Synthesis of S-linked thiooligosaccharide analogues of Nod factors: Synthesis of new protected thiodisaccharide and thiotrisaccharide intermediates

Article abstract of DOI:10.1016/S0008-6215(03)00149-6

We are investigating the synthesis of thioanalogues of nodulation factors that will be resistant to degradation by chitinases. To study the influence of our protecting group strategy, the glycosylation of 1,6-anhydro-2-azido-3-O-benzyl-2-deoxy-β-D-glucopyranoside (7) with two trichloroacetimidate glycosyl donors carrying an azido group at C-2 and either benzyl or benzoyl protecting groups on O-3 and O-4 was first attempted under catalysis with BF₃·Et₂O in toluene. While glycosylation with the benzoylated glycosyl donor gave only a poor yield (27%) of the disaccharide, a similar reaction with the benzylated donor gave the corresponding disaccharide in good yield (77%). Although both products were obtained as anomeric mixtures, the benzylated donor led to improved stereoselectivity in favor of the desired β-anomer (α:β 3:7). Based on these results, a novel thiotrisaccharide was synthesized via the coupling of 7 with 6-O-acetyl-4-S-(3,4,6-tri-O-acetyl-2-benzyloxycarbonylamino-2-deoxy-β- D-glucopyranosyl)-2-azido-3-O-benzyl-2-deoxy-4-thio-α-D-glucopyranosyl trichloroacetimidate (25) also newly synthesized. After optimization of the reaction conditions, the desired thiotrisaccharide 4-O-[6-O-acetyl-4-S-(3,4,6-tri-O-acetyl-2-benzyloxycarbonylamino-2-deoxy- β-D-glucopyranosyl)-2-azido-3-O-benzyl-2-deoxy-4-thio-β-D- glucopyranosyl]-1,6-anhydro-2-azido-3-O-benzyl-2-deoxy-β-D- glucopyranoside (26β) was obtained in 57% yield. These conditions led to an anomeric mixture in favor of the desired β-anomer (α:β 1:4.7) that was separated from the α-anomer by normal-phase HPLC on a PrepNova Pack silica gel cartridge. The work described here shows that thiodisaccharide glycosyl donors behave quite differently from the analogous O-disaccharide used previously to synthesize nodulation factors.

Full text of DOI:10.1016/S0008-6215(03)00149-6

Carbohydrate Research 338 (2003) 1369ꢁ1379
/
www.elsevier.com/locate/carres
Synthesis of S-linked thiooligosaccharide analogues of Nod factors:
synthesis of new protected thiodisaccharide and thiotrisaccharide
intermediatesꢀ
Latino Loureiro Morais,a Khalil Bennis,a,* Isabelle Ripoche,a Liang Liao,b
France-Isabelle Auzanneau,b Jacques Gelasa
a
´
Laboratoire de Chimie des He´te´rocycles et des Glucides, Ecole Nationale Supe´rieure de Chimie de Clermont-Ferrand, BP 187, F-63174 Aubie`re, France
b Department of Chemistry and Biochemistry, University of Guelph, Guelph, ON, Canada N1G 2W1
Received 9 December 2002; accepted 6 March 2003
Abstract
We are investigating the synthesis of thioanalogues of nodulation factors that will be resistant to degradation by chitinases. To
study the influence of our protecting group strategy, the glycosylation of 1,6-anhydro-2-azido-3-O-benzyl-2-deoxy-b-
glucopyranoside (7) with two trichloroacetimidate glycosyl donors carrying an azido group at C-2 and either benzyl or benzoyl
protecting groups on O-3 and O-4 was first attempted under catalysis with BF3×Et2O in toluene. While glycosylation with the
D-
/
benzoylated glycosyl donor gave only a poor yield (27%) of the disaccharide, a similar reaction with the benzylated donor gave the
corresponding disaccharide in good yield (77%). Although both products were obtained as anomeric mixtures, the benzylated donor
led to improved stereoselectivity in favor of the desired b-anomer (a:b 3:7). Based on these results, a novel thiotrisaccharide was
synthesized via the coupling of 7 with 6-O-acetyl-4-S-(3,4,6-tri-O-acetyl-2-benzyloxycarbonylamino-2-deoxy-b-
2-azido-3-O-benzyl-2-deoxy-4-thio-a- -glucopyranosyl trichloroacetimidate (25) also newly synthesized. After optimization of the
reaction conditions, the desired thiotrisaccharide 4-O-[6-O-acetyl-4-S-(3,4,6-tri-O-acetyl-2-benzyloxycarbonylamino-2-deoxy-b-
glucopyranosyl)-2-azido-3-O-benzyl-2-deoxy-4-thio-b- -glucopyranosyl]-1,6-anhydro-2-azido-3-O-benzyl-2-deoxy-b- -glucopyra-
D-glucopyranosyl)-
D
D-
D
D
noside (26b) was obtained in 57% yield. These conditions led to an anomeric mixture in favor of the desired b-anomer (a:b 1:4.7) that
was separated from the a-anomer by normal-phase HPLC on a PrepNova Pack† silica gel cartridge. The work described here shows
that thiodisaccharide glycosyl donors behave quite differently from the analogous O-disaccharide used previously to synthesize
nodulation factors.
# 2003 Elsevier Science Ltd. All rights reserved.
Keywords: Nodulation factors; Analogues; Thiooligosaccharides; Glycosylation
1. Introduction
alanine3 by the bacteria residing in root nodules. This
biological process is of considerable interest to agricul-
ture since it could provide an alternative to the use of
fertilizers (e.g., nitrates). The key step of the infection is
the production by the bacteria of extracellular messen-
ger molecules called nodulation factors (Nod factors)
that will induce deformations and nodule organogenesis
on the plant roots.4 Nod factors have been shown2 in all
cases to be lipooligosaccharides constituted of a tetra-
(ABCD) or penta- (ABCDE) saccharidic backbone of
chitin variably substituted as represented on Fig. 1 (1).
Various soil bacteria of the genera Rhizobium, Bradyr-
hizobium or Azorhizobium can enter in a specific
symbiotic association2 with leguminous plants. This
association allows the plant to use atmospheric nitrogen
previously fixed and metabolized into ammonia and
ꢀ Part 3 of a series. For Part 2 see Ref. 1.
* Corresponding author. Tel.: ꢂ
73407008.
E-mail address: bennis@chimtp.univ-bpclermont.fr (K.
Bennis).
/
33-4-73407134; fax: ꢂ33-4-
/
Although only very small concentrations (10ꢀ6ꢁ10ꢀ12
/
mol/L) of Nod factors are required to trigger nodula-
tion, the activity of these oligosaccharides is limited by
0008-6215/03/$ - see front matter # 2003 Elsevier Science Ltd. All rights reserved.
doi:10.1016/S0008-6215(03)00149-6

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L.L. Morais et al. / Carbohydrate Research 338 (2003) 1369ꢁ1379
/
Fig. 1. Natural nodulation factors (1) and thioanalogues of nodulation factors (2).
the action of enzymes named chitinases that cleave the
Bꢁ
C interglycosidic linkage.5 It is known6 that glycosi-
to the trichloroacetimidate glycosyl donor 6. The 1,6-
anhydro bridge was submitted to acetolysis with acetic
anhydride and trifluoroacetic acid to yield an anomeric
mixture of 4 (79%). Selective O-deacetylation at the
anomeric position with hydrazine acetate in N,N-
dimethylformamide led to the hemicetal 5 (82%) that
was converted to the trichloroacetimidate 6 (Cl3CCN/
DBU). The glycosyl donor 6 was obtained in 85% yield
as an anomeric mixture largely in favor of the a-anomer
/
dase enzymes cleave thio-interglycosidic bonds more
slowly than the corresponding oxygen interglycosidic
bonds. Thus, to increase the resistance of our analogues
to chitinases, our research aims at preparing analogues
of Nod factors in which the interglycosidic oxygen atom
between the sugar units B and C is replaced by a sulfur
atom (Fig. 1, 2). We previously reported the synthesis of
various thiodisaccharides by nucleophilic displacement
of a 1,6-anhydrotriflate by an anomeric thiolate7 and, in
turn, described the preparation of a thiotrisaccharide
intermediate.1 We report here the synthesis of new
thiodi- and thiotri-saccharide precursors of larger struc-
tures.
(ꢀ90%) as expected when using 1,8-diazabicy-
/
clo[5.4.0]undec-7-ene (DBU) as a base.9 Glycosylation
of the known10 acceptor 7 with the thiodisaccharide
imidate 6 was then attempted according to the condi-
tions described by Tailler and co-workers8 using BF3×
/
Et2O as a promoter in toluene (Scheme 1). However,
these conditions failed to give the desired trisaccharide.
Similarly, addition of the more active catalyst, triethyl-
silyl trifluoromethanesulfonate, to the reaction mixture
led to the degradation of the glycosyl donor without
formation of the expected trisaccharide. Since the
acceptor 7 had been used successfully10 as a glycosyl
acceptor, we concluded that the protecting group
strategy devised for donor 6 was incompatible with its
coupling to acceptor 7. Thus, we investigated the
reaction of donors 11 and 13 with acceptor 7. The 1,6-
2. Results and discussion
Relying on the results obtained by Tailler and co-
workers,8 our synthetic strategy is based on the use of
2-azido trichloroacetimidate glucosaminyl donors pre-
pared from the thiodisaccharides that we reported
previously.7 To favor the formation of a b-glycosidic
linkage,9 all the trichloroacetimidate glycosyl donors
used in our work were prepared as a-anomers. Thus, the
1,6-anhydro disaccharide 37 was converted in three steps
anhydro-2-azido-2-deoxy-b-
verted to the dibenzoate 8 and then submitted to
D
-glucopyranose10 was con-
Scheme 1. (a) 9:1 Ac2Oꢁ
BF3.Et2O, PhCH3 (no reaction).
/
TFA, 65 8C (79%); (b) H2NNH2×
/AcOH in DMF (82%); (c) Cl3CCN, DBU in CH2Cl2 (85%); (d)

L.L. Morais et al. / Carbohydrate Research 338 (2003) 1369ꢁ
/1379
1371
acetolysis (Ac2Oꢁ
/
TFA) to give diacetate 9 (90%) as an
established previously7 to synthesize N-protected-S-
linked chitobiose derivatives. The gluco derivative 7
anomeric mixture. The anomeric acetyl group in 9 was
selectively removed with hydrazine acetate, and the
hemiacetal 10 was converted to the trichloroacetimidate
11 (Cl3CCN/DBU). Once again, the a:b ratio obtained
was first converted to the triflate 15 (Tf2Oꢁpyridine in
/
dichloromethane), and the triflyl group was subse-
quently displaced with nitrite ions in anhydrous N,N-
dimethylformamide12 to give the nitrite ester that under-
went hydrolysis during workup to afford 16 in 68%
yield. The configurations of the 1,6-anhydro derivatives
15 and 16 were confirmed by 1H NMR coupling
1
for the donor 11 was estimated by H NMR spectro-
scopy to be largely in favor of the a-anomer (ꢀ
/90%).
Similarly, the dibenzylated trichloroacetimidate 13 was
prepared from the corresponding hemiacetal.11 Glyco-
sylation of acceptor 7 with donors 11 and 13 (Scheme 2)
was then attempted using the reaction conditions that
had previously failed to promote its coupling to imidate
constants measured between H-3 and H-4 (Â1 and
/
5.5 Hz, respectively, for the gluco and galacto config-
urations). The galacto derivative 16 was then treated
with triflic anhydride to give the triflate derivative 17 in
94% yield, which was ready to undergo nucleophilic
displacement with the thiol 21. Thus, the known13
hemiacetal 18 was treated with acetyl chloride to give
in one step the acetylated glucosyl chloride 19,14 which
was immediately converted (thiourea, acetone) to the
pseudothiourea hydrochloride 20 following the proce-
dure of Horton and Wolfrom.15 Finally, treatment of 20
with sodium sulfite in a mixture of acetone and water led
efficiently to the corresponding anomeric thiol 21 (81%).
Reaction of thiol 21 with sodium hydride led to the
corresponding thiolate, which was in turn condensed
with the triflate derivative 17 to afford the thiodisac-
charide 22 in excellent yield (88%). Conversion of the
1,6-anhydro thiodisaccharide 22 to the glycosyl donor
6 (BF3×/Et2O in toluene). Thus, glycosylation of excess
(1.3 equiv) 7 with the benzoylated glycosyl donor 11
gave only a poor yield (27%) of disaccharide 12 that was
isolated as an anomeric mixture only slightly in favor of
the b-anomer (a:b 4:6). In contrast, coupling of 7 with
the benzylated analogue 13 gave disaccharide 14 in good
yield (77%) and with an improved stereoselectivity
towards the b-anomer (a:b 3:7). Although this selectivity
was not as pronounced as expected when using trichlor-
oacetimidate glycosyl donors bearing nonparticipating
groups at C-2,9,10 the yield obtained with the benzylated
donor 13 prompted us to investigate the efficiency of the
thiodisaccharide 25 as a glycosyl donor to prepare
thiotrisaccharide 26 (Scheme 3). Therefore, we prepared
thiodisaccharide 22 following the strategy that we
Scheme 2. (a) 9:1 Ac2Oꢁ
/
TFA, 20 8C (90%); (b) H2NNH2×
/
AcOH in DMF (83%); (c) Cl3CCN, DBU in CH2Cl2 (31%); (d)
BF3.Et2O, PhCH3, ꢀ50 8C, 1.3 equiv of 7 [27% for 12 (a:b 4:6), 77% for 14 (a:b 3:7)].
/

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L.L. Morais et al. / Carbohydrate Research 338 (2003) 1369ꢁ1379
/
25 was then accomplished in three steps: opening of the
1,6-anhydro ring (TFAꢁAc2O), O-deacetylation at the
anomeric position (hydrazine acetate) and reaction with
trichloroacetonitrile in the presence of DBU (Scheme 3).
Thus, trichloroacetimidate 25 was obtained from the
hemiacetal 24 in 82% yield and as an anomeric mixture
largely in favor of the a-anomer (a:b 8:2) as established
from its H NMR spectrum.
Glycosidation of donor 25 with 2 molar equiv of
1
/
alcohol 7 was then attempted under BF3×
/
Et2O catalysis
in toluene using the conditions (Table 1, Entry 1) that
were successful for the synthesis of the model disacchar-
Scheme 3. (a) Tf2O, C6H5Nꢁ
CH2Cl2, ꢀ15 8C (94%); (d) AcCl; (e) H2NCSNH2, acetone [47% over (d) and (e)]; (f) Na2SO3, acetoneꢁ
21 in DMF at 0 8C then 17 at 20 8C (88%); (h) 9:1 Ac2Oꢁ
/
CH2Cl2, ꢀ
/
15 8C (quant); (b) NaNO2, DMF, 20 8C then aqueous workup (68%); (c) Tf2O in C6H5Nꢁ
water (81%); (g) NaH with
AcOH in DMF (81%, a:b 6:4);
/
/
/
/
TFA, 20 8C (96%, a:b 75:25); (i) H2NNH2×
/
(j) Cl3CCN, DBU in CH2Cl2 (82%, a:b 8:2); (k) see Table 1 for details.
Table 1
Glycosidation of thiodisaccharide trichloroacetimidate glycosyl donor 25 by alcohol 7
Entry
Catalyst
Solvent
Temperature (8C)
Yield (%)
a/b ratio
1
2
3
4
BF3×Et2O
TESOTf
TESOTf
/
PhCH3
PhCH3
CH3CN
CH2Cl2
ꢀ
/
78ꢁ
78ꢁ
30ꢁ
78ꢁ
/
ꢀ
/
20
20
10
20
24
20
29
57
3:1
2:1
ꢀ
/
/
ꢀ
/
ꢀ
/
/
ꢀ
/
1:2
1:4.7
BF3×/Et2O
ꢀ
/
/
ꢀ
/

L.L. Morais et al. / Carbohydrate Research 338 (2003) 1369ꢁ
/1379
1373
ide 14. However, the results were in contrast with those
obtained for the preparation of 14 since only 24% of the
trisaccharide 26 was isolated after chromatography. In
addition, careful examination of the 1H NMR spectrum
showed that 26 was obtained as an anomeric mixture in
which, surprisingly, the a-anomer was the major pro-
duct formed (a:b 3:1). As can be seen from Table 1,
charide 26b could be prepared in sufficient amount to
allow investigation towards extension at the reducing
end. Thus, it is now undergoing further studies to
provide access to the first thiotetrasaccharide analogue
of nodulation factor.
replacing BF3×/Et2O with triethylsilyl triflate in toluene
3. Experimental
or acetonitrile did not increase the yield of thiotrisac-
charide 26. However, these conditions gave a better
3.1. General methods
selectivity in favor of the b-anomer than BF3×
/
Et2O (in
toluene): the ratio a:b decreased to 2:1 in toluene (Entry
2) and to 1:2 in acetonitrile (Entry 3). Finally, to favor
an SN2 displacement of the trichloroacetimidate group
in 25, we attempted to use the less polar solvent
Melting points were determined with a Buchi B-450
¨
apparatus and are uncorrected. Optical rotations were
measured with a JASCO DIP-370 digital polarimeter.
1H (400 MHz) and 13C NMR (100 MHz) spectra were
recorded with a Bruker AC 400 NMR or an Avance 400
NMR for solutions in CDCl3, (CD3)2SO or CD3OD
(internal standard, for 1H: residual CHCl3 dH 7.27 ppm,
Me2SO dH 2.49 ppm or MeOH dH 3.31 ppm, for 13C:
CDCl3 dC 77.0). First-order chemical shifts and cou-
pling constants (J Hz) were obtained from one-dimen-
sional spectra. Assignments of proton and carbon
dichloromethane under catalysis with BF3×/Et2O (Table
1, Entry 4). These conditions turned out to be successful
since thiotrisaccharide 26 was isolated in 57% yield
based on the imidate 25, which was used as the limiting
reagent. Most importantly, these conditions led to an
anomeric mixture considerably in favor of the wanted b-
anomer (a:b 1:4.7). The two anomers, which could not
be separated by conventional chromatography using
various solvent systems and column sizes, were even-
tually obtained pure by normal-phase HPLC on a
PrepNova Pack† silica gel cartridge (Waters) using a
mixture of ethyl acetate and hexane as the mobile phase.
The formation of b-glycosidic linkages of glucosamine
typically relies on the use of donors carrying participat-
ing groups such as phthalimide or alkylcarbamates at C-
2.16,17 However, these glycosyl donors have limited
reactivity especially when coupled to poorly reactive
acceptors such as the 4-hydroxyl group of a glucosamine
acceptor. To circumvent these limitations, alternative
synthetic strategies have used 2-azido-a-trichloroaceti-
midates9,10 and a-phosphates as glycosyl donors.18
While a-trichloroacetimidates were reported to give b-
anomers with very good selectivity,9,10 a-phosphates
were reported to give a 1:4 mixture of a and b-
anomers.18 In fact, the synthesis of nodulation factors
through coupling of 2-azido trichloroacetimidate gluco-
samine glycosyl donors to the known acceptor 7 were
reported10 to give b-glycosidic linkages in good yields
and with high stereoselectivity. In contrast, our results
show that this synthetic strategy applied to the coupling
of the 2-azido trichloroacetimidate thiodisaccharide
glycosyl donor 25 to acceptor 7 was less selective in
favor of a b-glycosidic linkage. Based on the results
described here, we conclude that thiodisaccharide tri-
chloroacetimidate glycosyl donors (like 25) behave quite
differently from the analogous O-disaccharides used
previously extensively and successfully to synthesize10
nodulation factors. In fact, our results are similar to
those obtained when coupling a 2-azido a-phosphate
glycosyl donor to the more reactive 2-OH and 6-OH
groups of glucose acceptors.18 However, the thiotrisac-
resonances were based on COSY and 13Cꢁ1
H hetero-
/
nuclear correlated experiments. TLC was performed on
precoated aluminium plates with Silica Gel 60 F254 (E.
Merck), and products were detected with UV light and/
or by charring with 10% H2SO4 solution in EtOH.
Solvents were distilled and dried according to standard
procedures,19 and organic solutions were dried over
Na2SO4 and concentrated below 40 8C under reduced
pressure. Compounds were purified by atmospheric
pressure chromatography with Silica Gel (70ꢁ
/120)
mesh or neutral aluminium oxide (50ꢁ200 mm). Ele-
/
mental analyses were performed at the ‘Service Central
d’Analyses du CNRS’, Lyon. High-resolution mass
spectrometry analyses were performed at the ‘Centre
Re´gional de Mesures Physiques de l’Ouest’, Rennes.
3.2. 4-S-(2-Acetamido-3,4,6-tri-O-acetyl-2-deoxy-b-
glucopyranosyl)-1,6-di-O-acetyl-2-azido-3-O-benzoyl-2-
deoxy-4-thio-a,b- -glucopyranoside (4)
D-
D
Anhydro 37 (250 mg, 0.636 mmol) was dissolved in 9:1
Ac2OꢁTFA (30 mL), and the solution was stirred for 14
/
h at room temperature (rt) and for 6 h at 65 8C. Solvents
were evaporated, and residual traces of acid were co-
evaporated with toluene. Chromatography (hexaneꢁ
/
EtOAc, gradient 1:2 to 1:6, followed by EtOAc) of the
dry residue gave the anomeric mixture of diacetate 4
(200 mg, 79%); 1H NMR in CDCl3 showed a ratio a:b of
55:45; 1H NMR (CDCl3): d 8.09 (m, 2 Ha, 2 Hb,
aromatics), 7.55 (m, 1 Ha, 1 Hb, aromatic), 7.50 (m, 2
Ha, 2 Hb, aromatics), 6.40 (d, 1 Ha, J1,2 3.5 Hz, H-1Ba),
5.71 (t, 1 Ha, J2,3ꢂ3,4 20.6 Hz, H-3Ba), 5.65 (d, 1 Ha,
JNH,2 9.8 Hz, NHAa), 5.58 (d, 1 Hb, J1,2 8.8 Hz, H-
1Bb), 5.53 (d, 1 Hb, JNH,2 9.8 Hz, NHAb), 5.32 (t, 1 Hb,

1374
L.L. Morais et al. / Carbohydrate Research 338 (2003) 1369ꢁ1379
/
J2,3ꢂ3,4 20.6 Hz, H-3Bb), 5.16 (t, 1 Ha, J2,3ꢂ3,4 19.2 Hz,
H-3Aa), 5.09 (t, 1 Hb, J2,3ꢂ3,4 19.7 Hz, H-3Ab), 5.01ꢁ
4.94 (m, 1 Ha, 1 Hb, H-4Aa, H-4Ab), 4.91 (d, 1 Ha, J1,2
10.3 Hz, H-1Aa), 4.87 (d, 1 Hb, J1,2 10.8 Hz, H-1Ab),
3.4. 4-S-(2-Acetamido-3,4,6-tri-O-acetyl-2-deoxy-b-
glucopyranosyl)-6-O-acetyl-2-azido-3-O-benzoyl-2-
deoxy-4-thio-a,b-D-glucopyranosyl trichloroacetimidate
D-
/
(6)
4.64ꢁ
Hb, H-6Bb), 4.46ꢁ
/
4.55 (m, 1 Ha, 1 Hb, H-6?Ba, H-6?Bb), 4.50 (m, 1
Trichloroacetonitrile (1 mL, 10 mmol) and DBU (20 mL,
0.134 mmol) were added to a solution of the hemiacetal
5 (350 mg, 0.502 mmol) in anhyd CH2Cl2 (12 mL), and
the reaction mixture was stirred for 2 h under Ar at rt.
Solvents were evaporated off, and the residue was
/
4.38 (m, 2 Ha, H-5Ba, H-6Ba), 4.29ꢁ
/
4.13 (m, 2 Ha, 3 Hb, H-6Aa, H-6Ab, H-2Aa, H-2Ab,
H-5Bb), 4.04 (dd, 1 Ha, J5,6? 7.4, J6,6? 12.3 Hz, H-6?Aa),
3.96 (dd, 1 Hb, J5,6? 7.4 Hz, J6,6? 12.3 Hz, H-6?Ab), 3.90ꢁ
/
3.70 (m, 2 Ha, 2 Hb, H-2Ba, H-2Bb, H-5Aa, H-5Ab),
3.13 (dd, 1 Ha, J3,4ꢂ4,5 21.2 Hz, H-4Ba), 3.05 (dd, 1 Hb,
J3,4ꢂ4,5 21.6 Hz, H-4Bb) 2.25 (s, 3 Ha, CH3COa), 2.20
(s, 3 Hb, CH3COb), 2.25 (s, 3 Hb, CH3COb), 2.09 (s, 3
purified by chromatography (7:3 tolueneꢁEtOAc) to
/
1
give the imidate 6 (360 mg, 85%) as a glass; H NMR
spectroscopy in CDCl3 showed the a-anomer to be in
1
large majority (90%); H NMR (CDCl3) for a-anomer:
Ha, CH3COa), 2.08 (s, 3 Hb, CH3COb), 2.07ꢁ
Ha, 6 Hb, 3ꢃ CH3COa, 2ꢃ CH3COb), 2.01 (s, 3 Ha,
CH3COa), 2.00 (s, 3 Hb, CH3COb). HRMS Calcd for
C31H38N4O15S [Mꢂ
Na]ꢂ: 761.1952. Found: 761.1948.
/
2.03 (m, 9
d 8.84 (s, 1 H, NHB), 8.07 (m, 2 H, aromatics), 7.65 (m,
1 H, aromatic), 7.50 (m, 2 H, aromatics), 6.59 (d, 1 H,
J1,2 3.5 Hz, H-1B), 5.81 (dd, 1 H, J2,3 10.3 Hz, J3,4 10.8
/
/
/
Hz, H-3B), 5.67 (d, 1 H, JNH,2 9.8 Hz, NHA), 5.12ꢁ
(m, 2 H, H-3A, H-4A), 4.89 (d, 1 H, J1,2 10.7 Hz, H-1A),
4.65 (dd, 1 H, J5,6 2.9 Hz, J6,6? 11.8 Hz, H-6B), 4.55ꢁ
4.45 (m, 2 H, H-5B, H-6?B), 4.25ꢁ4.19 (m, 1 H, H-2A),
4.13ꢁ3.95 (m, 3 H, H-2B, H-6A, H-6?A), 3.65ꢁ3.57 (m,
1 H, H-5A), 3.19 (t, 1 H, J 10.8 Hz, H-4B), 2.08, 2.05,
2.04 and 2.00 (4 s, 15 H, 5ꢃ CH3CO).
/5.02
/
3.3. 4-S-(2-Acetamido-3,4,6-tri-O-acetyl-2-deoxy-b-
glucopyranosyl)-6-O-acetyl-2-azido-3-O-benzoyl-2-
deoxy-4-thio-a,b-D-glucopyranose (5)
D-
/
/
/
/
Hydrazine acetate (74 mg, 0.803 mmol) was added to a
solution of the diacetate 4 (489 mg, 0.661 mmol) in
DMF (6 mL). The reaction mixture was stirred for 1 h at
rt and diluted with EtOAc (25 mL). The solution was
3.5. Preparation of 1,6-anhydro-2-azido-3,4-di-O-
benzoyl-2-deoxy-b- -glucopyranose (8)
D
Benzoyl chloride (845 mL, 7.28 mmol) was added to a
-glucopyr-
anose (400 mg, 2.14 mmol)10 in anhyd pyridine (7 mL).
The reaction mixture was stirred for 2 h at rt. Methanol
(10 mL) was added to the mixture, solvents were
evaporated, and the residue dissolved in CH2Cl2 (20
washed successively with brine (2ꢃ
(2ꢃ15 mL). The washings were re-extracted with
EtOAc (2ꢃ15 mL), and the combined organic extracts
were dried and concentrated. Chromatography of the
residue (1:1, then 2:3 and 3:7 tolueneꢁEtOAc) afforded
/
15 mL) and water
solution of 1,6-anhydro-2-azido-2-deoxy-b-
D
/
/
/
the anomeric mixture of the hemiacetal 5 (377 mg, 82%);
1
mL) was washed with 1 M HCl (2ꢃ
NaHCO3 (2ꢃ15 mL) and water (2ꢃ
washings were re-extracted with CH2Cl2 (2ꢃ
/
15 mL), satd aq
15 mL). The
15 mL)
1H NMR in CDCl3 showed a ratio a:b of 75:25; H
/
/
NMR (CDCl3): d 8.15 (m, 2 Ha, 2 Hb, aromatics), 7.65
(m, 1 Ha, 1 Hb, aromatic), 7.50 (m, 2 Ha, 2 Hb,
aromatics), 5.82 (dd, 1 Ha, J2,3ꢂ3,4 21.2 Hz, H-3Ba),
5.68 (d, 1 Ha, JNH,2 9.8 Hz, NHAa), 5.57 (d, 1 Hb, JNH,2
9.8 Hz, NHAb), 5.48 (d, 1 Ha, J1,2 2.9 Hz, H-1Ba), 5.24
/
and the combined organic extracts were dried and
concentrated. Chromatography (7:1 then 4:1 cy-
clohexaneꢁ
8 (738 mg, 87%) as white crystals: mp 109 8C, lit.1 108ꢁ
109 8C; 1H NMR (CDCl3): d 7.45ꢁ
7.30 (m, 10 H,
/
EtOAc) of the residue gave the dibenzoate
/
(dd, 1 Hb, J2,3 9.8 Hz, J3,4 10.8 Hz, H-3Bb), 5.14ꢁ
/
4.99
/
(m, 2 Ha, 2 Hb, H-3Aa, H-3Ab, H-4Aa, H-4Ab), 4.96
(d, 1 Ha, J1,2 10.8 Hz, H-1Aa), 4.89 (d, 1 Hb, J1,2 10.3
aromatics), 5.66 (br s, 1 H, H-3), 5.37 (m, 1 H, H-4),
5.11 (br s, 1 H, H-1), 4.87 (br d, 1 H, H-5), 4.36 (d, 1 H,
J6,6? 8 Hz, H-6?), 3.98 (dd, 1 H, J5,6 5.8 Hz, H-6), 3.48 (br
s, 1 H, H-2).
Hz, H-1Ab), 4.78 (d, 1 Hb, J1,2 7.9 Hz, H-1Bb), 4.65ꢁ
4.47 (m, 3 Ha, 2 Hb, H-5Ba, H-6Ba, H-6Bb, H-6?Ba, H-
6?Bb), 4.25ꢁ4.15 (m, 2 Ha, 2 Hb, H-2Aa, H-2Ab, H-
6?Aa, H-6?Ab), 4.05ꢁ3.98 (m, 1 Ha, 2 Hb, H-5Bb, H-
6Aa, H-6Ab), 3.80ꢁ3.71 (m, 1 Ha, 1 Hb, H-5Aa, H-
5Ab), 3.68ꢁ3.60 (m, 1 Ha, 1 Hb, H-2Ba, H-2Bb), 3.05
/
/
/
3.6. 1,6-Di-O-acetyl-2-azido-3,4-di-O-benzoyl-2-deoxy-
a,b-D-glucopyranose (9)
/
/
(t, 1 Ha, J 10.8 Hz, H-4Ba), 3.02 (t, 1 Hb, J 10.8 Hz, H-
4Bb), 2.11 (s, 3 Ha, CH3COa), 2.10 (s, 3 Ha, 3 Hb,
CH3COa, CH3COb), 2.08 (s, 3 Hb, CH3COb), 2.05 (m,
Anhydro 8 (700 mg, 1.77 mmol) was dissolved in 4.6:1
Ac2OꢁTFA (49.2 mL), and the solution was stirred for 6
h at rt. Solvents were evaporated, and residual traces of
/
6 Ha, 6 Hb, 2ꢃ
Ha, 3Hb, CH3COa, CH3COb). HRMS Calcd for
C29H36N4O14S [Mꢂ
Na]ꢂ: 719.1846. Found: 719.1842.
/
CH3COa, 2ꢃ CH3COb), 2.00 (2 s, 3
/
acid were co-evaporated with toluene. Chromatography
(7:1, 5:1, 3:1 and 1:1 cyclohexaneꢁ
/
EtOAc) of the dry
residue gave an anomeric mixture of diacetate 9 (790
/

L.L. Morais et al. / Carbohydrate Research 338 (2003) 1369ꢁ
/1379
1375
mg, 90%); 1H NMR in CDCl3 showed a ratio a:b of 8:2;
1H NMR (CDCl3): d 8.00ꢁ
7.85 (m, 4 Ha, 4 Hb,
aromatics), 7.55ꢁ7.50 (m, 2 Ha, 2 Hb, aromatics),
7.45ꢁ7.35 (m, 4 Ha, 4 Hb, aromatics), 6.45 (d, 1 Ha,
J1,2 3.6 Hz, H-1a), 5.94 (dd, 1 Ha, J2,3ꢂ3,4 or J3,4ꢂ4,5
20.1 Hz, H-3a or H-4a), 5.75 (d, 1 Hb, J1,2 8.4 Hz, H-
showed the a-anomer to be the major anomer (90%); 1H
NMR (CDCl3) for a-anomer: d 8.90 (s, 1 H, NH), 8.00ꢁ
7.40 (m, 10 H, aromatics), 6.64 (d, 1 H, J1,2 3.9 Hz, H-1),
6.01 (t, 1 H, J2,3ꢂ3,4 or J3,4ꢂ4,5 19.7 Hz, H-3 or H-4),
5.62 (t, 1 H, J2,3ꢂ3,4 or J3,4ꢂ4,5 19.8 Hz, H-3 or H-4),
4.44 (m, 1 H, H-5), 4.25 (m, 2 H, H-6, H-6?), 3.95 (dd, 1
H, J2,3 10.8 Hz, H-2), 2.02 (s, 3 H, CH3CO).
/
/
/
/
1b), 5.61ꢁ
/
5.48 (m, 1 Ha, 2 Hb, H-3a or H-4a, H-3b, H-
4b), 4.32ꢁ
/
4.14 (m, 3 Ha, 2 Hb, H-5a, H-6a, H-6?a, H-
6b, H-6?b), 4.04 (m, 1 Hb, H-5b), 3.90 (dd, 1 Hb, J2,3 9.7
Hz, H-2b), 3.83 (dd, 1 Ha, J2,3 10.5 Hz, H-2a), 2.30 (s, 3
Ha, CH3COa), 2.25 (s, 3 Hb, CH3COb), 2.10 (s, 3 Ha, 3
Hb, CH3COa, CH3COb). HRMS Calcd for
3.9. 4-O-(6-O-Acetyl-2-azido-3,4-di-O-benzoyl-2-deoxy-
a,b-
2-deoxy-b-
D
-glucopyranosyl)-1,6-anhydro-2-azido-3-O-benzyl-
D-glucopyranoside (12)
C24H23N3O9 [Mꢂ
Na]ꢂ: 520.1332. Found: 520.1330.
/
A suspension of the alcohol 7 (120 mg, 0.434 mmol) and
the imidate 11 (186 mg, 0.310 mmol) in dry toluene (10
˚
mL) containing 4 A activated molecular sieves (450 mg)
was stirred under Ar at rt for 30 min. The reaction
3.7. 6-O-Acetyl-2-azido-3,4-di-O-benzoyl-2-deoxy-a,b-
-glucopyranose (10)
D
mixture was cooled to ꢀ
/
50 8C, and a solution of BF3×
/
Hydrazine acetate (164 mg, 1.79 mmol) was added to a
solution of the diacetate 9 (740 mg, 1.49 mmol) in DMF
(10 mL). The reaction mixture was stirred for 2 h at rt,
and additional hydrazine acetate (42 mg, 0.456 mmol)
was added. The mixture was stirred for 1 h at rt and
diluted with EtOAc (40 mL), and the solution was
Et2O in CH2Cl2 (0.16 M, 196 mL, 0.031 mmol) was
added. The reaction was monitored by TLC (2:1
cyclohexaneꢁ
/
AcOEt) and more BF3×
/
Et2O in CH2Cl2
(0.16 M, 300 mL and 196 mL, 0.077 mmol) was added
portionwise over 6 h. Triethylamine (100 mL) was added,
and the reaction mixture was stirred for 14 h at rt. The
molecular sieves were decanted and washed with
CH2Cl2. The supernatant and washings were combined,
diluted with CH2Cl2 (40 mL) and washed with water
washed successively with brine (2ꢃ
(2ꢃ20 mL). The washings were re-extracted with
EtOAc (2ꢃ20 mL), and the combined organic extracts
were dried and concentrated. Chromatography of the
residue (1:1, then 2:3 and 3:7 tolueneꢁEtOAc) gave an
/20 mL) and water
/
/
(2ꢃ
trated, and the residue was purified by chromatography
(7:1, 5:1 then 4:1 tolueneꢁEtOAc) to give an anomeric
/30 mL). The organic layer was dried and concen-
/
anomeric mixture of the hemiacetal 10 (560 mg, 83%);
1H NMR in CDCl3 showed a ratio a:b of 7:3; 1H NMR
/
1
mixture of disaccharide 12 (60 mg, 27%) as a glass; H
1
(CDCl3): d 8.00ꢁ
/
7.85 (m, 4 Ha, 4 Hb, aromatics), 7.55
NMR in CDCl3 showed a ratio a:b of 4:6; H NMR
(m, 2 Ha, 2 Hb, aromatics), 7.38 (m, 4 Ha, 4 Hb,
aromatics), 6.02 (dd, 1 Ha, J3,4 10.1 Hz, J4,5 9.5 Hz, H-
(CDCl3): d 7.99ꢁ
7.48 (m, 2 Ha, 2 Hb, aromatics), 7.44ꢁ7.32 (m, 9 Ha, 9
/
7.87 (m, 4 Ha, 4 Hb, aromatics), 7.56ꢁ
/
/
4a), 5.55ꢁ
4b), 4.95 (d, 1 Hb, J1,2 7.7 Hz, H-1b), 4.52 (m, 1 Ha, H-
5a), 4.30ꢁ4.20 (m, 2 Ha, 2-Hb, H-6a, H-6?a, H-6b, H-
/
5.48 (m, 2 Ha, 2 Hb, H-1a, H-3a, H-3b, H-
Hb, aromatics), 6.09 (dd, 1 Ha, J2,3 10.8 Hz, J3,4 9.2 Hz,
H-3Aa), 5.65 (br s, 1 Ha, H-1Ba), 5.55 (br s, 1 Hb, H-
/
1Bb), 5.53ꢁ
4Ab), 5.14 (d, 1 Ha, J1,2 3.7 Hz, H-1Aa), 4.99 (m, 1 Ha,
H-5Ba), 4.80ꢁ4.72 (m, 1 Ha, 2 Hb, CHPha, CHPhb, H-
5Bb), 4.70ꢁ4.58 (m, 2 Ha, 2 Hb, CHPha, CHPhb, H-
1Ab, H-5Aa), 4.30 (dd, 1 Ha, J5,6 2.6 Hz, J6,6? 12.3 Hz,
H-6Aa), 4.25ꢁ4.12 (m, 2 Ha, 3 Hb, H-6Ab, H-6?Aa, H-
6?Ab, H-6Ba, H-6Bb), 4.03 (br s, 1 Hb, H-4Bb), 3.93 (br
s, 1 Ha, H-4Ba), 3.88ꢁ3.73 (m, 1 Ha, 4 Hb, H-3Bb, H-
/
5.42 (m, 1 Ha, 2 Hb, H-3Ab, H-4Aa, H-
6?b), 3.95 (m, 1 Hb, H-5b), 3.72 (dd, 1 Hb, J2,3 10.2 Hz,
H-2b), 3.58 (dd, 1 Ha, J1,2 3.2 Hz, J2,3 10.5 Hz, H-2a),
2.09 and 2.05 (2 s, 3 Ha, 3 Hb, CH3COa, CH3COb).
/
/
HRMS Calcd for C22H21N3O8 [Mꢂ
/
Na]ꢂ: 478.1226.
Found: 478.1232.
/
/
3.8. 6-O-Acetyl-2-azido-3,4-di-O-benzoyl-2-deoxy-a,b-
-glucopyranosyl trichloroacetimidate (11)
2Ab, H-5Ab, H-6?Ba, H-6?Bb), 3.68 (br s, 1 Ha, H-3Ba),
3.44 (dd, 1 Ha, H-2Aa), 3.28 (br s, 1 Hb, H-2Bb), 3.18
(br s, 1 Ha, H-2Ba), 2.07 (s, 3 Ha, CH3COa), 1.97 (s, 3
D
Trichloroacetonitrile (2.29 mL, 22.85 mmol) and a
solution of DBU in CH2Cl2 (0.67 M, 494 mL, 0.296
mmol) were added to a solution of the hemiacetal 10
(520 mg, 1.14 mmol) in anhyd CH2Cl2 (15 mL), and the
reaction mixture was stirred for 1 h under Ar at rt. After
concentration, the residue was purified by chromato-
graphy on silica gel packed with NEt3-containing
Hb, CH3COb). HRMS Calcd for C35H34N6O11 [Mꢂ
/
Na]ꢂ: 737.2183. Found: 737.2186.
3.10. 6-O-Acetyl-2-azido-3,4-di-O-benzyl-2-deoxy-a,b-
D
-glucopyranosyl trichloroacetimidate (13)
solvent and eluted with a gradient of cyclohexaneꢁ
EtOAc (7:1, 5:1 then 3:1) to give the imidate 11 (213
1
mg, 31%) as a glass; H NMR spectroscopy in CDCl3
/
Reaction
deoxy-a,b-
of
6-O-acetyl-2-azido-3,4-di-O-benzyl-2-
D
-glucopyranose (545 mg, 1.28 mmol)11
with trichloroacetonitrile (2.56 mL, 25.5 mmol) and

1376
L.L. Morais et al. / Carbohydrate Research 338 (2003) 1369ꢁ1379
/
DBU (solution in CH2Cl2, 0.67 M, 442 mL, 0.333 mmol),
as well as work-up of the reaction and purification by
chromatography, were carried out using the same
conditions than those described above for the prepara-
tion of imidate 11. The imidate 13 (670 mg, 83%) was
in CH2Cl2 (15 mL) cooled at ꢀ
/
15 8C, and the reaction
mixture was stirred at ꢀ15 8C for 1 h. The solution was
/
warmed to 20 8C, diluted with CH2Cl2 (100 mL) and
washed successively with 5% HCl, satd aq NaHCO3 and
water. The aq layers were re-extracted with CH2Cl2 (50
mL), and the combined organic layers were dried and
1
obtained pure as a glass, and H NMR spectroscopy in
CDCl3 showed the a-anomer to be formed in large
concentrated to give the triflate 15 (3.78 g, quant.); [a]D22
1
1
majority (ꢀ
/
95%); H NMR (CDCl3) for a-anomer: d
ꢂ
/
258 (c 0.99, CHCl3); H NMR (CDCl3): d 7.45ꢁ
/7.30
8.76 (s, 1 H, NHCCl3), 7.44ꢁ
6.42 (d, 1 H, J1,2 3.8 Hz, H-1), 4.96 (s, 2 H, CH2Ph), 4.89
(m, 1 H, CHPh), 4.61 (m, 1 H, CHPh), 4.33ꢁ4.24 (m, 2
/
7.28 (m, 10 H, aromatics),
(m, 5 H, aromatics), 5.57 (br s, 1 H, H-1), 4.81 (br s, 1 H,
H-4), 4.76 (d, 1 H, J5,6? 5.9 Hz, H-5), 4.69 (br s, 2 H,
CH2Ph), 4.19 (d, 1 H, J6,6? 8.2 Hz, H-6), 3.85 (dd, 1H, H-
6?), 3.77 (br s, 1 H, H-3), 3.37 (br s, 1 H, H-2). Anal.
Calcd for C14H14F3N3O6S: C, 41.08; H, 3.45; N, 10.27.
Found: C, 41.25; H, 3.48; N, 10.21.
/
H, H-6, H-6?), 4.05 (m, 2 H, H-3 or H-4, H-5), 3.70 (m, 2
H, H-2, H-3 or H-4), 2.05 (s, 3 H, CH3CO).
3.11. 4-O-(6-O-Acetyl-2-azido-3,4-di-O-benzyl-2-deoxy-
a,b-
2-deoxy-b-
D
-glucopyranosyl)-1,6-anhydro-2-azido-3-O-benzyl-
3.13. 1,6-Anhydro-2-azido-3-O-benzyl-2-deoxy-b-D-
galactopyranoside (16)
D-glucopyranoside (14)
A suspension of alcohol 7 (240 mg, 0.864 mmol) and
imidate 13 (380 mg, 0.665 mmol) in dry toluene (15 mL)
˚
containing 4 A activated molecular sieves (650 mg) was
treated as described for synthesis of the compound 12
Triflate 15 (3.78 g, 9.24 mmol) was dissolved in anhyd
DMF (30 mL) containing NaNO2 (6.38 g, 92.4 mmol).
The reaction mixture was stirred at 20 8C for 20 h, the
DMF was removed under reduced pressure, and the
residual solvent was co-evaporated with toluene. The
residue was diluted with CH2Cl2 (100 mL) and washed
successively with brine and water. The aqueous layers
using 0.1 equiv of BF3×
M, 421 mL). The residue was purified by column
chromatography (7:1, 5:1 then 4:1 tolueneꢁAcOEt) to
/
Et2O (solution in CH2Cl2, 0.16
/
1
afford the disaccharide 14 (350 mg, 77%) as a glass; H
1
were re-extracted with CH2Cl2 (2ꢃ
/
50 mL), and the
combined organic layers were dried and concentrated.
NMR in CDCl3 showed a ratio a:b of 3:7; H NMR
(CDCl3): d 7.40ꢁ
/
7.25 (m, 15 Ha, 15 Hb, aromatics),
Chromatography (98:2 CHCl3ꢁEtOAc) of the residue
/
5.56 (br s, 1 Ha, H-1Ba), 5.50 (br s, 1 Hb, H-1Bb), 4.93
(d, 1 Ha, 1 Hb, J 10.7 Hz, CHPha, CHPhb), 4.89ꢁ4.84
(m, 3 Ha, 1 Hb, 2ꢃ CHPha, CHPhb, H-1Aa), 4.82 (d,
1 Hb, J 10.7 Hz, CHPhb), 4.77 (m, 1 Ha, H-5Ba), 4.74ꢁ
gave the alcohol 16 (1.75 g, 68%) as a glass; [a]D22
ꢂ288 (c
/
1
/
1.1, CHCl3); H NMR (CDCl3): d 7.45ꢁ
/
7.30 (m, 5 H,
/
aromatics), 5.45 (br s, 1 H, H-1), 4.75 (d, 1 H, J 11.3 Hz,
CHPh), 4.53 (d, 1 H, J 11.3 Hz, CHPh), 4.45 (m, 1 H,
H-5), 4.25 (d, 1 H, J6,6? 7.5 Hz, H-6), 4.04 (m, 1 H, H-4),
3.85 (d, 1 H, J3,4 5.4 Hz, H-3), 3.68 (dd, 1 H, J5,6? 6 Hz,
H-6?), 3.53 (br s, 1 H, H-2), 3.05 (d, 1 H, J4,OH 9.6 Hz,
OH). Anal. Calcd for C13H15N3O4: C, 56.31; H, 5.45; N,
15.15. Found: C, 56.25; H, 5.39; N, 14.99.
/
4.69 (m, 1 Ha, 2 Hb, CHPha, CHPhb, H-5Bb), 4.62 (d,
1 Ha, 1 Hb, J 10.7 Hz, CHPha, CHPhb), 4.59 (d, 1Ha,
1 Hb, J 10.7 Hz, CHPha, CHPhb), 4.36 (d, 1 Hb, J1,2
Hz, H-1Ab), 4.35ꢁ4.28 (m, 1 Ha, 1 Hb, H-6Aa, H-
6Ab), 4.21ꢁ4.06 (m, 4 Ha, 2 Hb, H-3Aa, H-5Aa, H-
6?Aa, H-6?Ab, H-6Ba, H-6Bb), 3.97 (br s, 1 Hb, H-4Bb),
3.83ꢁ3.77 (m, 2 Ha, 1 Hb, H-6?Ba, H-6?Bb, H-3Ba),
3.75 (br s, 1 Hb, H-3Bb), 3.58ꢁ3.49 (m, 2 Ha, 2 Hb, H-
2Ab, H-4Aa, H-4Ab, H-4Ba), 3.41 (t, 1 Hb, J 9.1 Hz,
H-3Ab), 3.38ꢁ3.31 (m, 1 Ha, 1 Hb, H-2Aa, H-5Ab),
8
/
/
/
3.14. 1,6-Anhydro-2-azido-3-O-benzyl-2-deoxy-4-O-
trifluoromethanesulfonyl-b-D-galactopyranoside (17)
/
/
A solution of anhyd pyridine (1.6 mL) in freshly distilled
CH2Cl2 (5 mL) was added dropwise at ꢀ15 8C to a
3.25 (br s, 1 Hb, H-2Bb), 3.18 (br s, 1 Ha, H-2Ba), 2.02
(s, 3 Ha, CH3COa), 1.97 (s, 3 Hb, CH3COb). HRMS
/
solution of triflic anhydride (1.55 mL, 9.41 mmol) in
freshly distilled CH2Cl2 (10 mL). This mixture was
added to a solution of 1,6-anhydro 16 (1.7 g, 6.14 mmol)
Calcd for C35H38N6O9 [Mꢂ
/
Na]ꢂ: 709.2598. Found:
709.2599.
in CH2Cl2 (10 mL) kept at ꢀ
/
15 8C. After being stirred
3.12. 1,6-Anhydro-2-azido-3-O-benzyl-2-deoxy-4-O-
trifluoromethanesulfonyl-b- -glucopyranoside (15)
for 1 h at ꢀ15 8C and warmed to 20 8C, the mixture was
diluted with CH2Cl2 (100 mL) and washed successively
with 5% HCl, satd aq NaHCO3 and water. The aqueous
/
D
A solution of anhyd pyridine (3 mL) in freshly distilled
CH2Cl2 (10 mL), cooled at ꢀ15 8C, was added dropwise
to a solution of triflic anhydride (2.3 mL, 13.9 mmol) in
CH2Cl2 (15 mL) cooled at ꢀ15 8C. This mixture was
added to a solution of 1,6-anhydro 7 (2.56 g, 9.24 mmol)
layers were re-extracted with CH2Cl2 (2ꢃ
the combined organic layers were dried and concen-
trated. Chromatography (98:2 CHCl3ꢁEtOAc) of the
residue gave the triflate 17 (2.35 g, 94%) as a glass; [a]D22
328 (c 1, CHCl3); 1H NMR (CDCl3): d 7.45ꢁ
7.30 (m,
/
50 mL), and
/
/
/
ꢂ
/
/

L.L. Morais et al. / Carbohydrate Research 338 (2003) 1369ꢁ
/1379
1377
5 H, aromatics), 5.48 (br s, 1 H, H-1), 5.09 (t, 1 H, J 4.4
Hz, H-4), 4.71 (d, 1 H, J 11.8 Hz, CHPh), 4.65ꢁ4.60 (m,
2 H, H-5, CHPh), 4.58 (d, 1 H, J6,6? 7.9 Hz, H-6), 4.00
CH3CO). Anal. Calcd for C20H25NO9S: C, 52.74; H,
5.53; N, 3.08. Found: C, 52.39; H, 5.46; N, 3.17.
/
(m, 1 H, H-3), 3.79 (dd, 1 H, J5,6? 5 Hz, H-6?), 3.66 (br s,
3.17. 4-S-(3,4,6-Tri-O-acetyl-2-benzyloxycarbonyl-
amino-2-deoxy-b-D-glucopyranosyl)-1,6-anhydro-2-
azido-3-O-benzyl-2-deoxy-4-thio-b-D-glucopyranoside
(22)
1 H, H-2). HRMS Calcd for C14H14F3N3O6S [Mꢂ
/
Na]ꢂ: 432.0453. Found: 432.0448.
3.15. 2-S-(3,4,6-Tri-O-acetyl-2-benzyloxycarbonyl-
amino-2-deoxy-b-
hydrochloride (20)
D
-glucopyranosyl)-2-pseudothiourea
NaH (55% in oil, 459 mg, 10.5 mmol) was added to a
solution of thiol 21 (4.6 g, 10.1 mmol) DMF (90 mL)
stirred at 0 8C. The mixture was stirred for 10 min at
0 8C, 10 min at 20 8C and was, in turn, added to the
triflate 17 (3.45 g, 8.42 mmol). The reaction mixture was
stirred for 1 h at 20 8C, and the reaction was quenched
by addition of HOAc (8 mL), followed by stirring for a
further 30 min at rt. The solvent was removed in vacuo,
and the residue was purified by chromatography on
A mixture of the known carbamate13 (10.7 g, 34.15
mmol) 18 and acetyl chloride (40 mL) was stirred at
20 8C for 20 h. The mixture was diluted with CH2Cl2
(150 mL) and washed successively with a cooled satd aq
solution of NaHCO3 and brine. The aqueous layers were
re-extracted with CH2Cl2 (4ꢃ50 mL), and the com-
/
bined organic layers were dried and concentrated to give
the known chloride 19.14 The syrup (12.8 g, 27.9 mmol)
was dissolved in anhydrous acetone (130 mL), and
thiourea was added (4 g, 52.5 mmol). The mixture was
refluxed for 7 h, cooled to 20 8C, and the pseu-
dothiourea 20 was filtered off as a white solid and
silica gel (7:1 to 1:1 tolueneꢁ
thiodisaccharide 22 (5.32 g, 88%); [a]D22
CHCl3); 1H NMR (CDCl3): d 7.40ꢁ
7.29 (m, 10 H,
aromatics), 5.44 (s, 1 H, H-1B), 5.27 (t, 1 H, J 9.7 Hz,
H-3A), 5.13 (d, 1 H, J 12.2 Hz, CHPh), 5.18ꢁ4.96 (m, 3
H, CHPh, NHA, H-4A), 4.89 (d, 1 H, J1,2 11.1 Hz, H-
1A), 4.74ꢁ4.58 (m, 3 H, CH2Ph, H-5B), 4.22 (d, 1 H,
/
EtOAc) to furnish the
ꢀ
/
138 (c 1,
/
/
washed with acetone (8.5 g, 47%); [a]D22
ꢀ
/
58 (c 1,
/
MeOH); 1H NMR (MeOD): d 7.38ꢁ
/
7.28 (m, 5 H,
J6,6? 7.3 Hz, H-6B), 4.18 (dd, 1 H, J6,6? 12.3 Hz, J5,6? 4.5
Hz, H-6?A), 4.11 (dd, 1 H, J5,6 2.1 Hz, H-6A), 3.84 (s, 1
aromatics), 5.56 (d, 1 H, J1,2 10.7 Hz, H-1), 5.31 (t, 1 H,
J2,3ꢂ3,4 19.1 Hz, H-3), 5.16 (d, 1 H, J 12.4 Hz, CHPh),
H, H-3B), 3.76 (dd, 1 H, J5,6? 5.5 Hz, H-6?B), 3.74ꢁ
(m, 2 H, H-2A, H-5A), 3.52 (s, 1 H, H-2B), 3.19 (s, 1 H,
H-4B), 2.01, 2.02 and 1.95 (3 s, 9 H, 3ꢃ CH3CO). Anal.
/3.60
5.13ꢁ5.01 (m, 2H, CHPh, H-4), 4.29 (dd, 1 H, J6,6? 12.4
/
Hz, J5,6? 4.9 Hz, H-6?), 4.21 (dd, 1H, J5,6 2.2 Hz, H-6),
4.08 (m, 1H, H-5), 3.88 (dd, 1H, J1,2ꢂ2,3 20.2 Hz, H-2),
2.08 (s, 3H, CH3CO), 2.02 (s, 3H, CH3CO) and 1.90 (s,
3H, CH3CO). Anal. Calcd for C21H28ClN3O9S: C,
47.24; H, 5.29; N, 7.87. Found: C, 46.80; H, 5.36; N,
7.74.
/
Calcd for C33H38N4O12S: C, 55.46; H, 5.36; N, 7.84.
Found: C, 55.70; H, 5.34; N, 7.45.
3.18. 1,6-Di-O-acetyl-4-S-(3,4,6-tri-O-acetyl-2-benzyl-
oxycarbonylamino-2-deoxy-b-D-glucopyranosyl)-2-
azido-3-O-benzyl-2-deoxy-4-thio-a,b-D-glucopyranose
(23)
3.16. 3,4,6-Tri-O-acetyl-2-benzyloxycarbonylamino-2-
deoxy-1-thio-b-D-glucopyranose (21)
The thiodisaccharide 22 (5.31 g, 0.074 mmol) was
dissolved in Ac2OꢁTFA (9:1, 80 mL), and the solution
was stirred for 4 h at rt. Solvents were evaporated under
reduced pressure, and residual traces of acid were
eliminated by repeated evaporation with toluene. Chro-
Sodium sulfite (3.98 g, 31.6 mmol) was added to a
solution of the pseudothiourea 20 (8.25 g, 15.8 mmol) in
a mixture of acetone and water (35 mL/210 mL). The
mixture was stirred at 20 8C for 22 h. The pH was
adjusted to 5 by adding 5% HCl, and the solution was
/
matography (9:1, 8:1, 7:1, 6:1 then 5:1 tolueneꢁacetone)
/
extracted with CH2Cl2 (3ꢃ
/
100 mL). The combined
organic layers were washed with brine (100 mL) and
of the dry residue gave compound 23 (5.84 g, 96%) as an
1
anomeric mixture; H NMR in CDCl3 showed a ratio
water (100 mL). The aqueous layers were re-extracted
a:b of 75:25; 1H NMR (CDCl3): d 7.45ꢁ
7.20 (m, 10 Ha,
/
with CH2Cl2 (2ꢃ/100 mL) and the organic layers were
10 Hb, aromatics), 6.27 (d, 1 Ha, J1,2 3.2 Hz, H-1Ba),
5.45 (d, 1 Hb, J1,2 7.3 Hz, H-1Bb), 5.33 (m, 1 Ha, 1 Hb,
combined, dried and concentrated. The crude product
was recrystallized from EtOH to afford the pure thiol 21
H-3Aa, H-3Ab), 5.02ꢁ
/
4.84 (m, 6 Ha, 6 Hb, 2ꢃ
/
(5.67 g, 81%) as a white powder: mp 128 8C; [a]D22
0.99, CHCl3); H NMR (CDCl3): d 7.53 (d, 1 H, JNH,2
ꢂ
/
78 (c
CH2Pha, 2ꢃ CH2Phb, H-4Aa, H-4Ab, H-1Aa, H-
/
1
1Ab), 4.47 (dd, 1 Ha, 1 Hb, J6,6? 12.4 Hz, J5,6? 4.2 Hz, H-
6?Ba, H-6?Bb), 4.38 (d, 1 Ha, 1 Hb, H-6Aa, H-6Ab),
4.15 (dd, 1 Ha, 1 Hb, J6,6? 12.3 Hz, J5,6? 4.6 Hz, H-6?Aa,
H-6?Ab), 4.01 (m, 2 Ha, 1 Hb, H-6Aa, H-6Ab, H-5Ba),
9.7 Hz, NH), 7.40ꢁ
/
7.27 (m, 5 H, aromatics), 5.11ꢁ4.98
/
(m, 3 H, CH2Ph, H-4), 4.85 (t, 1 H, J 9.6 Hz, H-3), 4.75
(d, 1 H, J1,2 10.1 Hz, H-1), 4.14 (dd, 1 H, J6,6? 12.2 Hz,
J5,6? 4.8 Hz, H-6?), 3.99 (m, 1 H, H-6), 3.81 (m, 1 H, H-
3.80ꢁ
/
3.72 (m, 1 Ha, 1 Hb, H-3Ba, H-5Bb), 3.65ꢁ
/
3.55
5), 3.54 (ddd, 1 H, H-2), 2.01, 1.95 and 1.84 (3 s, 3ꢃ
/
(m, 3 Ha, 3 Hb, H-2Ba, H-2Bb, H-2Aa, H-2Ab, H-5Aa,

1378
L.L. Morais et al. / Carbohydrate Research 338 (2003) 1369ꢁ1379
/
H-5Ab), 3.40 (m, 1 Hb, H-3Bb), 2.99 (t, 1 Ha, J3,4ꢂ4,5
20.8 Hz, H-4Ba), 2.96 (m, 1 Hb, H-4Bb), 2.19, 2.07,
described above for the preparation of imidate 11.
Chromatography on a column of alumina (2:1, 1:1, 1:2
2.03, 2.01 and 1.91 (5 s, 15 H, 5ꢃ
Calcd for C37H44N4O15S [Mꢂ
Na]ꢂ: 839.2422. Found:
839.2424.
/
CH3CO). HRMS
and 1:3 cyclohexaneꢁEtOAc) gave the imidate 25 (3.91
/
1
g, 82%) as a glass; H NMR in CDCl3 showed a ratio
/
a:b of 80:20; 1H NMR (CDCl3): d 8.76 (s, 1 Ha,
NHBa), 8.73 (s, 1 Hb, NHBb), 7.48ꢁ7.26 (m, 10 Ha, 10
/
Hb, aromatics), 6.47 (d, 1 Ha, J1,2 3.3 Hz, H-1Ba), 5.61
(d, 1 Hb, J1,2 8.6 Hz, H-1Bb), 5.33 (m, 1 Ha, 1 Hb, H-
3.19. 6-O-Acetyl-4-S-(3,4,6-tri-O-acetyl-2-benzyloxy-
carbonylamino-2-deoxy-b- -glucopyranosyl)-2-
azido-3-O-benzyl-2-deoxy-4-thio-a,b-D-glucopyranose
D
3Aa, H-3Ab), 5.08ꢁ
2ꢃ CH2Phb, H-1Aa, H-1Ab, NHAa, NHAb, H-4Aa,
H-4Ab), 4.54ꢁ4.43 (m, 2 Ha, 2 Hb, H-6Ba, H-6Bb, H-
6?Ba, H-6?Bb), 4.22ꢁ4.07 (m, 2 Ha, 2 Hb, H-5Ba, H-
/
4.08 (m, 7 Ha, 7Hb, 2ꢃ CH2Pha,
/
/
(24)
/
/
Hydrazine acetate (920 mg, 9.99 mmol) was added to a
solution of the diacetate 23 (5.84 g, 7.15 mmol) in DMF
(70 mL). The reaction mixture was stirred for 5 h at rt,
the solvent was evaporated under reduced pressure and
residual traces of DMF were eliminated by repeated
evaporation with toluene. The residue was diluted with
EtOAc (150 mL), and the solution was washed succes-
5Bb, H-6?Aa, H-6?Ab), 4.01 (dd, 1 Ha, J5,6 2.1 Hz, J6,6?
12.3 Hz, H-6Aa), 3.86 (t, 1 Ha, 1 Hb, J2,3ꢂ3,4 19.6 Hz,
H-3Ba, H-3Bb), 3.77ꢁ
2Bb), 3.66ꢁ3.52 (m, 2 Ha, 2 Hb, H-2Aa, H-2Ab, H-
5Aa, H-5Ab), 3.07 (t, 1 Ha, J 10.7 Hz, H-4Ba), 3.00 (t, 1
Hb, J 10.7 Hz, H-4Bb), 2.12ꢁ1.99 (m, 9 Ha, 9 Hb, 3ꢃ
CH3COa, 3ꢃ CH3COb), 1.94ꢁ1.89 (m, 3 Ha, 3 Hb,
CH3COa, CH3COb).
/
3.70 (m, 1 Ha, 1 Hb, H-2Ba, H-
/
/
/
/
/
sively with brine (2ꢃ
/
100 mL) and water (2ꢃ100 mL).
/
The washings were re-extracted with EtOAc (100 mL),
and the combined organic extracts were dried and
concentrated. Chromatography of the residue (3:1, 2:1,
3.21. 4-O-[6-O-Acetyl-4-S-(3,4,6-tri-O-acetyl-2-benzyl-
oxycarbonylamino-2-deoxy-b- -glucopyranosyl)-2-
azido-3-O-benzyl-2-deoxy-4-thio-b- -glucopyranosyl]-
1,6-anhydro-2-azido-3-O-benzyl-2-deoxy-b- -glucopy-
ranoside (26b) and 4-O-[6-O-acetyl-4-S-(3,4,6-tri-O-
acetyl-2-benzyloxycarbonylamino-2-deoxy-b- -gluco-
pyranosyl)-2-azido-3-O-benzyl-2-deoxy-4-thio-a-
glucopyranosyl]-1,6-anhydro-2-azido-3-O-benzyl-2-
deoxy-b- -glucopyranoside (26a)
D
1:1 tolueneꢁEtOAc) gave the anomeric mixture of
/
D
1
hemiacetal 24 (4.5 g, 81%); H NMR in CDCl3 showed
D
a ratio a:b of 6:4; 1H NMR (CDCl3): d 7.43 (m, 2 Ha, 2
Hb, aromatics), 7.35ꢁ
7.24 (m, 2 Ha, 2 Hb, aromatics), 5.37 (br s, 1 Ha, H-
1Ba) 5.32ꢁ5.25 (m, 1 Ha, 1 Hb, H-3Aa, H-3Ab), 5.08ꢁ
4.83 (m, 7 Ha, 7 Hb, 2ꢃ CH2Pha, 2ꢃ CH2Phb, H-
1Aa, H-1Ab, H-4Aa, H-4Ab, NHa, NHb), 4.60 (m, 2
Hb, H-1Bb, H-6Bb), 4.53ꢁ4.40 (m, 2 Ha, H-6Ba, H-
/
7.28 (m, 6 Ha, 6 Hb, aromatics),
D
D-
/
/
/
/
D
/
A suspension of the alcohol 7 (1.50 g, 5.41 mmol) and
imidate 25 (2.48 g, 2.70 mmol) in dry CH2Cl2 (100 mL)
˚
containing 3 A activated molecular sieves (800 mg) was
stirred under Ar at rt for 1 h. The reaction mixture was
6?Ba), 4.32 (dd, 1 Hb, J6,6? 11.8 Hz, J5,6? 5.4 Hz, H-6?Bb),
4.27 (ddd, 1 Ha, J4,5 11.2 Hz, J5,6? 4.1 Hz, J5,6 3.1 Hz, H-
5Ba), 4.18ꢁ
6?Aa, H-6?Ab), 3.90 (t, 1 Ha, J2,3ꢂ3,4 19.8 Hz, H-3Ba),
3.70ꢁ3.58 (m, 2 Ha, 3 Hb, H-5Bb, H-2Aa, H-2Ab, H-
/
4.03 (m, 2 Ha, 2 Hb, H-6Aa, H-6Ab, H-
cooled to ꢀ
was added. The reaction mixture was allowed to warm
up to ꢀ20 8C over 1 h and was subsequently stirred for
2.5 h at ꢀ20 8C. Et3N (100mL) was added, and the
/
78 8C, and BF3×Et2O (68 mL, 0.540 mmol)
/
/
5Aa, H-5Ab), 3.49 (dd, 1 Ha, J1,2 3.2 Hz, J2,3 9.6 Hz, H-
2Ba), 3.41 (dd, 1 Hb, J1,2 8 Hz, J2,3 9.3 Hz, H-2Bb), 3.31
(dd, 1 Hb, J3,4 10,5 Hz, H-3Bb), 2.95 (t, 1 Ha, J4,5 10,5
/
/
molecular sieves were decanted and washed with
CH2Cl2. The supernatant and washings were combined,
diluted with CH2Cl2 (75 mL) and washed with water
Hz, H-4Ba), 2.90 (t, 1 Hb, J 10,5 Hz, H-4Bb), 2.09ꢁ
/2.08
(2 s, 3 Ha, 3 Hb, CH3COa, CH3COb), 2.06 (s, 3 Ha, 3
Hb, CH3COa, CH3COb), 2.01 (s, 3 Ha, 3 Hb, CH3COa,
CH3COb), 1.91 (s, 3 Ha, 3 Hb, CH3COa, CH3COb).
(2ꢃ
CH2Cl2 (2ꢃ
were dried and concentrated. Chromatography (5:1, 4:1,
3:1 and 2:1, cyclohexaneꢁAcOEt) of the residue gave the
/100 mL). The washings were re-extracted with
/75 mL), and the combined organic layers
HRMS Calcd for C35H42N4O14S [Mꢂ
/
Na]ꢂ: 797.2316.
Found: 797.2312.
/
trisaccharide 26 (1.59 g, 57%) as an anomeric mixture.
3.20. 6-O-Acetyl-4-S-(3,4,6-tri-O-acetyl-2-benzyloxy-
carbonylamino-2-deoxy-b- -glucopyranosyl)-2-
azido-3-O-benzyl-2-deoxy-4-thio-a-D-glucopyranosyl
The anomers were separated by HPLC (Waters Pre-
pNova Pack† silica 125 A, 40ꢃ
100 mm, sample
˚
concentration 40 mg/mL, volume injected 8 mL, flow
D
/
trichloroacetimidate (25)
rate: 15 mL/min of 65:35 hexaneꢁEtOAc) to give 26a
/
(276 mg) and 26b (1.30 g).
Reaction of hemiacetal 24 (4 g, 5.16 mmol) with
trichloroacetonitrile (10.3 mL, 103 mmol) and DBU
(200 mL, 1.34 mmol), as well as work-up of the reaction,
were carried out using the same conditions than those
3.21.1. Analytical data for 26b.
1H NMR (CDCl3): d 7.48ꢁ
5.52 (s, 1 H, H-1C), 5.32 (m, 1 H, H-3A), 5.06ꢁ4.82 (m,
/
[a]2D3
7.24 (m, 15 H, aromatics),
ꢀ128 (c 1, CHCl3);
/
/
/

L.L. Morais et al. / Carbohydrate Research 338 (2003) 1369ꢁ
/1379
1379
6 H, 2ꢃ
Hz, NHA), 4.75ꢁ
4.41 (d, 1 H, J1,2 8 Hz, H-1B), 4.27 (dd, 1 H, J5,6? 5 Hz,
J6,6? 12 Hz, H-6?B), 4.20ꢁ4.12 (m, 2 H, H-6C, H-6?A),
4.07 (d, J6,6? 12 Hz, H-6A), 3.96 (s, 1 H, H-4C), 3.81 (t, 1
H, J 6.7 Hz, H-6?C), 3.76 (s, 1 H, H-3C), 3.63 (m, 1 H,
/
CH2Ph, H-1A, H-4A), 4.77 (d, 1 H, JNH,2
8
funded by CFI, OIT and NSERC (Canada). The
/
4.59 (m, 4 H, CH2Ph, H-5C, H-6B),
authors are grateful for a grant from the France-Canada
Research Foundation to support a collaborative ex-
change between the French and Canadian groups. The
authors thank Dr P. Westerduin (ORGANON Labora-
tories) for the generous gift of precursor of compound 7.
/
H-5A), 3.57 (t, 1 H, J 8.7 Hz, H-2B), 3.54ꢁ
H-2A, H-5B), 3.27ꢁ3.20 (m, 2 H, H-2C, H-3B), 2.90 (t,
1 H, J 10.9 Hz, H-4B), 2.04, 2.02, 2.01 and 1.91 (4 s, 12
H, 4ꢃ
CH3CO). 13C NMR (100 MHz, CDCl3): d
170.44, 170.39, 170.23, 169.40 (4ꢃ COCH3,
/
3.41 (m, 2 H,
/
/
References
/
NCOCH2Ph), 137.61 (Cipso aromatic), 101.68 (C-1B),
100.68 (C-1C), 82.23 (C-1A), 79.37 (C-3B), 77.22 (C-3C,
1. Auzanneau, F.-I.; Mialon, M.; Prome´, D.; Prome´, J.-C.;
Gelas, J. J. Org. Chem. 1998, 63, 6460ꢁ
2. Van Rhin, P.; Venderleyden, J. Microbiol. Rev. 1995, 59,
124ꢁ142.
/6465.
C-4C), 75.84 (C-5A), 75.11 (2ꢃ CH2Ph), 74.71 (C-5B),
/
74.53 (C-5C), 72.51 (CH2Ph, C-3A), 68.48 (C-4A), 67.00
(C-2B), 65.00 (C-6C), 64.12 (C-6B), 62.12 (C-6A), 59.23
(C-2C), 55.99 (C-2A), 45.76 (C-4B). Anal. Calcd for
C48H55N7O17S: C, 55.75; H, 5.36; N, 9.48. Found: C,
55.93; H, 5.41; N, 9.19.
/
3. Truchet, G.; Roche, P.; Lerouge, P.; Vasse, J.; Camut, S.;
de Billy, F.; Prome´, J.-C.; De´narie´, J. Nature 1991, 351,
670ꢁ
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673.
4. Spaink, H. P. Annu. Rev. Microbiol. 2000, 54, 257ꢁ
/288.
5. Schultze, M.; Quiclet-Sire, B.; Kondorosi, E.; Virelizier,
H.; Glushka, J. N.; Endre, G.; Gero, S. D.; Kondorosi, A.
3.21.2. Analytical data for 26a.
1H NMR (CDCl3): d 7.42ꢁ
7.25 (m, 15 H, aromatics),
5.56 (s, 1 H, H-1C), 5.20 (m, 1 H, H-3A), 5.07 (t, 1 H, J
9.6 Hz, H-4A), 5.02ꢁ4.92 (m, 3 H, 2ꢃ CHPh, H-1A),
4.90 (d, 1 H, J1,2 3.4 Hz, H-1B), 4.85ꢁ4.74 (m, 3 H,
/
[a]2D3
ꢂ148 (c 1, CHCl3);
/
Proc. Natl. Acad. Sci. USA 1992, 89, 192ꢁ196.
/
/
6. Defaye, J.; Gelas, J. in: Atta-ur-Rahman (Ed.), Studies in
Natural Products Chemistry, vol. 8, Elsevier Science
/
/
Publishers: Amsterdam. 1991; pp. 315ꢁ357.
/
/
7. Auzanneau, F.-I.; Bennis, K.; Fanton, E.; Prome´, D.;
Defaye, J.; Gelas, J. J. Chem. Soc., Perkin Trans. 1 1998,
CHPh, H-5C, NHA), 4.72 (d, 1 H, J 11.9 Hz, CHPh),
4.63 (m, 2 H, H-6?B, CHPh), 4.57 (d, 1 H, J 10.4 Hz,
3629ꢁ
8. Tailler, D.; Jacquinet, J.-C.; Beau, J.-M. J. Chem. Soc.,
Chem. Commun. 1994, 1827ꢁ1828.
9. Schmidt, R. R.; Kinzy, W. Adv. Carbohydr. Chem.
Biochem. 1994, 50, 21ꢁ123.
10. Tailler, D.; Jacquinet, J.-C.; Noirot, A.-M.; Beau, J.-M. J.
Chem. Soc., Perkin Trans. 1 1992, 3163ꢁ3164.
/
3635.
CHPh), 4.43ꢁ
2 H, H-6A, H-6?C), 4.11 (m, 1 H, H-6C), 4.01 (t, 1 H, J
10 Hz, H-3B), 3.87 (s, 1 H, H-4C), 3.83ꢁ3.64 (m, 3 H,
/
4.33 (m, 2 H, H-5B, H-6B), 4.22ꢁ
/
4.14 (m,
/
/
/
H-5A, H-2A, H-6?A), 3.53 (s, 1 H, H-3C), 3. 31 (dd, 1 H,
J1,2 3.2 Hz, J2,3 9.7 Hz, H-2B), 3.14 (s, 1 H, H-2C), 2.88
(t, 1 H, J 10.9 Hz, H-4B), 2.06, 2.04, 2.02 and 1.87 (4 s,
/
11. Zuurmond, H. M.; van der Klein, P. A. M.; de Wildt, J.;
van der Marel, G. A.; van Boom, J. H. J. Carbohydr.
12 H, 4ꢃ
170.65, 170.42, 169.39 (4ꢃ
/
CH3CO). 13C NMR (100 MHz, CDCl3): d
COCH3, NCOCH2Ph),
/
Chem. 1994, 13, 323ꢁ
12. Wang, L.-X.; Lee, Y. C. J. Chem. Soc., Perkin Trans. 1
1996, 581ꢁ591.
13. Onodera, K.; Komano, T. J. Org. Chem. 1961, 26, 3932ꢁ
/
339.
137.50, 136.80, 135.96 (Cipso aromatic), 101.04 (C-
1B), 100.75 (C-1C), 81.92 (C-1A), 78.69 (C-3C), 77.45
(C-4C), 75.92 (C-3B), 75.63 (CH2Ph), 74.86 (C-5A, C-
5C) 73.19 (C-3A), 72.93 (CH2Ph), 70.30 (C-5B), 68.18
(C-4A), 67.00 (CH2Ph), 64.82 (C-2B), 64.73 (C-6A),
63.89 (C-6B), 61.84 (C-6C), 58.37 (C-2C), 55.43 (C-2A),
47.26 (C-4B). Anal. Calcd for C48H55N7O17S: C, 55.75;
H, 5.36; N, 9.48. Found: C, 55.86; H, 5.56; N, 9.18.
/
/
3933.
14. Stevens, C. L.; Nagarajan, K. J. Med. Pharm. Chem. 1962,
5, 1124ꢁ
15. Horton, D.; Wolfrom, M. L. J. Org. Chem. 1962, 27,
1794ꢁ1800.
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92, 1167ꢁ1195.
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2000, 2, 3841ꢁ3843.
/
1148.
/
/
Acknowledgements
/
L. Loureiro-Morais is supported by a grant from the
French ministry in charge of higher education (France).
The authors are very thankful to E. Fanton for her
technical assistance. The HPLCs used in this work were
/
19. Perrin, D. D.; Armarego, W. L. F. Purification of
Laboratory Chemicals; 3rd ed.; Pergamon Press: Oxford,
1988.