state, lead-

noacetal functional group, thus closing the bicyclic 6-oxa-

ing to enzymatic glycoside hydrolysis, than a protonated

nor-tropane skeleton. Several hydroxylation profiles are

ammonium group.^[44]

available by judicious choice of the monosaccharide precur-

It must be noticed that, assuming the 1-azasugar model

sor. The glycosidase inhibition studies show a remarkable

for the calystegines, the hydroxylation patterns of the (Ϫ)-

influence of both the arrangement of the oxygen substitu-

B₄and (ϩ)-B₃representatives, which would resemble -

ents on the bicyclic core and the nature of the N-substituent

mannose and -galactose when considering a classical aza-

in the inhibitory properties towards mammalian cytosolic

sugar (1,5-imino sugar) mode of action, do not conform to

β-glucosidase/β-galactosidase. The ensemble of data sug-

the configurational pattern of any common monosacchar-

gests a parallelism between the behavior of 6-oxa-(ϩ)-calys-

ide (i.e. -allose and -idose, respectively). This is in agree-

tegine B₂derivatives and the natural calystegine C₁,

ment with the lack of activity against mannosidases and

strongly supporting a 1-azasugar inhibition mode for the

galactosidases of both the natural compounds and the 6-

polyhydroxy-nor-tropane azasugar family.

oxa analogues reported in this work. In contrast, the un-

natural 3-epi-(ϩ)-B₂hydroxylation profile would match that

of -galactose. Since aromatic β--galactosides are also

Experimental Section

substrates of the cytosolic β-glucosidase/β-galactosidase,

structures such as 53 and 55 would be expected to act as

inhibitors of this enzyme. Although their apparent instabil-

ity has prevented a confirmation of this point, the K_ivalue

obtained for 53, considering that the concentration of the

active species is very low, is significant.

Notwithstanding this, the 6-oxa-(Ϫ)-calystegine B₂de-

rivative 63, which fulfils the above requirements, is more

than two orders of magnitude weaker as an inhibitor of β-

glucosidase/β-galactosidase than its enantiomer 1 (K_iϭ 424

µ), indicating that the endocyclic oxygen atom is also play-

General Remarks: Optical rotations were measured at room tem-

perature in 1-cm or 1-dm tubes. IR spectra were recorded on a FT-

IR instrument. ¹H (¹³C) NMR spectra were recorded at 500 (125.7)

and 300 (75.5) MHz. 1D TOCSY as well as 2D COSY and HMQC

experiments were carried out to assist in signal assignment. In the

FAB-MS spectra, the primary beam consisted of Xe atoms with a

maximum energy of 8 keV. The samples were dissolved in m-nitro-

benzyl alcohol or thioglycerol as the matrices and the positive ions

were separated and accelerated over a potential of 7 keV. NaI was

added as cationizing agent. TLC was performed with E. Merck

ing an active role in enzyme binding for this particular en- precoated TLC plates, silica gel 30F-245, with visualization by UV

light and by charring with 10% H₂SO₄or 0.2% w/v cerium() sul-

fate-5% ammonium molybdate in 2  H₂SO₄. Column chromatog-

raphy was carried out with Silica Gel 60 (E. Merk, 230Ϫ400 mesh).

Fully deprotected compounds were purified by GPC (Sephadex G-

10, MeOH/H₂O, 1:1). Acetylations were effected conventionally

with pyridine/Ac₂O (1:1, 10 mL per 1 g of sample). Deacetylations

were effected by treatment with methanolic NaOMe (0.1 equiv. per

mol of acetate) at room temperature for 1 h, followed by neutraliz-

ation with Amberlite IR 120 (H^ϩ) ion-exchange resin or solid

CO₂. Microanalyses were performed by the Instituto de Investiga-

zyme. This result suggests that 6-oxa-(ϩ)-calystegine B₂gly-

comimetics are rather closer analogues of (ϩ)-calystegine

C₁(K_ifor β-glucosidase/β-galactosidase ϭ 3.6 µ and no

inhibition of α-galactosidase),^[11]bearing an extra hydroxyl

substituent at C-6 as compared to calystegine B₂. Accord-

ing to our data, the extra oxygen at this region probably

acts as a hydrogen-bond acceptor in the active site of the

mammalian cytosolic enzyme and also prevents efficient

binding to α-galactosidase and almond β-glucosidase, lead-

´

ing to higher selectivities. Introducing stronger hydrogen- ciones Quımicas (Sevilla, Spain).

Eur. J. Org. Chem. 2004, 1803Ϫ1819

www.eurjoc.org

 2004 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim

1809

´

M. I. Garcıa-Moreno, C. Ortiz Mellet, J. M. Garcıa Fernandez

FULL PAPER

Materials: 1-Deoxy-6-oxa-N-(thiocarbamoyl and carbamoyl)-(ϩ)-

calystegine B₂derivatives 1Ϫ6 were prepared from 5-deoxy-5-thi-

oureido and ureido--idofuranose precursors as reported.^[29]

1-O-Acetyl-2,3:5,6-di-O-isopropylidene-α--mannofuranose^[31](7),

3-O-acetyl-1,2-O-isopropylidene-α--galactofuranose^[39](31),

1,2:5,6-di-O-isopropylidene-α--allofuranose^[40](43), and 1,2:5,6-

di-O-isopropylidene-β--glucofuranose^[11](56) were obtained from

commercial -mannose, -galactose, -glucose, and -glucose,

respectively. 2,3,4,6-Tetra-O-acetyl-β--glucopyranosyl isothiocy-

anate (13) was synthesized from the corresponding per-O-acetyl

glucopyranosyl bromide by treatment with potassium thiocyanate

and tetra-n-butylammonium hydrogensulfate in acetonitrile, fol-

lowing the procedure of Camarasa et al.^[32]Methyl 2,3,4-tri-O-ace-

tyl-6-deoxy-6-isothiocyanato-α--glucopyranoside (14) was ob-

tained by isothiocyanation of the corresponding 6-amino-6-deoxy-

sugar by thiophosgene, as reported previously.^[33]The glycosidases

α-glucosidase (from yeast), β-glucosidase (from almonds), β-gluco-

sidase/β-galactosidase (from bovine liver, cytosolic), trehalase (from

pig kidney), α-galactosidase (from green coffee beans), α-mannosi-

dase (from jack beans), invertase (from yeast), and amyloglucosid-

ase (from Aspergillus Niger), used in the inhibition studies, as well

as α,αЈ-trehalose, sucrose and the corresponding o- and p-nitrophe-

nyl glycoside substrates were purchased from Sigma Chemical Co.

24.7, 25.9 (CMe₂), 64.7 (C-6), 68.7 (C-5), 79.9 (C-3), 81.0 (C-4),

84.8 (C-2), 86.6 (CPh₃), 100.5 (C-1), 113.1 (CMe₂), 127.0Ϫ143.7

(Ph), 169.2 (CO) ppm. FAB-MS: m/z ϭ 527 (80) [M ϩ Na]^ϩ.

C₃₀H₃₂O₇(504.57): calcd. C 71.41, H 6.39; found C 71.27, H 6.20.

1-O-Acetyl-5-azido-5-deoxy-2,3-O-isopropylidene-6-O-trityl-β-L-

gulofuranose (10): Pyridine (0.72 mL) and trifluoromethanesulfonic

anhydride (1.05 mL, 6.36 mmol) were added to a solution of 9

(2.3 g, 4.59 mmol) in CH₂Cl₂(20 mL) at Ϫ25 °C under N₂. The

reaction mixture was allowed to reach room temperature and, after

stirring for 1 h, the mixture was diluted with CH₂Cl₂(15 mL),

washed with saturated aqueous NaHCO₃(15 mL), dried (MgSO₄),

and concentrated. The resulting crude triflate ester was dissolved

in DMF (18 mL), NaN₃(3.04 g, 32.13 mmol, 7 equiv.) was added

and the reaction mixture was stirred at room temperature for 18 h.

The solvent was removed under reduced pressure and the resulting

residue was dissolved in CH₂Cl₂and washed with water. The or-

ganic extract was dried (MgSO₄) and the solvents evaporated to

give a solid which was purified by column chromatography using

EtOAc/petroleum ether (1:5). Yield: 1.8 g (75%). R_fϭ 0.54 (EtOAc/

petroleum ether, 1:2). [α]²_D²ϭ ϩ27.4 (c ϭ 1.0, CH₂Cl₂). IR (KBr):

1

ν˜_maxϭ 2990, 2101, 1746, 1379, 1235, 1213, 1105 cm^Ϫ1. H NMR

(300 MHz, CDCl₃): δ ϭ 1.15 (s, 3 H, Me), 1.39 (s, 3 H, Me), 2.08

(s, 3 H, MeCO), 3.24 (dd, J_5,6bϭ 4.9, J_6a,6bϭ 9.9 Hz, 1 H, 6b-H),

3.55 (dd, J_5,6aϭ 3.1, J_6a,6bϭ 9.9 Hz, 1 H, 6a-H), 3.84 (ddd, J_4,5

ϭ

1-O-Acetyl-2,3-O-isopropylidene-α-D-mannofuranose (8): 1-O-Ace-

8.9, J_5,6aϭ 3.1, J_5,6bϭ 4.9 Hz, 1 H, 5-H), 4.24 (dd, J_3,4ϭ 3.4,

J_4,5ϭ 8.9 Hz, 1 H, 4-H), 4.32 (dd, J_2,3ϭ 5.8, J_3,4ϭ 3.4 Hz, 1 H,

3-H), 4.59 (d, J_2,3ϭ 5.8 Hz, 1 H, 2-H), 6.15 (s, 1 H, 1-H),

7.48Ϫ7.24 (m, 15 H, 3 Ph) ppm. ¹³C NMR (75.5 MHz, CDCl₃):

δ ϭ 20.9 (MeCO), 24.5, 25.8 (CMe₂), 61.2 (C-5), 62.8 (C-6), 78.8

(C-3), 81.4 (C-4), 85.1 (C-2), 86.9 (CPh₃), 100.5 (C-1), 112.9

(CMe₂), 127.0Ϫ143.3 (Ph), 169.2 (CO) ppm. FAB-MS: m/z ϭ 552

(100) [M ϩ Na]^ϩ. C₃₀H₃₁N₃O₆(529.58): calcd. C 68.04, H 5.90, N

7.94; found C 67.88, H 5.71, N 7.84.

tyl-2,3:5,6-di-O-isopropylidene-α--mannofuranose (7) (2.0 g,

6.62 mmol) was suspended in 50% aqueous AcOH (6 mL) and

heated at 40 °C for 4 h. The resulting solution was concentrated

and coevaporated several times with water and toluene to eliminate

traces of the acid. The residue was purified by column chromatog-

raphy using EtOAc/petroleum ether (2:1) Ǟ EtOAc as an eluent.

Yield: 1.55 g (90%). R_fϭ 0.38 (EtOAc/petroleum ether, 3:1). [α]²_D²

ϩ55.0 (c ϭ 1.0, CH₂Cl₂). IR (KBr): ν˜_maxϭ 3459, 2988, 1746, 1408,

1379, 1235, 1213, 1094 cm^Ϫ^{1 1}H NMR (500 MHz, CDCl₃): δ ϭ

ϭ

.

1.34 (s, 3 H, Me), 1.47 (s, 3 H, Me), 2.05 (s, 3 H, MeCO), 2.87 (br. 1-O-Acetyl-5-azido-5-deoxy-2,3-O-isopropylidene-β-

s, 1 H, OH), 2.88 (br. s, 1 H, OH), 3.71 (dd, J_5,6bϭ 4.9, J_6a,6b(11): BF₃·Et₂O (391 µL) and MeOH (1 mL) were added to a solu-

11.3 Hz, 1 H, 6b-H), 3.85 (d, J_6a,6bϭ 11.3 Hz, 1 H, 6a-H), 4.00 tion of the tritylated azido derivative 10 (1.5 g, 2.8 mmol) in

(dd, J_4,5ϭ 8.2, J_5,6bϭ 4.9 Hz, 1 H, 5-H), 4.09 (dd, J_3,4ϭ 3.8, CH₂Cl₂(19 mL), at 0 °C under Ar. The reaction mixture was al-

J_4,5ϭ 8.2 Hz, 1 H, 4-H), 4.69 (d, J_2,3ϭ 5.9 Hz, 1 H, 2-H), 4.91 lowed to reach room temperature and stirred for 2 h, then washed

(dd, J_2,3ϭ 5.9, J_3,4ϭ 3.8 Hz, 1 H, 3-H), 6.15 (s, 1 H, 1-H). ¹³C with saturated aqueous NaHCO₃(2 ϫ 10 mL), dried (MgSO₄), and

L-gulofuranose

ϭ

NMR (125.7 MHz, CDCl₃): δ ϭ 20.9 (MeCO), 24.7, 25.9 (CMe₂),

concentrated. The resulting residue was purified by column chro-

64.0 (C-6), 70.0 (C-5), 79.8 (C-4), 81.3 (C-3), 84.8 (C-2), 100.6 (C-

matography (EtOAc/petroleum ether, 1:4 Ǟ 1:1). Yield: 644 mg

1), 113.3 (CMe₂), 169.2 (CO) ppm. FAB-MS: m/z ϭ 285 (100) [M (80%). R_fϭ 0.24 (EtOAc/petroleum ether, 1:2). [α]²_D²ϭ ϩ44.0 (c ϭ

ϩ Na]^ϩ, 263 (40) [M ϩ H]^ϩ. C₁₁H₁₈O₇(262.26): calcd. C 50.38, H 1.0, CH₂Cl₂). IR (KBr): ν˜_maxϭ 3503, 2990, 2104, 1748, 1379, 1231,

6.92; found C 50.15, H 6.62.

1

1100 cm^Ϫ1. H NMR (300 MHz, CDCl₃): δ ϭ 1.32 (s, 3 H, Me),

1.49 (s, 3 H, Me), 2.08 (s, 3 H, MeCO), 3.75 (dd, J_5,6bϭ 5.8,

1-O-Acetyl-2,3-O-isopropylidene-6-O-trityl-α-D-mannofuranose (9):

J

_6a,6bϭ 12.4 Hz, 1 H, 6b-H), 3.87 (dd, J_5,6aϭ 3.1, J_6a,6bϭ 12.4 Hz,

Trityl chloride (1.9 g, 6.8 mmol, 1.5 equiv.) was added to a solution

of 8 (1.25 g, 4.59 mmol) in pyridine (8 mL) and the solution was

stirred at room temperature for 36 h. The reaction mixture was

poured into ice-water (80 mL) and the resulting solid was dissolved

in toluene (40 mL) and washed with iced aqueous 10% AcOH

(10 mL), saturated aqueous NaHCO₃(10 mL), dried (MgSO₄), and

the solvents evaporated under reduced pressure. The residue was

purified by column chromatography eluting with EtOAc/petroleum

ether (1:3). Yield: 1.94 g (84%). R_fϭ 0.58 (EtOAc/petroleum ether,

1:1). [α]²_D²ϭ ϩ25.8 (c ϭ 1.0, CH₂Cl₂). IR (KBr): ν˜_maxϭ 3445,

1 H, 6a-H), 3.88 (m, 1 H, 5-H), 4.22 (dd, J_3,4ϭ 3.5, J_4,5ϭ 8.5 Hz,

1 H, 4-H), 4.71 (d, J_2,3ϭ 5.8 Hz, 1 H, 2-H), 4.79 (dd, J_2,3ϭ 5.8,

J_3,4ϭ 3.5 Hz, 1 H, 3-H), 6.20 (s, 1 H, 1-H) ppm. ¹³C NMR

(75.5 MHz, CDCl₃): δ ϭ 20.9 (MeCO), 24.7, 25.9 (CMe₂), 61.9 (C-

5), 63.1 (C-6), 78.9 (C-3), 82.0 (C-4), 85.2 (C-2), 100.2 (C-1), 113.3

(CMe₂), 169.4 (CO) ppm. FAB-MS: m/z ϭ 272 (30) [M Ϫ Me]^ϩ.

C₁₁H₁₇N₃O₆(287.27): calcd. C 45.99, H 5.96, N 14.63; found C

45.95, H, 5.95, N 14.53.

1-O-Acetyl-5-amino-5-deoxy-2,3-O-isopropylidene-β-L-gulofuranose

(12): A solution of 11 (474 mg, 1.65 mmol) in MeOH (30 mL) was

hydrogenated at atmospheric pressure for 2 h using 10% Pd/C

(163.3 mg) as catalyst. The suspension was filtered through Celite

and concentrated to give 13 as a hygroscopic solid which was used

in the next step without further purification.

2988, 1748, 1402, 1379, 1262, 1211, 1094 cm^{Ϫ1 1}H NMR

.

(300 MHz, CDCl₃): δ ϭ 1.36 (s, 3 H, Me), 1.49 (s, 3 H, Me), 2.04

(s, 3 H, MeCO), 2.82 (d, J_5,OHϭ 6.2 Hz, 1 H, OH), 3.44Ϫ3.36 (m,

2 H, 6a-H, 6b-H), 4.11 (m, 1 H, 5-H), 4.20 (dd, J_3,4ϭ 3.4, J_4,5

ϭ

7.8 Hz, 1 H, 4-H), 4.71 (d, J_2,3ϭ 5.9 Hz, 1 H, 2-H), 4.94 (dd, J_2,3ϭ

5.9, J_3,4ϭ 3.4 Hz, 1 H, 3-H), 6.18 (s, 1 H, 1-H), 7.18Ϫ7.48 (m, 15

H, 3 Ph) ppm. ¹³C NMR (75.5 MHz, CDCl₃): δ ϭ 20.9 (MeCO),

L-Gulofuranose-derived Thioureas 15؊17. General Procedure: The

corresponding isothiocyanate (phenyl isothiocyanate, 13 or 14;

1810

 2004 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim

www.eurjoc.org

Eur. J. Org. Chem. 2004, 1803Ϫ1819

Synthesis of Calystegine B₂, B₃, and B₄Analogues

FULL PAPER

0.5 mmol) was added to a solution of amine 12 (0.5 mmol) in pyri-

dine (5 mL). The resulting mixture was stirred at room temperature

for 18 h, then coevaporated several times with toluene under vac-

uum. The resulting residue was purified by column chromatogra-

phy using EtOAc/petroleum ether (1:1 Ǟ 3:1) to afford the thioure-

ido derivatives 15Ϫ17.

H, 2Ј-H), 4.88 (t, J_3Ј,4Јϭ J_4Ј,5Јϭ 9.6 Hz, 1 H, 4Ј-H), 4.90 (d, J_1Ј,2Јϭ

3.7 Hz, 1 H, 1Ј-H), 5.42 (t, J_2Ј,3Јϭ J_3Ј,4Јϭ 9.6 Hz, 1 H, 3Ј-H), 6.12

(s, 1 H, 1-H), 6.57 (bd, J_NЈH,6aЈ5.0 Hz, 1 H, NЈH), 6.80 (br. s, 1 H,

NH) ppm. ¹³C NMR (125.7 MHz, CDCl₃, 313 K): δ ϭ 20.4Ϫ20.8

(MeCO), 24.7, 26.0 (CMe₂), 44.9 (C-6Ј), 55.4 (OMe), 55.5 (C-5),

61.7 (C-6), 68.3 (C-5Ј), 69.6 (C-4Ј), 70.1 (C-3Ј), 71.1 (C-2Ј), 79.2

(C-3), 80.9 (C-4), 85.3 (C-2), 96.9 (C-1Ј), 100.3 (C-1), 113.4 (CMe₂),

169.1Ϫ170.1 (CO), 183.9 (CS) ppm. FAB-MS: m/z ϭ 645 (100) [M

ϩ Na]^ϩ, 623 (45) [M ϩ H]^ϩ. C₂₅H₃₈O₁₄N₂S (622.64): calcd. C

48.22, H 6.15, N 4.50; found C 47.87, H 5.93, N 4.30.

1-O-Acetyl-5-deoxy-2,3-O-isopropylidene-5-(NЈ-phenylthioureido)-

β-L-gulofuranose (15): Yield: 158 mg, (80%). R_fϭ 0.60 (EtOAc/

petroleum ether, 4:1). [α]²_D²ϭ ϩ78.0 (c ϭ 1.0, CH₂Cl₂). UV

(CH₂Cl₂) 267 nm (ε_m 26.3). IR (KBr): ν˜_maxϭ 3339, 2961, 1740,

1

1651, 1537, 1260, 1094, 1013 cm^Ϫ1. H NMR (500 MHz, CDCl₃):

1,6-Di-O-acetyl-5-azido-5-deoxy-2,3-O-isopropylidene-β-L-

δ ϭ 1.29 (s, 3 H, Me), 1.41 (s, 3 H, Me), 2.06 (s, 3 H, MeCO), 3.87

(dd, J_5,6bϭ 4.8, J_6a,6bϭ 11.5 Hz, 1 H, 6b-H), 3.93 (dd, J_5,6aϭ 3.8,

J_6a,6bϭ 11.5 Hz, 1 H, 6a-H), 4.45 (dd, J_3,4ϭ 3.5, J_4,5ϭ 6.8 Hz, 1

H, 4-H), 4.69 (d, J_2,3ϭ 5.8 Hz, 1 H, 2-H), 4.77 (dd, J_2,3ϭ 5.8,

gulofuranose (18): Conventional acetylation of 11 (100 mg,

0.35 mmol) and purification of the crude reaction mixture by col-

umn chromatography (EtOAc/petroleum ether, 1:3 Ǟ 1:2) gave 18.

Yield: 98 mg (85%). R_fϭ 0.47 (EtOAc/petroleum ether, 1:2). [α]²_D²

ϭ

J_3,4ϭ 3.5 Hz, 1 H, 3-H), 4.87 (ddd, J_4,5ϭ 6.8, J_5,6aϭ 3.8, J_5,6b

ϭ

ϩ55.9 (c ϭ 0.85, CH₂Cl₂). IR (KBr): ν˜_maxϭ 2989, 2104, 1748,

1

1377, 1231, 1094 cm^Ϫ1. H NMR (300 MHz, CDCl₃): δ ϭ 1.29 (s,

4.8 Hz, 1 H, 5-H), 6.13 (s, 1 H, 1-H), 6.80 (br. s, 1 H, NH),

7.40Ϫ7.20 (m, 5 H, Ph), 8.50 (br. s, 1 H, NЈH) ppm. ¹³C NMR

(125.7 MHz, CDCl₃): δ ϭ 21.0 (MeCO), 24.5, 25.8 (CMe₂), 55.4

(C-5), 61.4 (C-6), 79.1 (C-3, C-4), 85.1 (C-2), 100.0 (C-1), 113.5

(CMe₂), 124.3Ϫ130.0 (Ph), 169.3 (CO), 180.5 (CS) ppm. FAB-MS:

m/z ϭ 419 (100) [M ϩ Na]^ϩ, 397 (40) [M ϩ H]^ϩ. C₁₈H₂₄N₂O₆S

(396.46): calcd. C 54.53, H 6.10, N 7.07; found C 54.65, H 6.02,

N 6.92.

3 H, Me), 1.47 (s, 3 H, Me), 2.06 (s, 3 H, Me), 2.11 (s, 3 H, MeCO),

3.96 (ddd, J_5,6aϭ 3.7, J_5,6bϭ 5.7, J_4,5ϭ 9.8 Hz, 1 H, 5-H), 4.09

(dd, J_3,4ϭ 3.1, J_4,5ϭ 9.8 Hz, 1 H, 4-H), 4.24 (dd, J_6a,6bϭ 12.0,

J_5,6bϭ 5.7 Hz, 1 H, 6b-H), 4.30 (dd, J_5,6aϭ 3.7, J_6a,6bϭ 12.0 Hz,

1 H, 6a-H), 4.70 (d, J_2,3ϭ 5.8 Hz, 1 H, 2-H), 4.73 (dd, J_2,3ϭ 5.8,

J_3,4ϭ 3.1 Hz, 1 H, 3-H), 6.17 (s, 1 H, 1-H) ppm. ¹³C NMR

(75.5 MHz, CDCl₃): δ ϭ 20.6, 20.8 (MeCO), 24.6, 25.8 (CMe₂),

59.8 (C-5), 63.1 (C-6), 78.8 (C-3), 81.5 (C-4), 85.2 (C-2), 100.1 (C-

1), 113.4 (CMe₂), 169.0, 170.4 (CO) ppm. FAB-MS: m/z ϭ 352 (70)

[M ϩ Na]^ϩ. C₁₃H₁₉N₃O₇(329.31): calcd. C 47.41, H 5.82, N 12.76;

found C 47.44, H 5.95, N 12.76.

1-O-Acetyl-5-deoxy-2,3-O-isopropylidene-5-[NЈ-(2,3,4,6-tetra-O-

acetyl-β-D-glucopyranosyl)thioureido]-β-L-gulofuranose (16): Yield:

275 mg (85%). R_fϭ 0.47 (EtOAc/petroleum ether, 4:1). [α]²_D²ϭ ϩ16

(c ϭ 1.0, CH₂Cl₂). UV (CH₂Cl₂) 257 nm (ε_m 19.1). IR (KBr):

ν˜_maxϭ 3308, 2961, 1750, 1651, 1514, 1260, 1094, 1034 cm^{Ϫ1 1}H

.

L-Gulofuranose-Derived Carbodiimides 19؊21. General Procedure:

NMR (500 MHz, CDCl₃, 313 K): δ ϭ 1.33 (s, 3 H, Me), 1.51 (s, 3

H, Me), 2.00 (s, 3 H, MeCO), 2.01 (s, 3 H, MeCO), 2.03 (s, 3 H,

MeCO), 2.05 (s, 3 H, MeCO), 2.06 (s, 3 H, MeCO), 3.81 (dd,

J_5,6bϭ 4.5, J_6a,6bϭ 11.6 Hz, 1 H, 6b-H), 3.84 (ddd, J_5Ј,6bЈϭ 2.5,

J_5Ј,6aЈϭ 4.4, J_4Ј,5Јϭ 9.5 Hz, 1 H, 5Ј-H), 3.88 (dd, J_5,6aϭ 3.7,

A solution of furanose 18 (0.2 g, 0.6 mmol) in toluene (4 mL) was

stirred at room temperature under N₂for 30 min. Then, the corre-

sponding isothiocyanate (0.73 mmol, 1.2 equiv.) and a solution of

TPP (0.67 mmol, 1.1 equiv.) in toluene (2 mL) were added success-

ively. The resulting solution was stirred overnight, concentrated un-

der vacuum and the resulting residue was purified by column chro-

matography using the eluent indicated in each case.

J_6a,6bϭ 11.6 Hz, 1 H, 6a-H), 4.16 (dd, J_6aЈ,6bЈϭ 12.5, J_5Ј,6bЈ

2.5 Hz, 1 H, 6bЈ-H), 4.33 (dd, J_5Ј,6aЈϭ 4.4, J_6aЈ,6bЈϭ 12.5 Hz, 1 H,

6aЈ-H), 4.39 (m, 1 H, 4-H), 4.68 (m, 1 H, 5-H), 4.69 (d, J_2,3

5.8 Hz, 1 H, 2-H), 4.80 (dd, J_2,3ϭ 5.8, J_3,4ϭ 3.5 Hz, 1 H, 3-H),

5.01 (t, J_1Ј,2Јϭ J_2Ј,3Јϭ 9.5 Hz, 1 H, 2Ј-H), 5.11 (t, J_3Ј,4Јϭ J_4Ј,5Ј

ϭ

1,6-Di-O-acetyl-5-deoxy-2,3-O-isopropylidene-5-(NЈ-phenyl-

carbodiimido)-β-L-gulofuranose (19): Eluent: EtOAc/petroleum

ϭ

ether (1:5 Ǟ 1:1). Yield: 136 mg (56%). R_fϭ 0.25 (EtOAc/petro-

9.5 Hz, 1 H, 4Ј-H), 5.33 (t, J_2Ј,3Јϭ J_3Ј,4Јϭ 9.5 Hz, 1 H, 3Ј-H), 5.63

(t, J_1Ј,NЈHϭ J_1Ј,2Јϭ 9.5 Hz, 1 H, 1Ј-H), 6.16 (s, 1 H, 1-H), 6.80

(br. s, 1 H, NЈH), 7.20Ϫ7.40 (m, 5 H, Ph), 8.30 (br. s, 1 H, NH)

ppm. ¹³C NMR (75.5 MHz, CDCl₃, 313 K): δ ϭ 21.7Ϫ22.0 (5

MeCO), 24.6, 25.9 (CMe₂), 55.1 (C-5), 61.5 (C-6, C-6Ј), 68.4 (C-

4Ј), 70.8 (C-2Ј), 73.6 (C-5Ј), 73.8 (C-3Ј), 79.2 (C-3, C-4), 83.1 (C-

1Ј), 85.3 (C-2), 100.2 (C-1), 113.6 (CMe₂), 169.2, 169.4, 169.7,

170.5, 171.1 (CO), 183.9 (CS) ppm. FAB-MS: m/z ϭ 673 (80) [M

ϩ Na]^ϩ, 651 (20) [M ϩ H]^ϩ. C₂₆H₃₈N₂O₁₅S (650.65): calcd. C

47.99, H 5.89, N 4.31; found C 48.11, H 5.69, N 4.29.

leum ether, 1:5). [α]²_D²ϭ ϩ74.5 (c ϭ 1.0, CH₂Cl₂). IR (KBr): ν˜_maxϭ

2988, 2133, 1744, 1539, 1505, 1379, 1225, 1094 cm^{Ϫ1 1}H NMR

.

(500 MHz, CDCl₃): δ ϭ 1.30 (s, 3 H, Me), 1.50 (s, 3 H, Me), 1.99

(s, 3 H, MeCO), 2.06 (s, 3 H, MeCO), 4.12 (ddd, J_5,6bϭ 3.6, J_5,6aϭ

4.8, J_4,5ϭ 8.9 Hz, 1 H, 5-H), 4.18 (dd, J_3,4ϭ 3.3, J_4,5ϭ 8.9 Hz, 1

H, 4-H), 4.32 (dd, J_5,6bϭ 3.6, J_6a,6bϭ 11.7 Hz, 1 H, 6b-H), 4.35

(dd, J_5,6aϭ 4.8, J_6a,6bϭ 11.7 Hz, 1 H, 6a-H), 4.73 (d, J_2,3ϭ 5.8 Hz,

1 H, 2-H), 4.78 (dd, J_2,3ϭ 5.8, J_3,4ϭ 3.3 Hz, 1 H, 3-H), 6.22 (s, 1

H, 1-H), 7.10Ϫ7.30 (m, 5 H, Ph) ppm. ¹³C NMR (75.5 MHz,

CDCl₃): δ ϭ 20.6, 20.8, (MeCO), 24.6, 25.9 (CMe₂), 56.4 (C-5),

63.8 (C-6), 78.6 (C-3), 82.0 (C-4), 85.4 (C-2), 99.9 (C-1), 113.4

(CMe₂), 123.9Ϫ138.1 (Ph), 139.2 (NCN), 168.9, 170.5 (CO) ppm.

FAB-MS: m/z ϭ 427 (60) [M ϩ Na]^ϩ. C₂₀H₂₄N₂O₇(404.41): calcd.

C 59.40, H 5.94, N 6.93; found C 59.16, H 6.03, N 6.92.

1-O-Acetyl-5-deoxy-2,3-O-isopropylidene-5-[NЈ-(methyl 2,3,4-tri-O-

acetyl-α-

D-glucopyranosid-6-yl)thioureido]-β-L-gulofuranose

(17):

Yield: 233 mg (75%). R_fϭ 0.38 (EtOAc/petroleum ether, 3:1).

[α]²_D²ϭ ϩ133 (c ϭ 1.0, CH₂Cl₂). UV (CH₂Cl₂) 250 nm (ε_m 12.5).

IR (KBr): ν˜_maxϭ 3366, 2984, 1750, 1678, 1516, 1254, 1092, 1040

cm^Ϫ1. ¹H NMR (500 MHz, CDCl₃, 323 K): δ ϭ 1.30 (s, 3 H, Me),

1,6-Di-O-acetyl-5-deoxy-2,3-O-isopropylidene-5-[NЈ-(2,3,4,6-tetra-

1.40 (s, 3 H, Me), 1.95 (s, 3 H, MeCO), 1.97 (s, 3 H, MeCO), 2.00 O-acetyl-β-

(s, 3 H, MeCO), 2.02 (s, 3 H, MeCO), 3.73 (m, 1 H, 5Ј-H), 3.75 Eluent: EtOAc/petroleum ether (1:3 Ǟ 2:1). Yield: 340 mg (86%).

(m, 1 H, 6bЈ-H), 3.84 (dd, J_5,6bϭ 3.5, J_6a,6bϭ 11.5 Hz, 1 H, 6b- R_fϭ 0.29 (EtOAc/petroleum ether, 1:1). [α]²_D²ϭ ϩ60.1 (c ϭ 0.8

H), 3.89 (dd, J_5,6aϭ 4.0, J_6a,6bϭ 11.5 Hz, 1 H, 6a-H), 3.93 (m, 1 CH₂Cl₂). IR (KBr): ν˜_maxϭ 2988, 2141, 1750, 1626, 1377, 1227,

H, 6aЈ-H), 4.36 (dd, J_3,4ϭ 3.5, J_4,5ϭ 7.5 Hz, 1 H, 4-H), 4.50 (m, 1094 cm^Ϫ1. H NMR (500 MHz, CDCl₃): δ ϭ 1.28 (s, 3 H, Me),

D-glucopyranosyl)carbodiimido]-β-L-gulofuranose (20):

1

1 H, 5-H), 4.66 (d, J_2,3ϭ 5.5 Hz, 1 H, 2-H), 4.78 (dd, J_2,3ϭ 5.5,

J_3,4ϭ 3.5 Hz, 1 H, 3-H), 4.81 (dd, J_2Ј,3Јϭ 9.6, J_1Ј,2Јϭ 3.7 Hz, 1

1.45 (s, 3 H, Me), 1.98 (s, 3 H, MeCO), 1.99 (s, 3 H, MeCO), 2.01

(s, 3 H, MeCO), 2.02 (s, 3 H, MeCO), 2.08 (s, 3 H, MeCO), 2.12 (s,

Eur. J. Org. Chem. 2004, 1803Ϫ1819

www.eurjoc.org

 2004 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim

1811

´

M. I. Garcıa-Moreno, C. Ortiz Mellet, J. M. Garcıa Fernandez

FULL PAPER

3 H, MeCO), 3.83 (ddd, J_5Ј,6bЈϭ 2.5, J_5Ј,6aЈϭ 4.7, J_4Ј,5Јϭ 9.4 Hz, 1

(MeCO), 24.3, 25.7 (CMe₂), 48.9 (C-5), 64.3 (C-6), 79.4 (C-3), 80.5

H, 5Ј-H), 3.99 (dd, J_3,4ϭ 3.3, J_4,5ϭ 9.3 Hz, 1 H, 4-H), 4.10 (ddd, (C-4), 84.8 (C-2), 100.0 (C-1), 113.3 (CMe₂), 120.1Ϫ138.6 (Ph),

J

_4,5ϭ 9.3, J_5,6bϭ 2.6, J_5,6aϭ 5.2 Hz, 1 H, 5-H), 4.11 (dd, J_5Ј,6bЈ

ϭ

155.1 (CO urea), 169.4, 171.1 (CO ester) ppm. FAB-MS: m/z ϭ

445 (100) [M ϩ Na]^ϩ. C₂₀H₂₆N₂O₈(422.43): calcd. C 56.87, H

6.16, N 6.63; found C 56.56, H 6.24, N 6.62.

2.5, J_6aЈ,6bЈϭ 12.4 Hz, 1 H, 6bЈ-H), 4.12 (dd, J_5,6bϭ 2.6, J_6a,6b

ϭ

11.8 Hz, 1 H, 6b-H), 4.17 (dd, J_5,6aϭ 5.2, J_6a,6bϭ 11.8 Hz, 1 H,

6a-H), 4.22 (dd, J_5Ј,6aЈϭ 4.7, J_6aЈ,6bЈϭ 12.4 Hz, 1 H, 6aЈ-H), 4.71

(dd, J_2,3ϭ 5.8, J_3,4ϭ 3.3 Hz, 1 H, 3-H), 4.74 (d, J_2,3ϭ 5.8 Hz, 1

H, 2-H), 4.96 (dd, J_1Ј,2Јϭ 8.7, J_2Ј,3Јϭ 9.4 Hz, 1 H, 2Ј-H), 4.97 (d,

J_1Ј,2Јϭ 8.7 Hz, 1 H, 1Ј-H), 5.08 (t, J_3Ј,4Јϭ J_4Ј,5Јϭ 9.4 Hz, 1 H, 4Ј-

H), 5.25 (t, J_2Ј,3Јϭ J_3Ј,4Јϭ 9.4 Hz, 1 H, 3Ј-H), 6.13 (s, 1 H, 1Ј-H)

ppm. ¹³C NMR (125.7 MHz, CDCl₃): δ ϭ 20.6Ϫ20.9 (MeCO),

24.7, 26.0 (CMe₂), 55.9 (C-5), 61.9 (C-6Ј), 63.6 (C-6), 68.1 (C-3Ј),

72.9 (C-2Ј), 73.1 (C-4Ј), 73.4 (C-5Ј), 78.4 (C-3), 81.5 (C-4), 84.1 (C-

1Ј), 86.3 (C-2), 99.7 (C-1), 113.6 (CMe₂), 139.6 (NCN),

169.2Ϫ170.5 (CO) ppm. FAB-MS: m/z ϭ 681 (30) [M ϩ Na]^ϩ.

C₂₈H₃₈N₂O₁₆(658.61): calcd. C 51.06, H 5.82, N 4.25; found C

51.08, H 5.84, N 4.25.

1,6-Di-O-acetyl-5-deoxy-2,3-O-isopropylidene-5-[NЈ-(2,3,4,6-tetra-

O-acetyl-β-D-glucopyranosyl)ureido]-β-L-gulofuranose (23): Eluent:

EtOAc/petroleum ether (1:1) Ǟ EtOAc. Yield: 382 mg (94%). R_fϭ

0.45 (EtOAc/petroleum ether, 3:1). [α]²_D²ϭ ϩ24.4 (c ϭ 1.0 CH₂Cl₂).

IR (KBr): ν˜_maxϭ 3397, 2959, 1748, 1547, 1377, 1229, 1094 cm^Ϫ1

.

¹H NMR (500 MHz, CDCl₃, 313 K): δ ϭ 1.28 (s, 3 H, Me), 1.45

(s, 3 H, Me), 1.99 (s, 3 H, MeCO), 2.00 (s, 3 H, MeCO), 2.02 (s, 3

H, MeCO), 2.03 (s, 3 H, MeCO), 2.05 (s, 3 H, MeCO), 2.06 (s, 3

H, MeCO), 3.79 (ddd, J_5Ј,6bЈϭ 2.0, J_5Ј,6aЈϭ 4.2, J_4Ј,5Јϭ 9.5 Hz, 1

H, 5Ј-H), 4.06 (dd, J_6aЈ,6bЈϭ 12.5, J_5Ј,6bЈϭ 2.0 Hz, 1 H, 6bЈ-H),

4.10 (m, 1 H, 4-H), 4.12 (dd, J_5,6bϭ 2.6, J_6a,6bϭ 12.5 Hz, 1 H,

6b-H), 4.31 (dd, J_5Ј,6aЈϭ 4.2, J_6aЈ,6bЈϭ 12.5 Hz, 1 H, 6aЈ-H), 4.43

(dd, J_5,6aϭ 4.2, J_6a,6bϭ 12.5 Hz, 1 H, 6a-H), 4.44 (m, 1 H, 5-H),

4.66 (d, J_2,3ϭ 5.9 Hz, 1 H, 2-H), 4.74 (dd, J_2,3ϭ 5.9, J_3,4ϭ 3.7 Hz,

1 H, 3-H), 4.89 (t, J_1Ј,2Јϭ J_2Ј,3Јϭ 9.5 Hz, 1 H, 2Ј-H), 5.05 (t,

J_3Ј,4Јϭ J_4Ј,5Јϭ 9.5 Hz, 1 H, 4Ј-H), 5.11 (d, J_NH,5ϭ 8.0 Hz, 1 H,

1,6-Di-O-acetyl-5-deoxy-2,3-O-isopropylidene-5-[NЈ-(methyl 2,3,4-

tri-O-acetyl-6-deoxy-β-

gulofuranose (21): Eluent: EtOAc/petroleum ether (1:1). Yield:

155 mg (41%). R_fϭ 0.37 (EtOAc/petroleum ether, 1:1). [α]²_D²

ϩ109.5 (c ϭ 1.0, CH₂Cl₂). IR (KBr): ν˜_maxϭ 2959, 2137, 1750,

1626, 1373, 1225, 1094 cm^{Ϫ1 1}H NMR (500 MHz, CDCl₃): δ ϭ J_3Ј,4Јϭ 9.5 Hz, 1 H, 3Ј-H), 5.41 (d, J_NЈH,1Јϭ 9.5 Hz, 1 H, NЈH),

1.26 (s, 3 H, Me), 1.44 (s, 3 H, Me), 1.96 (s, 3 H, MeCO), 1.98 (s, 6.11 (s, 1 H, 1-H) ppm. ¹³C NMR (125.7 MHz, CDCl₃): δ ϭ

D-glucopyranosid-6-yl)carbodiimido]-β-L-

ϭ

NH), 5.14 (t, J_NЈH,1Јϭ J_1Ј,2Јϭ 9.5 Hz, 1 H, 1Ј-H), 5.27 (t, J_2Ј,3Ј

ϭ

.

3 H, MeCO), 2.00 (s, 3 H, MeCO), 2.06 (s, 3 H, MeCO), 2.10 (s,

3 H, MeCO), 3.38 (s, 3 H, OMe), 3.36 (dd, J_5Ј,6bЈϭ 5.8, J_6aЈ,6bЈ

13.7 Hz, 1 H, 6bЈ-H), 3.40 (dd, J_5Ј,6aЈϭ 3.3, J_6aЈ,6bЈϭ 13.7 Hz, 1

20.4Ϫ20.9 (MeCO), 24.5, 25.8 (CMe₂), 48.8 (C-5), 61.6 (C-6Ј), 64.2

(C-6), 68.2 (C-4Ј), 70.4 (C-2Ј), 72.9 (C-3Ј), 73.0 (C-5Ј), 79.2 (C-3),

80.2 (C-1Ј), 80.5 (C-4), 84.9 (C-2), 100.0 (C-1), 113.4 (CMe₂), 155.6

ϭ

H, 6aЈ-H), 3.81 (ddd, J_4Ј,5Јϭ 9.5, J_5Ј,6aЈϭ 3.3, J_5Ј,6bЈϭ 5.8 Hz, 1 (CO urea), 169.1Ϫ171.1 (CO ester) ppm. FAB-MS: m/z ϭ 699 (100)

H, 5Ј-H), 3.99 (ddd, J_5,6bϭ 3.3, J_5,6aϭ 5.2, J_4,5ϭ 5.8 Hz, 1 H, 5-

[M ϩ Na]^ϩ. C₂₈H₄₀N₂O₁₇(676.62): calcd. C 49.70, H 5.96, N 4.14;

H), 4.17 (dd, J_5,6bϭ 3.3, J_6a,6bϭ 11.5 Hz, 1 H, 6b-H), 4.21 (dd, found C 49.45, H 5.82, N 4.00.

_5,6aϭ 5.2, J_6a,6bϭ 11.5 Hz, 1 H, 6a-H), 4.68 (dd, J_3,4ϭ 3.1, J_4,5ϭ

J

1,6-Di-O-acetyl-5-deoxy-2,3-O-isopropylidene-5-[NЈ-(methyl 2,3,4-

tri-O-acetyl-6-deoxy-β- -glucopyranosid-6-yl)ureido]-β- -gulo

5.8 Hz, 1 H, 4-H), 4.69 (d, J_2,3ϭ 5.9 Hz, 1 H, 2-H), 4.70 (dd, J_2,3ϭ

5.9, J_3,4ϭ 3.1 Hz, 1 H, 3-H), 4.83 (dd, J_1Ј,2Јϭ 3.6, J_2Ј,3Јϭ 10.1 Hz,

1 H, 2Ј-H), 4.90 (d, J_1Ј,2Јϭ 3.6 Hz, 1 H, 1Ј-H), 4.99 (t, J_3Ј,4Ј

D

L

furanose (24): Eluent: EtOAc/petroleum ether (3:1) Ǟ EtOAc.

Yield: 269 mg (69%). R_fϭ 0.49 (EtOAc). [α]²_D²ϭ ϩ106.9 (c ϭ 1.0,

CH₂Cl₂). IR (KBr): ν˜_maxϭ 3412, 2986, 1748, 1649, 1551, 1375,

ϭ

J_4Ј,5Јϭ 9.5 Hz, 1 H, 4Ј-H), 5.42 (dd, J_2Ј,3Јϭ 10.1, J_3Ј,4Јϭ 9.5 Hz,

1 H, 3Ј-H), 6.11 (s, 1 H, 1-H) ppm. ¹³C NMR (125.7 MHz, CDCl₃):

δ ϭ 20.6Ϫ20.8 (5 MeCO), 24.8, 26.0 (CMe₂), 46.7 (C-6Ј), 55.5

(OMe), 55.8 (C-5), 64.2 (C-6), 68.1 (C-5Ј), 69.8 (C-4Ј), 70.2 (C-3Ј),

70.9 (C-2Ј), 78.7 (C-3), 82.1 (C-4), 85.5 (C-2), 96.7 (C-1Ј), 100.1

(C-1), 113.4 (CMe₂), 140.6 (NCN), 170.7Ϫ169.3 (CO) ppm. FAB-

MS: m/z ϭ 631 (80) [M ϩ H]^ϩ. C₂₇H₃₈N₂O₁₅(630.60): calcd. C

51.42, H 6.07, N 4.44; found C 51.30, H 5.72, N 4.33.

1

1227, 1092 cm^Ϫ1. H NMR (500 MHz, CDCl₃): δ ϭ 1.23 (s, 3 H,

Me), 1.45 (s, 3 H, Me), 1.95 (s, 3 H, MeCO), 1.99 (s, 3 H, MeCO),

2.01 (s, 3 H, MeCO), 2.04 (s, 3 H, MeCO), 2.09 (s, 3 H, MeCO),

3.26 (dd, J_5Ј,6bЈϭ 5.9, J_6aЈ,6bЈϭ 14.5 Hz, 1 H, 6bЈ-H), 3.45 (s, 3 H,

OMe), 3.46 (dd, J_5Ј,6aЈϭ 2.4, J_6aЈ,6bЈϭ 14.5 Hz, 1 H, 6aЈ-H), 3.83

(ddd, J_4Ј,5Јϭ 10.1, J_5Ј,6aЈϭ 2.4, J_5Ј,6bЈϭ 5.9 Hz, 1 H, 5Ј-H), 4.13

(dd, J_3,4ϭ 3.6, J_4,5ϭ 6.9 Hz, 1 H, 4-H), 4.16 (dd, J_5,6bϭ 4.2,

J_6a,6bϭ 11.5 Hz, 1 H, 6b-H), 4.32 (ddd, J_4,5ϭ 6.9, J_5,6aϭ 4.8,

J_5,6bϭ 4.2 Hz, 1 H, 5-H), 4.43 (dd, J_5,6aϭ 4.8, J_6a,6bϭ 11.5 Hz,

1 H, 6a-H), 4.64 (d, J_2,3ϭ 5.9 Hz, 1 H, 2-H), 4.73 (dd, J_2,3ϭ 5.9,

J_3,4ϭ 3.6 Hz, 1 H, 3-H), 4.81 (dd, J_1Ј,2Јϭ 3.7, J_2Ј,3Јϭ 10.2 Hz, 1

H, 2Ј-H), 4.87 (dd, J_3Ј,4Јϭ 9.5, J_4Ј,5Јϭ 10.1 Hz, 1 H, 4Ј-H), 4.88

(d, J_1Ј,2Јϭ 3.7 Hz, 1 H, 1Ј-H), 4.95 (m, 2 H, NH, NЈH), 5.43 (dd,

J_2Ј,3Јϭ 10.2, J_3Ј,4Јϭ 9.5 Hz, 1 H, 3Ј-H), 6.12 (s, 1 H, 1-H) ppm.

¹³C NMR (125.7 MHz, CDCl₃): δ ϭ 20.7Ϫ21.0 (MeCO), 24.6, 26.0

(CMe₂), 40.3 (C-6Ј), 49.3 (C-5), 55.4 (OMe), 64.5 (C-6), 68.3 (C-

5Ј), 69.5 (C-4Ј), 70.0 (C-3Ј), 71.0 (C-2Ј), 79.4 (C-3), 80.9 (C-4), 84.9

(C-2), 96.5 (C-1Ј), 100.2 (C-1), 113.4 (CMe₂), 157.4 (CO urea),

169.4Ϫ171.2 (CO ester) ppm. FAB-MS: m/z ϭ 671 (100) [M ϩ

Na]^ϩ. C₂₇H₄₀N₂O₁₆(648.61): calcd. C 49.99, H 6.22, N 4.32; found

C 50.29, H 6.26, N 4.27.

L

-Gulofuranose-Derived Ureas 22؊24. General Procedure: TFA

(0.1 mL) was added to a solution of the corresponding carbodiim-

ido derivative 19Ϫ21 (0.6 mmol) in acetone/water (2:1, 13.5 mL).

The reaction mixture was stirred at room temperature for 8 h, then

the solvents were evaporated under vacuum and the resulting resi-

due was purified by column chromatography using the eluent indi-

cated in each case.

1,6-Di-O-acetyl-5-deoxy-2,3-O-isopropylidene-5-(NЈ-phenylureido)-

β-L-gulofuranose (22): Eluent: EtOAc/petroleum ether (1:1 Ǟ 2:1).

Yield: 204 mg (81%). R_fϭ 0.56 (EtOAc/petroleum ether, 3:1).

[α]²_D²ϭ ϩ21.5 (c ϭ 1.0, CH₂Cl₂). IR (KBr): ν˜_maxϭ 3391, 3364,

1742, 1601, 1559, 1524, 1379, 1227, 1094 cm^{Ϫ1 1}H NMR

.

(500 MHz, CDCl₃): δ ϭ 1.30 (s, 3 H, Me), 1.40 (s, 3 H, Me), 2.05

(s, 3 H, MeCO), 2.06 (s, 3 H, MeCO), 4.21 (dd, J_5,6bϭ 6.2, J_6a,6bϭ

13.5 Hz, 1 H, 6b-H), 4.23 (dd, J_3,4ϭ 3.6, J_4,5ϭ 6.2 Hz, 1 H, 4-H), N-Thiocarbamoyl- and N-Carbamoyl-6-oxa-(؊)-calystegine B₄De-

4.47 (td, J_5,6aϭ 5.2, J_4,5ϭ J_5,6bϭ 6.2 Hz, 1 H, 5-H), 4.48 (dd,

J_5,6aϭ 5.2, J_6a,6bϭ 13.5 Hz, 1 H, 6a-H), 4.68 (d, J_2,3ϭ 5.9 Hz, 1

rivatives 25؊27 and 28؊30. General Procedure: Thioureas 15Ϫ17

and ureas 22Ϫ24 (0.5 mmol) were conventionally deacetylated by

H, 2-H), 4.79 (dd, J_2,3ϭ 5.9, J_3,4ϭ 3.6 Hz, 1 H, 3-H), 5.37 (br. s, treatment with methanolic NaOMe (1 , 0.1 equiv. per mol of acet-

1 H, NH), 6.16 (s, 1 H, 1-H), 6.98 (br. s, 1 H, NЈH), 7.26Ϫ7.33 (m, ate). The resulting product was dissolved in a mixture of TFA/H₂O

5 H, Ph) ppm. ¹³C NMR (125.7 MHz, CDCl₃): δ ϭ 20.8, 20.9 (9:1, 3 mL) and stirred at 0 °C for 15 min until disappearance of

1812

 2004 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim

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Eur. J. Org. Chem. 2004, 1803Ϫ1819

Synthesis of Calystegine B₂, B₃, and B₄Analogues

FULL PAPER

the starting material (TLC). The solvent was removed under vac-

(1S,2R,3S,4S,5R)-2,3,4-Trihydroxy-6-oxa-N-(NЈ-phenylcarbamoyl)-

uum, the residue was coevaporated several times with water and nor-tropane (28): Eluent: CH₂Cl₂/MeOH (7:1 Ǟ 3:1). Yield: 122 mg

finally the aqueous solution was neutralized by treatment with Am-

(87%). R_fϭ 0.44 (EtOAc/EtOH/H₂O, 45:5:3). [α]²_D²ϭ ϩ13.5 (c ϭ

berlite IRA 68 (OH^Ϫ) ion-exchange resin and freeze dried. The 1.0, MeOH). ¹H NMR (500 MHz, D₂O): δ ϭ 3.53 (ddd, J_2,7b

ϭ

resulting residue was purified by column chromatography with the

eluent indicated in each case. The corresponding 6-oxa-(Ϫ)-calyste-

0.6, J_1,7bϭ 4.3, J_7a,7bϭ 8.4 Hz, 1 H, 7b-H), 3.62 (dd, J_3,4ϭ 4.8,

J_2,3ϭ 9.3 Hz, 1 H, 3-H), 3.81 (dd, J_1,2ϭ 4.3, J_2,3ϭ 9.3 Hz, 1 H,

gine B₄derivatives 25Ϫ27 and 28Ϫ30 were isolated as white foams 2-H), 3.91 (dd, J_3,4ϭ 4.8, J_4,5ϭ 3.7 Hz, 1 H, 4-H), 4.49 (t, J_1,2

ϭ

after freeze-drying of water solutions.

J_1,7bϭ 4.3 Hz, 1 H, 1-H), 5.70 (d, J_4,5ϭ 3.7 Hz, 1 H, 5-H),

7.20Ϫ7.40 (m, 5 H, Ph) ppm. ¹³C NMR (125.7 MHz, D₂O): δ ϭ

56.6 (C-1), 63.6 (C-7), 69.6 (C-4), 70.1 (C-3), 70.2 (C-2), 85.1 (C-

5), 122.7Ϫ137.2 (Ph), 156.8 (CO urea) ppm. FAB-MS: m/z ϭ 281

(70) [M ϩ H]^ϩ. C₁₃H₁₆N₂O₅(280.28): calcd. C 55.71, H 5.75, N

9.99; found C 55.60, H 5.60, N 9.84.

(1S,2R,3S,4S,5R)-2,3,4-Trihydroxy-6-oxa-N-(NЈ-phenylthiocarba-

moyl)-nor-tropane (25): Eluent: CH₂Cl₂/MeOH (20:1 Ǟ 9:1). Yield:

104 mg (70%). R_fϭ 0.51 (CH₂Cl₂/MeOH, 4:1). [α]²_D²ϭ ϩ38.4 (c ϭ

1.0, H₂O). UV (MeOH): 250 nm (ε_m 20.9). H NMR (500 MHz,

D₂O, 313 K): δ ϭ 3.95 (dd, J_1,7bϭ 4.5, J_7a,7bϭ 8.5 Hz, 1 H, 7b-

1

H), 3.99 (dd, J_3,4ϭ 4.8, J_2,3ϭ 9.2 Hz, 1 H, 3-H), 4.14 (dd, J_1,2

4.5 Hz, 1 H, 2-H), 4.26 (d, J_7a,7bϭ 8.5 Hz, 1 H, 7a-H), 4.30 (dd, hydroxy-6-oxa-nor-tropane (29): Yield: 137 mg (75%). Eluent:

J_3,4ϭ 4.8, J_4,5ϭ 3.7 Hz, 1 H, 4-H), 5.26 (t, J_1,2ϭ J_1,7bϭ 4.5 Hz, MeCN/H₂O (7:1 Ǟ 4:1). R_fϭ 0.38 (MeCN/H₂O/NH₄OH, 6:3:1).

1 H, 1-H), 6.35 (d, J_4,5ϭ 3.7 Hz, 1 H, 5-H), 7.50Ϫ7.60 (m, 5 H, [α]²_D²ϭ Ϫ11.0 (c ϭ 1.0, H₂O). ¹H NMR (500 MHz, D₂O): δ ϭ 3.38

Ph) ppm. ¹³C NMR (125.7 MHz, D₂O, 313 K): δ ϭ 61.7 (C-1), (dd, J_3Ј,4Јϭ 9.1, J_4Ј,5Јϭ 9.5 Hz, 1 H, 4Ј-H), 3.42 (t, J_1Ј,2Јϭ J_2Ј,3Ј

ϭ

(1S,2R,3S,4S,5R)-N-[NЈ-(β-D-Glucopyranosyl)carbamoyl]-2,3,4-tri-

ϭ

66.6 (C-7), 72.2 (C-2), 72.3 (C-3), 72.8 (C-4), 89.1 (C-5),

9.1 Hz, 1 H, 2Ј-H), 3.45 (ddd, J_5Ј,6aЈϭ 2.2, J_5Ј,6bЈϭ 5.4 Hz, 1 H,

5Ј-H), 3.50 (t, J_2Ј,3Јϭ J_3Ј,4Јϭ 9.1 Hz, 1 H, 3Ј-H), 3.58 (dd, J_1,7b

129.6Ϫ141.5 (Ph), 182.7 (CS) ppm. FAB-MS: m/z ϭ 297 (100) [M

ϭ

ϩ H]^ϩ. C₁₃H₁₆N₂O₄S (296.34): calcd. C 52.69, H 5.44, N 9.45; 4.3, J_7a,7bϭ 8.5 Hz, 1 H, 7b-H), 3.67 (dd, J_3,4ϭ 4.8, J_2,3ϭ 9.2 Hz,

found C 52.65, H 5.45, N 9.44.

1 H, 3-H), 3.68 (dd, J_5Ј,6bЈϭ 5.4, J_6aЈ,6bЈϭ 12.4 Hz, 1 H, 6bЈ-H),

3.83 (dd, J_5Ј,6aЈϭ 2.2, J_6aЈ,6bЈϭ 12.4 Hz, 1 H, 6aЈ-H), 3.84 (dd,

J_1,2ϭ 4.3, J_2,3ϭ 9.2 Hz, 1 H, 2-H), 3.96 (d, J_7a,7bϭ 8.5 Hz, 1 H,

7a-H), 3.97 (dd, J_3,4ϭ 4.8, J_4,5ϭ 3.7 Hz, 1 H, 4-H), 4.51 (t, 1 H,

(1S,2R,3S,4S,5R)-N-[NЈ-(β- -Glucopyranosyl)thiocarbamoyl]-2,3,4-

D

trihydroxy-6-oxa-nor-tropane (26): Eluent: MeCN/H₂O (7:1). Yield:

124 mg (65%). R_fϭ 0.52 (MeCN/H₂O/NH₄OH, 6:3:1). [α]²_D²

Ϫ23.7 (c ϭ 0.97, MeOH). UV (MeOH): 241 nm (ε_m 19.1). ¹H

NMR (500 MHz, D₂O, 313 K): δ ϭ 3.44 (dd, J_1Ј,2Јϭ 6.5, J_2Ј,3Ј

9.1 Hz, 1 H, 2Ј-H), 3.53 (m, 1 H, 5Ј-H), 3.55 (t, J_4Ј,5Јϭ J_3Ј,4Ј

9.1 Hz, 1 H, 4Ј-H), 3.57 (t, J_2Ј,3Јϭ J_3Ј,4Јϭ 9.1 Hz, 1 H, 3Ј-H), 3.74

(dd, J_5Ј,6bЈϭ 5.2, J_6aЈ,6bЈϭ 12.5 Hz, 1 H, 6bЈ-H), 3.77 (dd, J_1,7b

4.3, J_7a,7bϭ 8.5 Hz, 1 H, 7b-H), 3.81 (dd, J_3,4ϭ 4.8, J_2,3ϭ 9.2 Hz,

1 H, 3-H), 3.87 (dd, J_5Ј,6bЈϭ 2.1, J_6aЈ,6bЈϭ 12.5 Hz, 1 H, 6aЈ-H),

ϭ

1-H), 4.87 (d, J_1,2ϭ J_1,7bϭ 4.3 Hz, 1 H, 1Ј-H), 5.75 (d, J_4,5

ϭ

3.7 Hz, 1 H, 5-H) ppm. ¹³C NMR (125.7 MHz, D₂O): δ ϭ 57.5

(C-1), 61.7 (C-6Ј), 64.9 (C-7), 70.4 (C-4Ј), 70.7 (C-4), 71.2 (C-3, C-

2), 72.7 (C-2Ј), 77.6 (C-3Ј), 78.5 (C-5Ј), 82.5 (C-1Ј), 86.4 (C-5),

158.9 (CO urea) ppm. FAB-MS: m/z ϭ 389 (100) [M ϩ Na]^ϩ.

C₁₃H₂₂N₂O₁₀(366.32): calcd. C 42.68, H 6.05, N 7.65; found C

42.92, H 6.22, N 7.67.

ϭ

3.93 (dd, J_1,2ϭ 4.3, J_2,3ϭ 9.2 Hz, 1 H, 2-H), 4.08 (d, J_7a,7b

ϭ

(1S,2R,3S,4S,5R)-2,3,4-Trihydroxy-N-[NЈ-(methyl 6-deoxy-α-

D-glu-

8.5 Hz, 1 H, 7a-H), 4.11 (dd, J_3,4ϭ 4.8, J_4,5ϭ 3.6 Hz, 1 H, 4-H),

copyranosid-6-yl)carbamoyl]-6-oxa-nor-tropane (30): Eluent:

5.10 (t, J_1,2ϭ J_1,7bϭ 4.3 Hz, 1 H, 1-H), 5.66 (d, J_1Ј,2Јϭ 6.5 Hz, 1 MeCN/H₂O (7:1 Ǟ 4:1). Yield: 162 mg (85%). R_fϭ 0.51 (MeCN/

H, 1Ј-H), 6.24 (d, J_4,5ϭ 3.6 Hz, 1 H, 5-H) ppm. ¹³C NMR

(75.5 MHz, D₂O, 313 K): δ ϭ 58.9 (C-1), 60.6 (C-6Ј), 64.1 (C-7),

69.3 (C-4Ј), 69.4 (C-4), 70.1 (C-2), 70.6 (C-3), 71.9 (C-2Ј), 76.6 (C-

H₂O/NH₄OH, 6:3:1). [α]²_D²ϭ ϩ62 (c ϭ 1.0, H₂O). ¹H NMR

(500 MHz, D₂O): δ ϭ 3.30 (t, J_3Ј,4Јϭ J_4Ј,5Јϭ 9.5 Hz, 1 H, 4Ј-H),

3.40 (s, 3 H, OMe), 3.42 (dd, J_5Ј,6bЈϭ 7.8, J_6aЈ,6bЈϭ 14.5 Hz, 1 H,

3Ј), 77.6 (C-5Ј), 84.9 (C-1Ј), 86.3 (C-5), 184 (CS) ppm. FAB-MS: 6bЈ-H), 3.55 (dd, J_1,7bϭ 4.2, J_7a,7bϭ 8.5 Hz, 1 H, 7b-H), 3.57 (dd,

m/z ϭ 405 (30) [M ϩ Na]^ϩ. C₁₃H₂₂N₂O₉S (280.28): calcd. C 40.83,

H 5.80, N 7.33; found C 40.68, H 5.86, N 7.24.

J_1Ј,2Јϭ 3.8, J_2Ј,3Јϭ 9.9 Hz, 1 H, 2Ј-H), 3.63 (ddd, J_4Ј,5Јϭ 9.5,

J_5Ј,6aЈϭ 2.7, J_5Ј,6bЈϭ 7.8 Hz, 1 H, 5Ј-H), 3.64 (dd, J_5Ј,6aЈϭ 2.7,

J_6aЈ,6bЈϭ 14.5 Hz, 1 H, 6aЈ-H), 3.65 (dd, J_2Ј,3Јϭ 9.9, J_3Ј,4Јϭ 9.5 Hz,

1 H, 3Ј-H), 3.71 (dd, J_3,4ϭ 4.9, J_2,3ϭ 9.2 Hz, 1 H, 3-H), 3.87 (dd,

J_1,2ϭ 4.2, J_2,3ϭ 9.2 Hz, 1 H, 2-H), 4.00 (d, J_7a,7bϭ 8.5 Hz, 1 H,

7a-H), 4.02 (dd, J_3,4ϭ 4.9, J_4,5ϭ 3.7 Hz, 1 H, 4-H), 4.52 (t, J_1,2ϭ

J_1,7bϭ 4.2 Hz, 1 H, 1-H), 4.79 (d, J_1Ј,2Јϭ 3.8 Hz, 1 H, 1Ј-H), 5.73

(d, J_4,5ϭ 3.7 Hz, 1 H, 5-H) ppm. ¹³C NMR (125.7 MHz, D₂O):

δ ϭ 41.5 (C-6Ј), 55.3 (OMe), 56.9 (C-1), 63.8 (C-7), 69.9 (C-5Ј),

70.6 (C-2), 70.7 (C-3), 70.8 (C-4), 71.8 (C-2Ј, C-4Ј), 73.4 (C-3Ј),

86.5 (C-5), 99.6 (C-1Ј), 159.3 (CO urea) ppm. FAB-MS: m/z ϭ 403

(100) [M ϩ Na]^ϩ. C₁₄H₂₄N₂O₁₀(380.35): calcd. C 44.21, H 6.36,

N 7.36; found C 44.26, H 6.37, N 7.36.

(1S,2R,3S,4S,5R)-2,3,4-Trihydroxy-N-[NЈ-(methyl α-D-glucopyrano-

sid-6-yl)thiocarbamoyl]-6-oxa-nor-tropane (27): Eluent: EtOAc/

EtOH (20:1 Ǟ 3:1). Yield: 141 mg (71%). R_fϭ 0.54 (EtOAc/EtOH,

1:1). [α]²_D²ϭ ϩ83.7 (c ϭ 1.0, H₂O). UV (MeOH): 249 nm (ε_m

12.9). ¹H NMR (500 MHz, D₂O, 313 K): δ ϭ 3.30 (t, J_4Ј,5Ј

J_3Ј,4Јϭ 9.5 Hz, 1 H, 4Ј-H), 3.37 (s, 3 H, OMe), 3.41 (dd, J_1Ј,2Ј

ϭ

4.0, J_2Ј,3Јϭ 9.5 Hz, 1 H, 2Ј-H), 3.65 (t, J_2Ј,3Јϭ J_3Ј,4Јϭ 9.5 Hz, 1

H, 3Ј-H), 3.69 (ddd, J_2,7bϭ 1.0, J_1,7bϭ 4.5, J_7a,7bϭ 8.5 Hz, 1 H,

7b-H), 3.79 (dd, J_3,4ϭ 5.0, J_2,3ϭ 9.0 Hz, 1 H, 3-H), 3.80 (dd,

J_5Ј,6bЈϭ 8.0, J_6aЈ,6bЈϭ 13.0 Hz, 1 H, 6bЈ-H), 3.83 (ddd, J_4Ј,5Јϭ 9.5,

J_5Ј,6aЈϭ 2.5, J_5Ј,6bЈϭ 8.0 Hz, 1 H, 5Ј-H), 3.88 (ddd, J_1,2ϭ 4.3,

J_2,3ϭ 9.0, J_2,7bϭ 1.0 Hz, 1 H, 2-H), 4.06 (d, J_7a,7bϭ 8.5 Hz, 1 H, 3-O-Acetyl-1,2-O-isopropylidene-6-O-trityl-α-

7a-H), 4.12 (dd, J_4,5ϭ 3.5, J_3,4ϭ 5.0 Hz, 1 H, 4-H), 4.13 (dd, (32): Trityl chloride (1.9 g, 6.8 mmol, 1.5 equiv.) was added to a

J_5Ј,6aЈϭ 2.5, J_6aЈ,6bЈϭ 13.0 Hz, 1 H, 6aЈ-H), 4.78 (d, J_1Ј,2Јϭ 4.0 Hz, solution of 3-O-acetyl-1,2-O-isopropylidene-α--galactofuranose

D-galactofuranose

1 H, 1Ј-H), 5.06 (t, J_1,2ϭ J_1,7bϭ 4.3 Hz, 1 H, 1-H), 6.09 (d, J_4,5ϭ

(31) (1.25 g, 4.59 mmol) in pyridine (8 mL),. The reaction mixture

3.5 Hz, 1 H, 5-H) ppm. ¹³C NMR (125.7 MHz, D₂O, 313 K): δ ϭ was stirred at room temperature for 24 h, then poured into ice-

46.4 (C-6Ј), 55.1 (OMe), 58.9 (C-1), 63.8 (C-7), 69.8 (C-2), 69.9 (C- water (80 mL) and decanted. A solution of the solid in toluene

5Ј), 70.3 (C-3), 70.5 (C-4), 71.5 (C-2Ј), 71.8 (C-4Ј), 73.1 (C-3Ј), 86.4 (20 mL) was washed with iced aqueous 10% acetic acid (10 mL),

(C-5), 99.3 (C-1Ј), 180.1 (CS) ppm. FAB-MS: m/z ϭ 419 (80) [M

ϩ Na]^ϩ, 397 (75) [M ϩ H]^ϩ. C₁₄H₂₄N₂O₉S (396.41): calcd. C 42.42, (MgSO₄), and concentrated. The resulting residue was purified by

H 6.10, N 7.07; found C 42.23, H 6.06, N 7.06. column chromatography using EtOAc/petroleum ether (1:3). Yield:

aqueous saturated NaHCO₃(10 mL), the organic phase was dried

Eur. J. Org. Chem. 2004, 1803Ϫ1819

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 2004 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim

1813

´

M. I. Garcıa-Moreno, C. Ortiz Mellet, J. M. Garcıa Fernandez

FULL PAPER

1.7 g (74%). R_fϭ 0.67 (EtOAc/petroleum ether, 1:1). [α]²_D²ϭ Ϫ3.0

5-Azido-5-deoxy-1,2-O-isopropylidene-β-L-altrofuranose (35): Con-

(c ϭ 1.0, CH₂Cl₂). IR (KBr): ν˜_maxϭ 3503, 3059, 2988, 1746, 1377,

ventional deacetylation of 34 (0.3 g, 1.07 mmol) gave 33. Yield:

1

1229, 1092 cm^Ϫ1. H NMR (300 MHz, CDCl₃): δ ϭ 1.32 (s, 3 H, 250 mg (95%). R_fϭ 0.43 (EtOAc/petroleum ether, 2:1). [α]²_D²

ϭ

Me), 1.61 (s, 3 H, Me), 2.05 (s, 3 H, MeCO), 3.23 (dd, J_5,6bϭ 5.6, Ϫ11.0 (c ϭ 1.0, MeOH). IR (KBr): ν˜_maxϭ 3445, 2988, 2101, 1382,

1

J_6a,6bϭ 9.8 Hz, 1 H, 6b-H), 3.28 (dd, J_5,6aϭ 5.4, J_6a,6bϭ 9.8 Hz, 1092 cm^Ϫ1. H NMR (300 MHz, CD₃OD): δ ϭ 1.29 (s, 3 H, Me),

1 H, 6a-H), 3.98 (ddd, J_4,5ϭ 6.7, J_5,6aϭ 5.4, J_5,6bϭ 5.6 Hz, 1 H, 1.49 (s, 3 H, Me), 3.63 (dd, J_5,6bϭ 6.9, J_6a,6bϭ 11.1 Hz, 1 H, 6b-

5-H), 4.23 (dd, J_3,4ϭ 2.4, J_4,5ϭ 6.7 Hz, 1 H, 4-H), 4.59 (d, J_1,2

4.1 Hz, 1 H, 2-H), 5.12 (d, J_3,4ϭ 2.4 Hz, 1 H, 3-H), 5.91 (d, J_1,2ϭ

ϭ

H), 3.67 (ddd, J_4,5ϭ 9.4, J_5,6aϭ 2.1, J_5,6bϭ 6.9 Hz, 1 H, 5-H),

3.79 (dd, J_3,4ϭ 1.4, J_4,5ϭ 9.4 Hz, 1 H, 4-H), 3.95 (dd, J_5,6aϭ 2.1,

4.1 Hz, 1 H, 1-H), 7.23Ϫ7.46 (m, 15 H, 3 Ph) ppm. ¹³C NMR J_6a,6bϭ 11.1 Hz, 1 H, 6a-H), 4.28 (d, J_3,4ϭ 1.4 Hz, 1 H, 3-H),

(75.5 MHz, CDCl₃): δ ϭ 20.6 (MeCO), 25.9, 26.5 (CMe₂), 64.8 (C- 4.52 (d, J_1,2ϭ 3.8 Hz, 1 H, 2-H), 5.88 (d, J_1,2ϭ 3.8 Hz, 1 H, 1-H)

6), 69.6 (C-5), 77.9 (C-3), 84.9 (C-2), 86.1 (C-4), 87.2 (CPh₃), 105.3 ppm. ¹³C NMR (75.5 MHz, CD₃OD): δ ϭ 25.9, 27.0 (CMe₂), 63.2

(C-1), 112.8 (CMe₂), 126.9Ϫ143.7 (Ph), 170.0 (CO) ppm. FAB-MS: (C-5), 65.6 (C-6), 76.9 (C-3), 87.5 (C-2), 88.0 (C-4), 107.9 (C-1),

m/z ϭ 527 (100) [M ϩ Na]^ϩ. C₃₀H₃₂O₇(504.57): calcd. C 71.41, H 113.5 (CMe₂) ppm. FAB-MS: m/z ϭ 268 (50) [M ϩ Na]^ϩ.

6.39; found C 71.60, H 6.41.

C₉H₁₅N₃O₅(245.23): calcd. C 44.08, H 6.16, N 17.13; found C

44.07, H 6.03, N 17.12.

3-O-Acetyl-5-azido-5-deoxy-1,2-O-isopropylidene-6-O-trityl-β-L-

5-Amino-5-deoxy-1,2-O-isopropylidene-β-L-altrofuranose (36):

A

altrofuranose (33): Pyridine (0.4 mL) and trifluoromethanesulfonic

anhydride (0.48 mL, 2.9 mmol) were added to a solution of 32

(1.0 g, 2.0 mmol) in CH₂Cl₂(9 mL) at Ϫ25 °C under N₂. The reac-

tion mixture was allowed to reach room temperature and stirred for

20 min, then diluted with CH₂Cl₂(10 mL), washed with saturated

aqueous NaHCO₃(8 mL), dried (MgSO₄), and concentrated. The

resulting crude triflate ester was dissolved in DMF (8 mL), NaN₃

(1.40 g, 14 mmol, 7 equiv.) was added and the reaction mixture was

stirred at room temperature for 12 h. The solvent was eliminated

under reduced pressure and the resulting residue was purified by

column chromatography using EtOAc/petroleum ether (1:4). Yield:

solution of 35 (1.07 mmol) in MeOH (10 mL) was hydrogenated at

atmospheric pressure for 2 h using 10% Pd/C (107 mg) as catalyst.

The suspension was filtered through Celite and concentrated to

give 34 as a hygroscopic solid which was used in the next step with-

out further purification.

5-Deoxy-1,2-O-isopropylidene-5-(NЈ-phenylthioureido)-β-L-altro-

furanose (37): Phenyl isothiocyanate was added to a solution of the

crude amine 36 (1.08 mmol) in pyridine (1 mL). The reaction mix-

ture was stirred at room temperature for 12 h, then coevaporated

several times with toluene under vacuum. The resulting residue was

purified by column chromatography using CH₂Cl₂/MeOH, 30:1.

0.63 g (60%). R_fϭ 0.65 (EtOAc/petroleum ether, 1:2). [α]²_D²

ϭ

Yield: 287 mg (75%). R_fϭ 0.58 (CH₂Cl₂/MeOH, 20:1). [α]²_D²

ϭ

Ϫ17.0 (c ϭ 1.0, CH₂Cl₂). IR (KBr): ν˜_maxϭ 2959, 2099, 1746, 1348,

ϩ27.0 (c ϭ 1.0, CH₂Cl₂). UV (CH₂Cl₂): 269 nm (ε_m 12.7). IR

1

1227, 1094 cm^Ϫ1. H NMR (500 MHz, CDCl₃): δ ϭ 1.31 (s, 3 H,

1

(KBr): ν˜_maxϭ 3362, 3065, 2990, 1537, 1379, 1092 cm^Ϫ1. H NMR

Me), 1.51 (s, 3 H, Me), 2.07 (s, 3 H, MeCO), 3.30 (dd, J_5,6bϭ 7.3,

J_6a,6bϭ 9.8 Hz, 1 H, 6b-H), 3.56 (dd, J_5,6aϭ 2.8, J_6a,6bϭ 9.8 Hz,

1 H, 6a-H), 3.89 (ddd, J_4,5ϭ 9.9, J_5,6aϭ 2.8, J_5,6bϭ 7.3 Hz, 1 H,

(300 MHz, CDCl₃, 313 K): δ ϭ 1.31 (s, 3 H, Me), 1.52 (s, 3 H,

Me), 3.80 (bd, J_6a,6bϭ 11.4 Hz, 1 H, 6b-H), 3.99 (dd, J_5,6aϭ 2.6,

J_6a,6bϭ 11.4 Hz, 1 H, 6a-H), 4.01 (dd, J_3,4ϭ 3.5, J_4,5ϭ 7.5 Hz, 1

H, 4-H), 4.52 (d, J_3,4ϭ 3.5 Hz, 1 H, 3-H), 4.58 (d, J_1,2ϭ 3.8 Hz,

1 H, 2-H), 4.78 (m, 1 H, 5-H), 5.85 (d, J_1,2ϭ 3.8 Hz, 1 H, 1-H),

6.95 (br. s, 1 H, NH), 7.20Ϫ7.40 (m, 5 H, Ph), 8.40 (br. s, 1 H,

NЈH) ppm. ¹³C NMR (75.5 MHz, CDCl₃, 313 K): δ ϭ 26.2, 26.9,

(CMe₂), 56.9 (C-5), 61.4 (C-6), 76.2 (C-3), 86.2 (C-4), 87.3 (C-2),

105.1 (C-1), 113.4 (CMe₂), 124.4, 126.6, 129.6 (Ph), 180.6 (CS)

ppm. FAB-MS: m/z ϭ 377 (100) [M ϩ Na]^ϩ. C₁₆H₂₂N₂O₅S

(354.42): calcd. C 54.22, H 6.25, N 7.90; found C 54.05, H 6.38,

N 7.81.

5-H), 3.98 (dd, J_3,4ϭ 1.4, J_4,5ϭ 9.9 Hz, 1 H, 4-H), 4.53 (d, J_1,2

ϭ

3.8 Hz, 1 H, 2-H), 5.64 (d, J_3,4ϭ 1.4 Hz, 1 H, 3-H), 5.85 (d, J_1,2ϭ

3.8 Hz, 1 H, 1-H), 7.24Ϫ7.49 (m, 15 H, 3 Ph) ppm. ¹³C NMR

(125.7 MHz, CDCl₃): δ ϭ 20.7 (MeCO), 25.7, 26.6 (CMe₂), 62.3

(C-5), 63.5 (C-6), 77.6 (C-3), 83.4 (C-2), 84.4 (C-4), 87.2 (CPh₃),

105.9 (C-1), 112.8 (CMe₂), 127.0Ϫ143.6 (Ph), 169.5 (CO) ppm.

FAB-MS: m/z ϭ 552 (100) [M ϩ Na]^ϩ. C₃₀H₃₁N₃O₆(529.58):

calcd. C 68.04, H 5.90, N 7.94; found C 67.96, H 5.73, N 7.91.

3-O-Acetyl-5-azido-5-deoxy-1,2-O-isopropylidene-β-L-altrofuranose

3,6-Di-O-acetyl-5-azido-5-deoxy-1,2-O-isopropylidene-β-L-altro-

(34): BF₃·Et₂O (391 mL) and MeOH (1 mL) were added to a solu-

tion of 33 (1.5 g, 2.8 mmol) in CH₂Cl₂(18 mL) at 0 °C under Ar.

The reaction mixture was allowed to reach room temperature and

stirred for 2 h, then washed with saturated aqueous NaHCO₃(2 ϫ

10 mL), dried (MgSO₄), and concentrated. The resulting residue

was purified by column chromatography (EtOAc/petroleum ether,

1:4 Ǟ 1:1). Yield: 604 mg (75%). R_fϭ 0.30 (EtOAc/petroleum

ether, 1:2). [α]²_D²ϭ Ϫ5.0 (c ϭ 1.0, CH₂Cl₂). IR (KBr): ν˜_maxϭ 3480,

furanose (38): Conventional acetylation of 34 (245 mg, 0.86 mmol)

and purification by column chromatography using EtOAc/petro-

leum ether (1:2) as an eluent gave 36. Yield: 235 mg (83%). R_fϭ

0.50 (EtOAc/petroleum ether, 1:2). [α]²_D²ϭ Ϫ7.0 (c ϭ 0.99, CH₂Cl₂).

IR (KBr): ν˜_maxϭ 2990, 2104, 1748, 1375, 1227, 1032 cm^{Ϫ1 1}H

.

NMR (500 MHz, CDCl₃): δ ϭ 1.29 (s, 3 H, Me), 1.51 (s, 3 H, Me),

2.07 (s, 3 H, MeCO), 2.08 (s, 3 H, MeCO), 3.89 (ddd, J_5,6aϭ 2.8,

J_5,6bϭ 6.9, J_4,5ϭ 10.1 Hz, 1 H, 5-H), 3.96 (dd, J_3,4ϭ 1.4, J_4,5

ϭ

2939, 2103, 1744, 1379, 1260, 1094 cm^{Ϫ1 1}H NMR (300 MHz,

.

10.1 Hz, 1 H, 4-H), 4.20 (dd, J_5,6bϭ 6.9, J_6a,6bϭ 11.7 Hz, 1 H,

6b-H), 4.53 (dd, J_5,6aϭ 2.8, J_6a,6bϭ 11.7 Hz, 1 H, 6a-H), 4.55 (d,

J_1,2ϭ 3.8 Hz, 1 H, 2-H), 5.29 (d, J_3,4ϭ 1.4 Hz, 1 H, 3-H), 5.90

(d, J_1,2ϭ 3.8 Hz, 1 H, 1-H) ppm. ¹³C NMR (125.7 MHz, CDCl₃):

δ ϭ 20.6, 20.7 (MeCO), 25.5, 26.5 (CMe₂), 60.4 (C-5), 63.9 (C-6),

77.4 (C-3), 83.5 (C-2), 84.1 (C-4), 106.2 (C-1), 112.8 (CMe₂), 169.5,

170.3 (CO) ppm. FAB-MS: m/z ϭ 314 (100) [M Ϫ Me]^ϩ.

C₁₃H₁₉N₃O₇(329.31): calcd. C 47.41, H 5.81, N 12.76; found C

47.31, H 5.63, N 12.61.

CDCl₃): δ ϭ 1.31 (s, 3 H, Me), 1.55 (s, 3 H, Me), 2.10 (s, 3 H,

MeCO), 3.76 (ddd, J_5,6aϭ 4.1, J_5,6bϭ 5.2, J_4,5ϭ 9.7 Hz, 1 H, 5-

H), 3.84 (dd, J_5,6bϭ 5.2, J_6a,6bϭ 11.5 Hz, 1 H, 6b-H), 3.99 (dd,

J_5,6aϭ 4.1, J_6a,6bϭ 11.5 Hz, 1 H, 6a-H), 4.04 (dd, J_3,4ϭ 1.4, J_4,5ϭ

9.7 Hz, 1 H, 4-H), 4.59 (d, J_1,2ϭ 3.8 Hz, 1 H, 2-H), 5.30 (d, J_3,4ϭ

1.4 Hz, 1 H, 3-H), 5.92 (d, J_1,2ϭ 3.8 Hz, 1 H, 1-H) ppm. ¹³C NMR

(75.5 MHz, CDCl₃): δ ϭ 20.7 (MeCO), 25.4, 26.4 (CMe₂), 62.7 (C-

5), 62.9 (C-6), 77.4 (C-3), 84.1 (C-2), 84.4 (C-4), 87.2 (CPh₃), 105.9

(C-1), 112.9 (CMe₂), 169.8 (CO) ppm. FAB-MS: m/z ϭ 310 (40)

[M ϩ Na]^ϩ. C₁₁H₁₇N₃O₆(287.27): calcd. C 45.99, H 5.96, N 14.63;

found C 45.90, H 6.02, N 14.63.

3,6-Di-O-acetyl-5-deoxy-1,2-O-isopropylidene-5-(NЈ-phenyl-

carbodiimido)-β-

L-altrofuranose (39): Compound 39 was obtained

1814

 2004 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim

www.eurjoc.org

Eur. J. Org. Chem. 2004, 1803Ϫ1819

Synthesis of Calystegine B₂, B₃, and B₄Analogues

from azide 38 (235 mg, 0.71 mmol) by an aza-Wittig-type reaction (1S,2S,3S,4R,5R)-2,3,4-Trihydroxy-6-oxa-N-(NЈ-phenylcarbamoyl)-

FULL PAPER

with phenyl isothiocyanate (115 mg, 0.85 mmol, 1.2 equiv.), and

TPP (205 mg, 0.78 mmol, 1.1 equiv.) in toluene (2 mL), following

the procedure described above for the preparation of -gulofur-

nor-tropane (42): Purification by column chromatography using

EtOAc/EtOH (50:1 Ǟ 10:1) as an eluent. Yield: 133 mg (95%).

R_fϭ 0.26 (EtOAc/EtOH/H₂O, 45:5:3). [α]²_D²ϭ ϩ82.9 (c ϭ 0.82,

anose-derived carbodiimides. Purification was effected by column H₂O). ¹H NMR (500 MHz, D₂O): δ ϭ 3.75 (m, 2 H, 3-H, 4-H),

chromatography using EtOAc/petroleum ether (1:5 Ǟ 1:3) as an

eluent. Yield: 129 mg (45%). R_fϭ 0.36 (EtOAc/petroleum ether,

1:3). [α]²_D²ϭ Ϫ12.3 (c ϭ 1.0, CH₂Cl₂). IR (KBr): ν˜_maxϭ 3061,

3.84 (bd, J_7a,7bϭ 8.6 Hz, 1 H, 7a-H), 3.88 (dd, J_1,7bϭ 4.5, J_7a,7bϭ

8.6 Hz, 1 H, 7b-H), 4.10 (m, 1 H, 2-H), 4.80 (t, J_1,2ϭ J_1,7b

4.5 Hz, 1 H, 1-H), 5.71 (d, J_4,5ϭ 1.0 Hz, 1 H, 5-H), 7.21Ϫ7.40 (m,

5 H, Ph) ppm. ¹³C NMR (125.7 MHz, D₂O): δ ϭ 59.3 (C-1), 67.6

(C-7), 70.6 (C-2), 71.6 (C-3), 74.2 (C-4), 88.3 (C-5), 123.9Ϫ138.5

ϭ

2988, 2137, 1748, 1593, 1501, 1375, 1225, 1101 cm^Ϫ^{1 1}H NMR

.

(500 MHz, CDCl₃): δ ϭ 1.29 (s, 3 H, Me), 1.53 (s, 3 H, Me), 1.91

(s, 3 H, MeCO), 2.08 (s, 3 H, MeCO), 4.07 (ddd, J_5,6aϭ 2.6, J_5,6bϭ (Ph), 158.2 (CO) ppm. FAB-MS: m/z ϭ 281 (70) [M ϩ H]^ϩ.

5.4, J_4,5ϭ 10.0 Hz, 1 H, 5-H), 4.09 (d, J_4,5ϭ 10.0 Hz, 1 H, 4-H),

C₁₃H₁₆N₂O₅(280.28): calcd. C 55.71, H 5.75, N 9.99; found C

4.22 (dd, J_5,6bϭ 5.4, J_6a,6bϭ 11.7 Hz, 1 H, 6b-H), 4.54 (dd, J_5,6aϭ 55.69, H 6.03, N 10.02.

2.6, J_6a,6bϭ 11.7 Hz, 1 H, 6a-H), 4.56 (d, J_1,2ϭ 3.8 Hz, 1 H, 2-

3-O-Acetyl-1,2-O-isopropylidene-6-O-trityl-α-D-allofuranose (44):

H), 5.39 (s, 1 H, 3-H), 5.92 (d, J_1,2ϭ 3.8 Hz, 1 H, 1-H), 7.08Ϫ7.29

(m, 5 H, Ph) ppm. ¹³C NMR (125.7 MHz, CDCl₃): δ ϭ 20.4, 20.7

(2 MeCO), 25.5, 26.5 (CMe₂), 57.3 (C-5), 64.3 (C-6), 77.6 (C-3),

84.1 (C-2), 84.7 (C-4), 106.2 (C-1), 112.7 (CMe₂), 123.7, 125.1,

129.3, 136.9 (Ph), 138.9 (NCN), 169.4, 170.3 (CO) ppm. FAB-MS:

m/z ϭ 427 (100) [M ϩ Na]^ϩ. C₂₀H₂₄N₂O₇(404.41): calcd. C 59.40,

H 5.98, N 6.93; found C 59.77, H 6.16, N 6.69.

1,2:5,6-Di-O-isopropylidene-α--allofuranose (43) (1.6 g, 6.2 mmol)

was acetylated and the crude acetate was treated with 40% aqueous

acetic acid (16 mL) at 40 °C for 24 h. The solvents were eliminated

under reduced pressure, and coevaporated several times with water

to give the corresponding 5,6-diol as a homogeneous product

(TLC), which was dissolved in pyridine (10 mL). Trityl chloride

(2.0 g, 7.2 mmol, 1.2 equiv.) was added and the reaction mixture

was stirred at room temperature for 24 h, then poured into ice-

water (60 mL) and decanted. The resulting solid was dissolved in

toluene (30 mL), washed with iced aqueous 10% acetic acid

(12 mL), aqueous saturated NaHCO₃(12 mL), dried (MgSO₄), and

concentrated. The residue was purified by column chromatography

using EtOAc/petroleum ether (1:3). Yield: 2.3 g (74%). R_fϭ 0.68

(EtOAc/petroleum ether, 1:3). [α]²_D²ϭ ϩ60.0 (c ϭ 1.0, CH₂Cl₂). IR

3,6-Di-O-acetyl-5-deoxy-1,2-O-isopropylidene-5-(NЈ-phenylureido)-

β-L-altrofuranose (40): Compound 40 was obtained from carbodii-

mide 39 (243 mg, 0.6 mmol) by TFA-catalyzed addition of water,

following the procedure described above for the preparation of -

gulofuranose-derived ureas. Purification was effected by column

chromatography using EtOAc/petroleum ether (2:1) as an eluent.

Yield: 223 mg (88%). R_fϭ 0.55 (EtOAc/petroleum ether, 3:1).

[α]²_D²ϭ ϩ42.0 (c ϭ 1.0, CH₂Cl₂). IR (KBr): ν˜_maxϭ 3360, 3057,

1

(KBr): ν˜_maxϭ 3489, 3059, 2988, 1744, 1375, 1240, 1074 cm^Ϫ1. H

2988, 1746, 1557, 1377, 1233, 1099 cm^Ϫ^{1 1}H NMR (500 MHz,

.

NMR (500 MHz, CDCl₃): δ ϭ 1.32 (s, 3 H, Me), 1.54 (s, 3 H, Me),

1.99 (s, 3 H, MeCO), 3.16 (dd, J_5,6bϭ 7.6, J_6a,6bϭ 9.7 Hz, 6b-H),

CDCl₃): δ ϭ 1.30 (s, 3 H, Me), 1.87 (s, 3 H, Me), 2.04 (s, 3 H,

MeCO), 2.08 (s, 3 H, MeCO), 4.03 (d, J_4,5ϭ 10.6 Hz, 1 H, 4-H),

4.31 (dd, J_5,6bϭ 3.2, J_6a,6bϭ 11.3 Hz, 1 H, 6b-H), 4.39 (dd, J_5,6aϭ

4.0, J_6a,6bϭ 11.3 Hz, 1 H, 6a-H), 4.53 (m, 1 H, 5-H), 4.66 (d, J_1,2ϭ

3.9 Hz, 1 H, 2-H), 5.20 (br. s, 1 H, NH), 5.24 (s, 1 H, 3-H), 5.96

(d, J_1,2ϭ 3.9 Hz, 1 H, 1-H), 6.79 (br. s, 1 H, NЈH), 7.03Ϫ7.36 (m,

5 H, Ph) ppm. ¹³C NMR (125.7 MHz, CDCl₃): δ ϭ 20.7, 20.8,

(MeCO), 25.5, 26.4 (CMe₂), 50.1 (C-5), 63.6 (C-6), 78.4 (C-3), 83.9

(C-2), 84.9 (C-4), 106.2 (C-1), 112.8 (CMe₂), 120.8Ϫ138.2 (Ph),

154.9 (CO urea), 170.3, 170.7 (CO) ppm. FAB-MS: m/z ϭ 445 (100)

[M ϩ Na]^ϩ. C₂₀H₂₆N₂O₈(422.43): calcd. C 56.69, H 6.20, N 6.63;

found C 56.65, H 6.23, N 6.56.

3.23 (dd, J_5,6aϭ 4.1, J_6a,6bϭ 9.7 Hz, 1 H, 6a-H), 4.13 (ddd, J_4,5

ϭ

3.8, J_5,6aϭ 4.1, J_5,6bϭ 7.6 Hz, 1 H, 5-H), 4.18 (dd, J_3,4ϭ 8.6,

J_4,5ϭ 3.8 Hz, 1 H, 4-H), 4.79 (dd, J_1,2ϭ 3.8, J_2,3ϭ 5.0 Hz, 1 H,

2-H), 4.85 (dd, J_2,3ϭ 5.0, J_3,4ϭ 8.6 Hz, 1 H, 3-H), 5.78 (d, J_1,2

ϭ

3.8 Hz, 1 H, 1-H), 7.23Ϫ7.43 (m, 15 H, 3 Ph) ppm. ¹³C NMR

(125.7 MHz, CDCl₃): δ ϭ 20.6 (MeCO), 26.6, 26.7 (CMe₂), 64.2

(C-6), 70.3 (C-5), 71.8 (C-3), 77.7 (C-4), 77.8 (C-2), 87.0 (CPh₃),

104.1 (C-1), 113.0 (CMe₂), 127.2Ϫ143.7 (Ph), 170.0 (CO) ppm.

FAB-MS: m/z ϭ 527 (90) [M ϩ Na]^ϩ. C₃₀H₃₂O₇(504.57): calcd. C

71.41, H 6.39; found C 71.80, H, 6.42.

3-O-Acetyl-5-azido-5-deoxy-1,2-O-isopropylidene-β-L-talofuranose

N-Thiocarbamoyl and N-Carbamoyl-6-oxa-(؉)-calystegine B₃De-

rivatives 41 and 42. General Procedure: Compounds 41 and 42 were

obtained from thiourea 37 and urea 40 (0.5 mmol), respectively, by

sequential deacetylation (for 40) and TFA-catalyzed hydrolysis of

the isopropylidene group, following the procedure described above

for the preparation of 6-oxa-(Ϫ)-calystegine B₄derivatives.

(45): Pyridine (0.4 mL) and trifluoromethanesulfonic anhydride

(0.83 mL, 5.0 mmol) were added to a solution of 44 (1.8 g,

3.6 mmol) in CH₂Cl₂(10 mL) at Ϫ25 °C under N₂. The reaction

mixture was allowed to reach room temperature and stirred for

30 min, then diluted with CH₂Cl₂(10 mL), washed with saturated

aqueous NaHCO₃(8 mL), dried (MgSO₄), and concentrated. The

(1S,2S,3S,4R,5R)-2,3,4-Trihydroxy-6-oxa-N-(NЈ-phenylthiocarba- resulting crude triflate ester was dissolved in DMF (15 mL), NaN₃

moyl)-nor-tropane (41): Purification by column chromatography

using EtOAc/EtOH (50:1) as an eluent. Yield: 95 mg (64%). R_fϭ

0.38 (EtOAc/EtOH/H₂O, 45:5:3). [α]²_D²ϭ ϩ71.0 (c ϭ 1.0, H₂O).

UV (MeOH): 248 nm (ε_m 18.0). H NMR (500 MHz, D₂O): δ ϭ

3.74 (dd, J_2,3ϭ 3.5, J_3,4ϭ 8.7 Hz, 1 H, 3-H), 3.76 (dd, J_3,4ϭ 8.7,

J_4,5ϭ 1.5 Hz, 1 H, 4-H), 3.85 (d, J_1,7aϭ J_1,7bϭ 2.9 Hz, 2 H, 7a-

(2.4 g, 36.9 mmol, 7 equiv.) was added and the reaction mixture

was stirred at room temperature for 3.5 h. The solvent was elimin-

ated under reduced pressure and the resulting residue was dissolved

in CH₂Cl₂(20 mL), the organic solution was washed with water (2

ϫ 10 mL), dried, and concentrated. BF₃·Et₂O (1.1 mL) and MeOH

(5.4 mL) were added to a solution of the crude tritylated azido

derivative thus obtained in CH₂Cl₂(29 mL) at 0 °C under Ar. The

1

H, 7b-H), 4.08 (t, J_1,2ϭ J_2,3ϭ 3.5 Hz, 1 H, 2-H), 5.07 (dt, J_1,2

ϭ

3.5, J_1,7aϭ J_1,7bϭ 2.9 Hz, 1 H, 1-H), 6.01 (d, J_4,5ϭ 1.5 Hz, 1 H, reaction mixture was allowed to reach room temperature and

5-H), 7.16Ϫ7.26 (m, 5 H, Ph) ppm. ¹³C NMR (125.7 MHz, D₂O):

stirred for 2 h, then washed with saturated aqueous NaHCO₃(2 ϫ

δ ϭ 60.8 (C-1), 70.3 (C-7), 71.7 (C-2), 71.8 (C-3), 74.6 (C-4), 90.3 10 mL), dried (MgSO₄), and concentrated. The resulting residue

(C-5), 128.3Ϫ140.1 (Ph), 180.8 (CS) ppm. FAB-MS: m/z ϭ 297 was purified by column chromatography using EtOAc/petroleum

(100) [M ϩ H]^ϩ. C₁₃H₁₆N₂O₄S (296.34): calcd. C 52.69, H 5.44, N ether (1:3 Ǟ 1:2). Yield: 620 mg (60%). R_fϭ 0.18 (EtOAc/petro-

9.45; found C 52.51, H 5.38, N 9.33.

leum ether, 1:2). [α]²_D²ϭ ϩ137.1 (c ϭ 0.97, CH₂Cl₂). IR (KBr):

Eur. J. Org. Chem. 2004, 1803Ϫ1819

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 2004 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim

1815

´

M. I. Garcıa-Moreno, C. Ortiz Mellet, J. M. Garcıa Fernandez

FULL PAPER

ν˜_maxϭ 3489, 2988, 2114, 1746, 1377, 1242, 1074 cm^Ϫ1. H NMR (s, 3 H, Me), 2.11 (s, 3 H, MeCO), 2.13 (s, 3 H, MeCO), 3.66 (ddd,

(500 MHz, CDCl₃): δ ϭ 1.32 (s, 3 H, Me), 1.54 (s, 3 H, Me), 2.13 J_4,5ϭ 2.9, J_5,6aϭ 4.6, J_5,6bϭ 8.4 Hz, 1 H, 5-H), 4.19 (dd, J_3,4

(s, 3 H, MeCO), 3.51 (ddd, J_4,5ϭ 3.1, J_5,6aϭ 5.2, J_5,6bϭ 6.8 Hz, 8.7, J_4,5ϭ 2.9 Hz, 1 H, 4-H), 4.33 (dd, J_5,6bϭ 8.4, J_6a,6bϭ 11.7 Hz,

1 H, 5-H), 3.91 (m, 2 H, 6a-H, 6b-H), 4.25 (dd, J_3,4ϭ 8.6, J_4,5

1

ϭ

1 H, 6b-H), 4.38 (dd, J_5,6aϭ 4.6, J_6a,6bϭ 11.7 Hz, 1 H, 6a-H),

4.82 (dd, J_1,2ϭ 3.6, J_2,3ϭ 4.8 Hz, 1 H, 2-H), 4.87 (dd, J_2,3ϭ 4.8,

J_3,4ϭ 8.7 Hz, 1 H, 3-H), 5.82 (d, J_1,2ϭ 3.6 Hz, 1 H, 1-H) ppm.

3.1 Hz, 1 H, 4-H), 4.84 (dd, J_1,2ϭ 3.6, J_2,3ϭ 4.9 Hz, 1 H, 2-H),

4.87 (dd, J_2,3ϭ 4.9, J_3,4ϭ 8.6 Hz, 1 H, 3-H), 5.83 (d, J_1,2ϭ 3.6 Hz,

1 H, 1-H) ppm. ¹³C NMR (75.5 MHz, CDCl₃): δ ϭ 20.5 (MeCO), ¹³C NMR (125.7 MHz, CDCl₃): δ ϭ 20.6 (MeCO), 26.5, 26.6

26.4, 26.5 (CMe₂), 61.5 (C-5), 62.8 (C-6), 72.7 (C-3), 76.9 (C-4), (CMe₂), 59.2 (C-5), 64.0 (C-6), 72.7 (C-3), 77.0 (C-4), 77.2 (C-2),

77.4 (C-2), 104.2 (C-1), 113.3 (CMe₂), 170.3 (CO) ppm. FAB-MS: 104.3 (C-1), 113.4 (CMe₂), 170.0, 170.4 (CO) ppm. FAB-MS: m/

m/z ϭ 310 (85) [M ϩ Na]^ϩ. C₁₁H₁₇N₃O₆(287.27): calcd. C 45.99,

z ϭ 100 (40) [M ϩ H]^ϩ. C₁₃H₁₉N₃O₇(329.31): calcd. C 47.41, H

H 5.96, N 14.63; found C 45.95, H 5.91, N 14.34.

5.81, N 12.76; found C 47.26, H 5.75, N 12.60.

3,6-Di-O-acetyl-5-deoxy-1,2-O-isopropylidene-5-(NЈ-phenylcarbo-

diimido)-β-L-talofuranose (50): Compound 50 was obtained from

5-Azido-5-deoxy-1,2-O-isopropylidene-β-L-talofuranose (46): Con-

ventional deacetylation of 45 (209 mg, 0.73 mmol) afforded 45.

azide 49 (198 mg, 0.60 mmol) by an aza-Wittig-type reaction with

phenyl isothiocyanate (97 mg, 0.72 mmol, 1.2 equiv.) and TPP

(173 mg, 0.66 mmol, 1.1 equiv.) in toluene (1.5 mL), following the

procedure described above for the preparation of -gulofuranose-

derived carbodiimides. Purification was effected by column chro-

matography using EtOAc/petroleum ether (1:4) as an eluent. Yield:

Yield: 165 mg (92%). R_fϭ 0.35 (EtOAc/petroleum ether, 1:2). [α]

22

ϭ ϩ43.3 (c ϭ 0.9, MeOH). IR (KBr): ν˜_maxϭ 3468, 2988, 2104,

D

1377, 1107 cm^Ϫ1. ¹H NMR (300 MHz, CD₃OD): δ ϭ 1.33 (s, 3 H,

Me), 1.51 (s, 3 H, Me), 3.46 (ddd, J_4,5ϭ 3.6, J_5,6aϭ 5.4, J_5,6b

ϭ

7.7 Hz, 1 H, 5-H), 3.76 (dd, J_5,6bϭ 7.7, J_6a,6bϭ 11.6 Hz, 1 H, 6b-

H), 3.81 (dd, J_5,6aϭ 5.4, J_6a,6bϭ 11.6 Hz, 1 H, 6a-H), 3.89 (dd,

175 mg (71%). R_fϭ 0.14 (EtOAc/petroleum ether, 1:3). [α]²_D²

ϭ

J_3,4ϭ 9.0, J_4,5ϭ 3.6 Hz, 1 H, 4-H), 4.00 (dd, J_2,3ϭ 4.5, J_3,4

ϭ

ϩ110.0 (c ϭ 1.1, CH₂Cl₂). IR (KBr): ν˜_maxϭ 3063, 2990, 2131,

9.0 Hz, 1 H, 3-H), 4.56 (dd, J_1,2ϭ 3.6, J_2,3ϭ 4.5 Hz, 1 H, 2-H),

5.72 (d, J_1,2ϭ 3.6 Hz, 1 H, 1-H) ppm. ¹³C NMR (75.5 MHz,

CD₃OD): δ ϭ 26.6, 26.9 (CMe₂), 63.1 (C-5), 64.4 (C-6), 73.5 (C-

3), 80.2 (C-4), 80.7 (C-2), 105.3 (C-1), 114.0 (CMe₂) ppm. FAB-

MS: m/z ϭ 268 (100) [M ϩ Na]^ϩ. C₉H₁₅N₃O₅(245.23): calcd. C

44.08, H 6.16, N. 17.13; found C 43.96, H. 6.05, N 17.07.

1

1748, 1589, 1381, 1231, 1101 cm^Ϫ1. H NMR (300 MHz, CDCl₃):

δ ϭ 1.34 (s, 3 H, Me), 1.55 (s, 3 H, Me), 1.98 (s, 3 H, MeCO), 2.15

(s, 3 H, MeCO), 3.93 (ddd, J_4,5ϭ 2.2, J_5,6aϭ 5.0, J_5,6bϭ 8.1 Hz,

1 H, 5-H), 4.23 (dd, J_3,4ϭ 8.7, J_4,5ϭ 2.2 Hz, 1 H, 4-H), 4.33 (dd,

J_5,6bϭ 8.1, J_6a,6bϭ 11.4 Hz, 1 H, 6b-H), 4.39 (dd, J_5,6aϭ 5.0,

J_6a,6bϭ 11.4 Hz, 1 H, 6a-H), 4.84 (dd, J_1,2ϭ 3.6, J_2,3ϭ 4.7 Hz, 1

H, 2-H), 4.93 (dd, J_2,3ϭ 4.7, J_3,4ϭ 8.7 Hz, 1 H, 3-H), 5.82 (d,

J_1,2ϭ 3.6 Hz, 1 H, 1-H), 7.10Ϫ7.32 (m, 5 H, Ph) ppm. ¹³C NMR

(75.5 MHz, CDCl₃): δ ϭ 20.5 (MeCO), 26.5, 26.6 (CMe₂), 56.2 (C-

5), 64.9 (C-6), 72.7 (C-3), 76.7 (C-4), 77.1 (C-2), 104.2 (C-1), 113.3

(CMe₂), 123.7Ϫ134.7 (Ph), 139.0 (NCN), 169.9, 170.4 (CO) ppm.

FAB-MS: m/z ϭ 427 (40) [M ϩ Na]^ϩ, 405 (100) [M ϩ H]^ϩ.

C₂₀H₂₄N₂O₇(404.41): calcd. C 59.39, H 5.98, N, 6.93; found C

59.56, H 5.75, N 6.89.

5-Amino-5-deoxy-1,2-O-isopropylidene-β-L-talofuranose (47):

A

solution of 46 (277 mg, 1.13 mmol) in MeOH (11 mL) was hydro-

genated at atmospheric pressure for 2 h using 10% Pd/C (112 mg)

as catalyst. The suspension was filtered through Celite and concen-

trated to give 46 as a hygroscopic solid which was used in the next

step without further purification.

5-Deoxy-1,2-O-isopropylidene-5-(NЈ-phenylthioureido)-β-L-talofura

nose (48): Compound 48 was obtained by the coupling reaction of

amine 47 (138 mg, 0.63 mmol) with phenyl isothiocyanate, follow-

ing the procedure described above for the preparation of -gulofur-

anose-derived thioureas. Purification was effected by column chro-

matography using EtOAc/petroleum ether (2:1) as an eluent. Yield:

3,6-Di-O-acetyl-5-deoxy-1,2-O-isopropylidene-5-(NЈ-phenylureido)-

β-L-talofuranose (51): Compound 51 was obtained from carbodiim-

ide 50 (150 mg, 0.37 mmol) by TFA-catalyzed addition of water,

following the procedure described above for the preparation of -

gulofuranose-derived ureas. Purification was effected by column

chromatography using EtOAc/petroleum ether (2:1) as an eluent.

Yield: 144 mg (92%). R_fϭ 0.69 (EtOAc/petroleum ether, 3:1).

[α]²_D²ϭ ϩ84.3 (c ϭ 1.02, CH₂Cl₂). IR (KBr): ν˜_maxϭ 3351, 3055,

145 mg (65%). R_fϭ 0.33 (EtOAc/petroleum ether, 3:1). [α]²_D²

ϭ

ϩ13.0 (c ϭ 1.0, CH₂Cl₂). UV (CH₂Cl₂): 267 nm (ε_m 15.7). IR

1

(KBr): ν˜_maxϭ 3350, 2934, 1603, 1589, 1387, 1072 cm^Ϫ1. H NMR

(300 MHz, CDCl₃, 313 K): δ ϭ 1.32 (s, 3 H, Me), 1.55 (s, 3 H,

Me), 3.79 (dd, J_5,6bϭ 4.8, J_6a,6bϭ 11.6 Hz, 1 H, 6b-H), 3.89 (dd,

2988, 1746, 1533, 1375, 1238, 1074 cm^Ϫ1

CDCl₃): δ ϭ 1.31 (s, 3 H, Me), 1.53 (s, 3 H, Me), 2.05 (s, 3 H,

MeCO), 2.12 (s, 3 H, MeCO), 4.12 (dd, J_5,6bϭ 5.7, J_6a,6b

.

¹H NMR (500 MHz,

J_2,3ϭ 4.5, J_3,4ϭ 9.0 Hz, 1 H, 3-H), 3.94 (dd, J_5,6aϭ 3.5, J_6a,6b

11.6 Hz, 1 H, 6a-H), 4.10 (dd, J_3,4ϭ 9.0, J_4,5ϭ 1.9 Hz, 1 H, 4-H),

4.57 (dd, J_1,2ϭ 3.6, J_2,3ϭ 4.5 Hz, 1 H, 2-H), 4.88 (dddd, J_4,5

ϭ

10.8 Hz, 1 H, 6b-H), 4.27 (dd, J_4,5ϭ 1.3, J_3,4ϭ 9.2 Hz, 1 H, 4-H),

4.30 (dd, J_5,6aϭ 6.7, J_6a,6bϭ 10.8 Hz, 1 H, 6a-H), 4.33 (m, 1 H,

5-H), 4.63 (dd, J_2,3ϭ 4.6, J_3,4ϭ 9.2 Hz, 1 H, 3-H), 4.80 (dd, J_1,2ϭ

3.7, J_2,3ϭ 4.6 Hz, 1 H, 2-H), 5.21 (d, J_5,NHϭ 9.1 Hz, 1 H, NH),

5.71 (d, J_1,2ϭ 3.7 Hz, 1 H, 1-H), 6.91 (br. s, 1 H, NЈH), 7.05Ϫ7.29

(m, 5 H, Ph) ppm. ¹³C NMR (125.7 MHz, CDCl₃): δ ϭ 20.6, 20.8

(MeCO), 26.5, 26.6 (CMe₂), 48.1 (C-5), 64.3 (C-6), 72.4 (C-3), 76.4

(C-4), 77.1 (C-2), 104.2 (C-1), 113.4 (CMe₂), 120.7Ϫ138.3 (Ph),

155.2 (CO urea), 171.1, 170.3 (CO) ppm. FAB-MS: m/z ϭ 445 (100)

[M ϩ Na]^ϩ. C₂₀H₂₆N₂O₈(422.43): calcd. C 56.69, H 6.20, N 6.63;

found C 56.49, H 6.23, N 6.46.

1.9, J_5,6aϭ 3.5, J_5,6bϭ 4.8, J_5,NHϭ 8.6 Hz, 1 H, 5-H), 6.14 (d,

J_1,2ϭ 3.6 Hz, 1 H, 1-H), 6.84 (d, J_5,NHϭ 8.6 Hz, 1 H, NH),

7.22Ϫ7.44 (s, 5 H, Ph), 8.30 (br. s, 1 H, NЈH) ppm. ¹³C NMR

(75.5 MHz, CDCl₃, 313 K): δ ϭ 26.0, 26.4 (CMe₂), 54.4 (C-5), 64.1

(C-6), 71.4 (C-3), 78.3 (C-2), 81.2 (C-4), 103.8 (C-1), 113.2 (CMe₂),

181.0 (CS) ppm. FAB-MS: m/z ϭ 377 (100) [M ϩ Na]^ϩ.

C₁₆H₂₂N₂O₅S (354.42): calcd. C 54.22, H 6.25, N 7.90; found C

54.28, H 6.24, N 7.83.

3,6-Di-O-acetyl-5-azido-5-deoxy-1,2-O-isopropylidene-β-L-talo-

furanose (49): Conventional acetylation of 45 (219 mg, 0.76 mmol)

and purification by column chromatography using EtOAc/petro-

5-Deoxy-5-(NЈ-phenylthioureido)-L-talofuranose (52) and (1S,2R,3R,

leum ether (1:3) as an eluent gave 49. Yield: 236 mg (94%). R_fϭ 4R,5R)-2,3,4-Trihydroxy-6-oxa-N-(NЈ-phenylthiocarbamoyl)-

0.28 (EtOAc/petroleum ether, 1:3). [α]²_D²ϭ ϩ102.2 (c ϭ 0.91,

nor-tropane (53): TFA-catalyzed hydrolysis of the isopropylidene

CH₂Cl₂). IR (KBr): ν˜_maxϭ 2990, 2120, 1746, 1375, 1235, 1024 group of the protected thiourea 50 (150 mg, 0.42 mmol) and neu-

cm^Ϫ1

.

¹H NMR (500 MHz, CDCl₃): δ ϭ 1.33 (s, 3 H, Me), 1.53

tralization, following the procedure indicated above for the prep-

1816

 2004 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim

www.eurjoc.org

Eur. J. Org. Chem. 2004, 1803Ϫ1819

Synthesis of Calystegine B₂, B₃, and B₄Analogues

FULL PAPER

aration of calystegine B₄derivatives afforded a mixture of 52 and

53 (5-H resonance at δ ϭ 5.98 ppm) in a ratio of 95:5 (¹H NMR in

D₂O). Purification was effected by column chromatography using

EtOAc Ǟ EtOAc/EtOH/H₂O (45:5:3) as an eluent. Yield: 122 mg

(92%). R_fϭ 0.50 (EtOAc/EtOH/H₂O, 45:5:3). UV (MeOH) 250 nm

(ε_m 13.0). The following data correspond to the furanose species

52: Anomer ratio β/α ϭ 2:1 (1-H integration). ¹H NMR (500 MHz,

26.0, 26.4 (CMe₂), 63.9 (C-6), 68.0 (C-5), 76.4 (C-3), 79.2 (C-4),

82.9 (C-2), 104.7 (C-1), 112.2 (CMe₂), 171.0 (CO) ppm. FAB-MS:

m/z ϭ 285 (25) [M ϩ Na]^ϩ, 263 (25) [M ϩ H]^ϩ. C₁₁H₁₈O₇(262.26):

calcd. C 50.38, H 6.92; found C 50.22, H 6.81.

3-O-Acetyl-1,2-O-isopropylidene-6-O-trityl-α-L-glucofuranose (58):

Trityl chloride (543 mg, 1.94 mmol, 1.3 equiv.) was added to a solu-

tion of 57 (368 mg, 1.4 mmol) in pyridine (3 mL). The reaction

mixture was stirred at room temperature for 24 h, then poured into

ice-water (10 mL), and decanted. A solution of the resulting solid

in toluene (10 mL) was washed with iced aqueous 10% AcOH

(6 mL), aqueous saturated NaHCO₃(6 mL), dried (MgSO₄), and

concentrated. The residue was purified by column chromatography

using EtOAc/petroleum ether (1:3). Yield: 523 mg (74%). R_fϭ 0.43

(EtOAc/petroleum ether, 1:1). [α]²_D²ϭ ϩ19.8 (c ϭ 1.01, CH₂Cl₂).

D₂O, 313 K): δ ϭ 4.07 (m, 2 H, 6aα-H, 6bα-H), 4.40 (t, J_1,2

ϭ

J_2,3ϭ 5.7 Hz, 1 H, 2α-H), 4.08 (dd, J_5,6aϭ 6.5, J_6a,6bϭ 11.5 Hz,

1 H, 6aβ-H), 4.09 (m, 1 H, 6bβ-H), 4.20 (d, J_2,3ϭ 4.5 Hz, 1 H,

2β-H), 4.31 (m, 1 H, 3α-H), 4.45 (dd, J_4,5ϭ 2.5, J_3,4ϭ 7.5 Hz, 1

H, 4β-H), 4.51 (dd, J_2,3ϭ 4.5, J_3,4ϭ 7.5 Hz, 1 H, 3β-H), 4.52 (m,

1 H, 4α-H), 5.06 (m, 2 H, 5α-H, 5β-H), 5.43 (s, 1 H, 1β-H), 5.54

(br. s, 1 H, 1α-H), 7.21Ϫ7.43 (m, 5 H, Ph) ppm. ¹³C NMR

(125.7 MHz, D₂O, 313 K): δ ϭ 56.1 (C-5β), 56.6 (C-5α), 61.5 (C-

6α), 61.7 (C-6β), 70.5 (C-3β), 70.8 (C-3α), 74.9 (C-2α, C-2β), 80.3

(C-4β), 81.1 (C-4α), 96.8 (C-1α), 100.8 (C-1β), 126.2Ϫ136.1 (Ph),

IR (KBr): ν˜_maxϭ 3063, 2974, 1746, 1487, 1377, 1231, 1092 cm^Ϫ1

.

¹H NMR (500 MHz, CDCl₃): δ ϭ 1.31 (s, 3 H, Me), 1.51 (s, 3 H,

Me), 2.09 (s, 3 H, MeCO), 3.39 (m, 2 H, 6a-H, 6b-H), 3.83 (m, 1

H, 5-H), 4.38 (dd, J_3,4ϭ 1.0, J_4,5ϭ 9.1 Hz, 1 H, 4-H), 4.51 (d,

J_1,2ϭ 3.3 Hz, 1 H, 2-H), 5.34 (d, J_3,4ϭ 1.0 Hz, 1 H, 3-H), 5.86

(d, J_1,2ϭ 3.3 Hz, 1 H, 1-H), 7.46Ϫ7.22 (m, 15 H, 3 Ph) ppm. ¹³C

NMR (125.7.5 MHz, CDCl₃): δ ϭ 20.6 (MeCO), 26.0, 26.6

(CMe₂), 64.8 (C-6), 67.7 (C-5), 76.2 (C-3), 78.6 (C-4), 83.1 (C-2),

86.7 (CPh₃), 104.9 (C-1), 112.1 (CMe₂), 127.0Ϫ143.7 (Ph), 169.9

(CO) ppm. FAB-MS: m/z ϭ 527 (40) [M ϩ Na]^ϩ. C₃₀H₃₂O₇

(504.57): calcd. C 71.41, H 6.39; found C 71.53, H 6.44.

180.4 (CS) ppm. FAB-MS: m/z

ϭ 315 (100) [M ϩ

H]^ϩ.

C₁₃H₁₈N₂O₅S (296.34): calcd. C 49.67, H 5.68, N 8.91; found C

46.61, H 5.60, N 8.82.

5-Deoxy-5-(NЈ-phenylureido)-L-talofuranose (54) and (1S,2R,

3R,4R,5R)-2,3,4-Trihydroxy-6-oxa-N-(NЈ-phenylcarbamoyl)nor--

tropane (55): Sequential deacetylation and TFA-catalyzed hydroly-

sis of the isopropylidene group of the protected urea 51 (130 mg,

0.31 mmol) and further neutralization, following the procedure

indicated above for the preparation of calystegine B₄derivatives,

afforded a mixture of 54 and 55 (5-H resonance at δ ϭ 5.59 ppm)

in 95:2 relative proportions (¹H NMR in D₂O). Purification was

effected by column chromatography using EtOAc Ǟ EtOAc/EtOH/

H₂O (45:5:3) as an eluent. Yield: 74 mg (80%). R_fϭ 0.34 (EtOAc/

EtOH/H₂O, 45:5:3). The following data correspond to the furanose

3-O-Acetyl-5-azido-5-deoxy-1,2-O-isopropylidene-β-D-idofuranose

(59): Pyridine (0.18 mL) and trifluoromethanesulfonic anhydride

(0.23 mL, 1.39 mmol) were added to a solution of 58 (514 mg,

1.02 mmol) in CH₂Cl₂(4 mL), at Ϫ25 °C under N₂. The reaction

mixture was allowed to reach room temperature and stirred for

20 min, then diluted with CH₂Cl₂(10 mL), washed with saturated

aqueous NaHCO₃(8 mL), dried (MgSO₄), and concentrated. The

resulting crude triflate ester was dissolved in DMF (4 mL), NaN₃

(464 mg, 7.13 mmol, 7 equiv.) was added and the reaction mixture

was stirred at room temperature for 3.5 h. The solvent was elimin-

ated under reduced pressure and the resulting residue was dissolved

in CH₂Cl₂(20 mL), the organic solution was washed with water

(2 ϫ 10 mL), dried, and concentrated. The crude tritylated azido

derivative thus obtained was dissolved in CH₂Cl₂(8 mL) and

BF₃·Et₂O (300 mL) and MeOH (1.5 mL) were added at 0 °C under

Ar. The reaction mixture was allowed to reach room temperature,

stirred for 3.5 h, washed with saturated aqueous NaHCO₃(2 ϫ

4 mL), dried (MgSO₄), and concentrated. The residue was purified

by column chromatography using EtOAc/petroleum ether (1:3).

Yield: 193 mg (66%). R_fϭ 0.12 (EtOAc/petroleum ether, 1:2).

[α]²_D²ϭ ϩ33.6 (c ϭ 1.0, CH₂Cl₂). IR (KBr): ν˜_maxϭ 2988, 2106,

1

species 54: Anomer ratio β/α ϭ 1.9:1 (1-H integration). H NMR

(500 MHz, D₂O, 313 K): δ ϭ 3.68 (dd, J_5,6bϭ 7.0, J_6a,6bϭ 11.0 Hz,

1 H, 6bα-H), 3.70 (dd, J_5,6bϭ 7.0, J_6a,6bϭ 11.0 Hz, 1 H, 6bβ-H),

3.73 (dd, J_5,6aϭ 6.5, J_6a,6bϭ 11.0 Hz, 1 H, 6aα-H), 3.75 (dd,

J_5,6aϭ 6.0, J_6a,6bϭ 11.0 Hz, 1 H, 6aβ-H), 4.00 (dd, J_1,2ϭ 1.0,

J_2,3ϭ 5.0 Hz, 1 H, 2β-H), 4.10 (m, 3 H, 2α-H, 3α-H, 5β-H), 4.15

(dd, J_4,5ϭ 2.5, J_3,4ϭ 7.5 Hz, 1 H, 4β-H), 4.24 (m, 2 H, 4α-H, 5α-

H), 4.26 (dd, J_2,3ϭ 5.0, J_3,4ϭ 7.5 Hz, 1 H, 3β-H), 5.27 (d, J_1,2

ϭ

1.0 Hz, 1 H, 1β-H), 5.43 (br. s, 1 H, 1α-H), 7.18Ϫ7.36 (m, 5 H, Ph)

ppm. ¹³C NMR (125.7 MHz, D₂O, 313 K): δ ϭ 51.8 (C-5β), 52.1

(C-5α), 62.2 (C-6α), 62.4 (C-6β), 70.9 (C-3α, C-3β), 71.1 (C-2α),

75.2 (C-2β), 80.9 (C-4β), 81.7 (C-4α), 96.9 (C-1α), 101.1 (C-1β),

126.2Ϫ136.1 (Ph), 121.4Ϫ138.1 (Ph), 158.2 (CO urea), 180.4 (CS)

ppm. FAB-MS: m/z ϭ 321 (100) [M ϩ Na]^ϩ. C₁₃H₁₈N₂O₆(298.30):

calcd. C 52.34, H 6.08, N 9.39; found C 52.13, H 5.74, N 9.20.

1748, 1379, 1223, 1092 cm^{Ϫ1 1}H NMR (300 MHz, CDCl₃): δ ϭ

.

3-O-Acetyl-1,2-O-isopropylidene-α-L-glucofuranose (57): 1,2:5,6-Di-

1.31 (s, 3 H, Me), 1.52 (s, 3 H, Me), 2.12 (s, 3 H, MeCO), 3.56 (dd,

J_5,6bϭ 5.9, J_6a,6bϭ 11.3 Hz, 1 H, 6b-H), 3.70 (m, 1 H, 5-H), 3.74

(dd, J_5,6aϭ 3.9, J_6a,6bϭ 11.3 Hz, 1 H, 6a-H), 4.35 (dd, J_3,4ϭ 3.0,

J_4,5ϭ 7.8 Hz, 1 H, 4-H), 4.51 (d, J_1,2ϭ 3.8 Hz, 1 H, 2-H), 5.20

(d, J_3,4ϭ 3.0 Hz, 1 H, 3-H), 5.95 (d, J_1,2ϭ 3.8 Hz, 1 H, 1-H)

ppm. ¹³C NMR (75.5 MHz, CDCl₃): δ ϭ 20.6 (MeCO), 26.0, 26.5

(CMe₂), 62.1 (C-6), 62.2 (C-5), 76.0 (C-3), 78.7 (C-4), 83.4 (C-2),

104.3 (C-1), 112.3 (CMe₂), 169.6 (CO) ppm. FAB-MS: m/z ϭ 310

(15) [M ϩ Na]^ϩ, 288 (20) [M ϩ H]^ϩ. C₁₁H₁₇O₆N₃(287.27): calcd.

C 45.99, H 5.96, N 14.63; found C 45.99, H 5.87, N 14.64.

O-isopropylidene-α--glucofuranose (56) (468.50 mg, 1.8 mmol)

was sequentially acetylated and treated with 40% aqueous AcOH

(5 mL) at 40 °C for 4 h. The solvents were eliminated under re-

duced pressure, coevaporated several times with water and the re-

sulting residue was purified by column chromatography using

EtOAc/petroleum ether (1:1 Ǟ 4:1) as an eluent. Yield: 419 mg

(82%). R_fϭ 0.14 (EtOAc/petroleum ether, 1:1). [α]²_D²ϭ Ϫ23.3 (c ϭ

0.6, CH₂Cl₂). IR (KBr): ν˜_maxϭ 3457, 2969, 1744, 1381, 1258, 1092

cm^Ϫ1

(s, 3 H, Me), 2.13 (s, 3 H, MeCO), 3.68 (ddd, J_5,6aϭ 2.7, J_5,6b

5.7, J_4,5ϭ 8.8 Hz, 1 H, 5-H), 3.71 (dd, J_5,6bϭ 5.7, J_6a,6bϭ 10.9 Hz, 5-Azido-5-deoxy-1,2-O-isopropylidene-β-

1 H, 6b-H), 3.83 (dd, J_5,6aϭ 2.7, J_6a,6bϭ 10.9 Hz, 1 H, 6a-H), pound 60 was obtained by conventional deacetylation of 59

.

¹H NMR (300 MHz, CDCl₃): δ ϭ 1.30 (s, 3 H, Me), 1.50

ϭ

D-idofuranose (60): Com-

4.16 (dd, J_3,4ϭ 2.6, J_4,5ϭ 8.8 Hz, 1 H, 4-H), 4.55 (d, J_1,2ϭ 3.7 Hz, (170 mg, 0.59 mmol) and showed spectroscopic properties identical

1 H, 2-H), 5.26 (d, J_3,4ϭ 2.6 Hz, 1 H, 3-H), 5.89 (d, J_1,2ϭ 3.7 Hz, to those of the known α--ido enantiomer. It was used in the next

1 H, 1-H) ppm. ¹³C NMR (75.5 MHz, CDCl₃): δ ϭ 20.6 (MeCO), step without further purification.

Eur. J. Org. Chem. 2004, 1803Ϫ1819

www.eurjoc.org

 2004 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim

1817

´

M. I. Garcıa-Moreno, C. Ortiz Mellet, J. M. Garcıa Fernandez

FULL PAPER

5-Amino-5-deoxy-1,2-O-isopropylidene-β-

D

-idofuranose (61):

A

at 505 nm (for trehalase). The K_ivalue and enzyme inhibition mode

were determined from the slope of LineweaverϪBurk plots and

double reciprocal analysis using a Sigma Plot program (version

4.14, Jandel Scientific).

solution of azide 60 (0.59 mmol) in MeOH (5.6 mL) was hydrogen-

ated at atmospheric pressure for 2 h using 10% Pd/C (59 mg) as

catalyst. The suspension was filtered through Celite, and concen-

trated to give 61 as a hygroscopic solid that was used in next step

without further purification.

Acknowledgments

5-Deoxy-1,2-O-isopropylidene-5-(NЈ-phenylthioureido)-β-D-ido-

´

We thank the Ministerio de Ciencia y Tecnologıa for financial sup-

furanose (62): Phenyl isothiocyanate (80 mg, 0.59 mmol) was added

to a solution of amine 61 (170 mg, 0.59 mmol) in pyridine (5 mL).

The reaction mixture was stirred at room temperature for 18 h and

coevaporated several times with toluene. The resulting residue was

purified by column chromatography using EtOAc/petroleum ether

(2:1) as an eluent. Yield: 149 mg (71%). R_fϭ 0.41 (EtOAc/petro-

leum ether, 3:1). [α]²_D²ϭ Ϫ15.5 (c ϭ 1.0, MeOH). UV (MeOH):

249 nm (ε_m 13.1). IR (KBr): ν˜_maxϭ 3368, 3065, 2988, 1534, 1381,

´

port (grant no. BMC2001-2366-CO3-03) and the Fundacion Cam-

ara for a doctoral fellowship (M. I. G.-M.).

[1]

R. J. Molyneux, R. J. Nash, N. Asano, in: Alkaloids: Chemical

and Biological Perspectives (Ed.: S. W. Pelletier), Pergamon,

Oxford, 1996, Vol. 11, pp. 303Ϫ343.

[2]

W. J. Griffin, G. D. Lin, Phytochemistry 2000, 53, 623Ϫ637.

1092 cm^Ϫ^{1 1}H NMR (300 MHz, CD₃OD, 313 K): δ ϭ 1.29 (s, 3

.

[3]

A. A. Watson, D. R. Davies, N. Asano, B. Winchester, A. Kato,

H, Me), 1.44 (s, 3 H, Me), 3.73 (dd, J_5,6bϭ 5.3, J_6a,6bϭ 11.1 Hz,

1 H, 6b-H), 3.79 (dd, J_5,6aϭ 3.9, J_6a,6bϭ 11.1 Hz, 1 H, 6a-H),

4.15 (d, J_3,4ϭ 2.7 Hz, 1 H, 3-H), 4.37 (dd, J_3,4ϭ 2.7, J_4,5ϭ 7.0 Hz,

1 H, 4-H), 4.50 (d, J_1,2ϭ 3.7 Hz, 1 H, 2-H), 4.78 (m, 1 H, 5-H),

R. J. Molyneux, B. L. Stegelmair, R. J. Nash, in: ACS Synpos-

ium Series 745: Natural and Synthetic Toxins-Biological Impli-

cations (Eds.: A. T. Tu, W. Gaffield), American Chemical So-

ciety, Washington, DC, 2000, pp. 129Ϫ139.

[4]

5.87 (d, J_1,2ϭ 3.7 Hz, 1 H, 1-H), 7.17Ϫ7.39 (m, 5 H, Ph) ppm. ¹³

C

Although the term ‘‘azasugar’’ is widely used in the literature

to refer to glycomimetics where the endocyclic oxygen atom

has been replaced by nitrogen, the term is not strictly correct

according to the IUPAC-IUBMB nomenclature recommen-

dations for carbohydrates, the accepted term being ‘‘imino su-

gar’’. ‘‘Azahexose’’ would actually imply that a carbon atom

has been exchanged for a nitrogen atom. See: McNaught, A.

D. Pure Appl. Chem. 1996, 68, 1919Ϫ2008. By analogy with

the trivial name ‘‘azasugar’’, we are using here the term ‘‘sp²-

azasugar’’ to refer to glycomimetics where the endocyclic oxy-

gen atom has been replaced by a nitrogen atom with substan-

tial sp²character, typically a pseudoamide-type nitrogen.

NMR (75.5 MHz, CD₃OD, 313 K): δ ϭ 26.4, 27.1 (CMe₂), 56.6

(C-5), 62.4 (C-6), 75.9 (C-3), 80.6 (C-4), 87.0 (C-2), 104.9 (C-1),

112.8 (CMe₂), 125.4Ϫ139.6 (Ph), 181.6 (CS) ppm. FAB-MS: m/z ϭ

377 (50) [M ϩ Na]^ϩ, 355 (100) [M ϩ H]^ϩ. C₁₆H₂₂N₂O₅S (354.42):

calcd. C 54.22, H 6.25, N 7.90; found C 54.13, H 6.46, N 7.84.

6-Oxa-(؊)-calystegine B₂Derivative. (1R,2S,3R,4S,5S)-2,3,4-Trihy-

droxy-N-(NЈ-phenylthiocarbamoyl)-6-oxa-nor-tropane (63): A solu-

tion of 62 (130 mg, 0.37 mmol) in 90% TFA/H₂O (2 mL) was

stirred at room temperature for 15 min. The solvent was eliminated

under reduced pressure and the residue was coevaporated several

times with water. An aqueous solution was further neutralized with

Amberlite IRA 68 (OH^Ϫ) ion-exchange resin, filtered, and freeze-

dried. The residue was purified by column chromatography using

EtOAc Ǟ EtOAc/EtOH (20:1) Ǟ EtOAc/EtOH/H₂O (45:5:3).

[5]

N. Asano, Curr. Top. Med. Chem. 2003, 3, 471Ϫ484.

[6]

N. Asano, Glycobiology 2003, 13, 93RϪ104R.

[7]

V. H. Lillelund, H. H. Jensen, X. Liang, M. Bols, Chem. Rev.

2002, 102, 515Ϫ553.

A. A. Watson, G. W. J. Fleet, N. Asano, R. J. Molyneux, R. J.

Nash, Phytochemistry 2001, 56, 265Ϫ295.

A. Ossor, A. D. Elbein, in: Carbohydrates in Chemistry and

Biology (Eds.: B. Ernst, G. W. Hart, P. Sinay¨), Part II, Vol. 3,

Wiley-VCH, Weinheim, 2000, pp. 513Ϫ531.

N. Asano, R. J. Nash, R. J. Molyneux, G. W. J. Fleet, Tetra-

hedron: Asymmetry 2000, 11, 1645Ϫ1680.

C. W. Ekhart, M. H. Fechter, P. Hadwiger, E. Mlaker, A. E.

[8]

Yield: 103 mg (95%). R_fϭ 0.47 (EtOAc/EtOH/H₂O, 45:5:3). [α]²_D²

ϭ

[9]

Ϫ55.6 (c ϭ 1.0, H₂O). UV (MeOH): 241 nm (ε_m 13.9). ¹H NMR

(300 MHz, D₂O, 313 K): δ ϭ 3.64 (t, J_3,4ϭ J_2,3ϭ 8.1 Hz, 1 H, 3-

[10]

H), 3.70 (dd, J_4,5ϭ 1.5, J_3,4ϭ 8.1 Hz, 1 H, 4-H), 3.84 (dd, J_1,2

4.3, J_2,3ϭ 8.1 Hz, 1 H, 2-H), 3.91 (dd, J_1,7bϭ 4.3, J_7a,7bϭ 8.5 Hz,

1 H, 7b-H), 4.17 (d, J_7a,7bϭ 8.5 Hz, 1 H, 7a-H), 4.93 (t, J_1,2

ϭ

[11]

ϭ

Stütz, A. Tauss, T. M. Wrodnigg, in: Imino sugars as Glycosid-

ase Inhibitors (Ed.: A. E. Stütz), Wiley-VCH, Weinheim 1999,

pp. 253Ϫ397.

N. Asano, A. Kato, M. Miyauchi, H. Kizu, T. Tominori, K.

Matsui, R. J. Nash, R. J. Molyneux, Eur. J. Biochem. 1997,

248, 296Ϫ303.

J_1,7bϭ 4.3 Hz, 1 H, 1-H), 5.99 (d, J_4,5ϭ 1.5 Hz, 1 H, 5-H),

7.24Ϫ7.44 (m, 5 H, Ph) ppm. ¹³C NMR (75.5 MHz, D₂O, 313 K):

δ ϭ 58.9 (C-1), 66.4 (C-7), 70.6 (C-2), 73.8 (C-4), 75.0 (C-3), 88.7

(C-5), 127.3Ϫ138.6 (Ph), 178.3 (CS) ppm. FAB-MS: m/z ϭ 319

(100) [M ϩ Na]^ϩ, 297 (60) [M ϩ H]^ϩ. C₁₃H₁₆N₂O₄S (296.34):

calcd. C 52.69, H 5.44, N 9.45; found C 52.32, H 5.42, N 9.37.

[12]

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General Procedure for Inhibition Assay: Inhibitory potencies were

determined by spectrophotometrically measuring the residual hy-

drolytic activities of the glycosidases against the respective o- (for

β-glucosidase/β-galactosidase from bovine liver) or p-nitrophenyl

α- or β--glycopyranoside, sucrose (for invertase) or α,αЈ-trehalose

(for trehalase) in the presence of the corresponding calystegine de-

rivative. Each assay was performed in phosphate buffer or phos-

phate-citrate buffer (for α-mannosidase and amyloglucosidase) at

the optimal pH for each enzyme. The reactions were initiated by

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presence of various concentrations of inhibitor. After the mixture

was incubated for 10Ϫ30 min at 37 °C or 55 °C (for amyloglucosid-

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1819

Article Doi

Synthesis of calystegine B2, B3, and B4 analogues: Mapping the structure-glycosidase inhibitory activity relationships in the 1-deoxy-6-oxacalystegine series

DOI: 10.1002/ejoc.200300731

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Authors:

Article abstract of DOI:10.1002/ejoc.200300731

Full text of DOI:10.1002/ejoc.200300731

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