Synthesis and NMR analysis of 13C-labeled oligosaccharides corresponding to the major glycolipid from Mycobacterium leprae

Article abstract of DOI:10.1016/S0008-6215(97)10101-X

An improved synthesis of propyl 4-O-(3,6-di-O-methyl-β-D- glucopyranosyl)-2,3-di-O-methyl-α-L-rhamnopyranoside, a disaccharide corresponding to the phenolic glycolipid of Mycobacterium leprae using a trichloroacetimidate as a glycosyl donor is described. The synthetic strategy is also applied to the preparation of three corresponding disaccharide analogues containing ¹³C-labeled methyl groups. The preparation of the trisaccharide, propyl 2-O-[4-O-(3,6-di-O-methyl-β-D-glucopyranosyl)-2,3-di- O-methyl-α-L-rhamnopyranosyl]-3-O-methyl-α-L-rhamnopyranoside is also reported. The di- and tri-saccharides were characterized by ¹H and ¹³C NMR spectroscopy.

Full text of DOI:10.1016/S0008-6215(97)10101-X

Carbohydrate Research 306 (1998) 493±503
13
Synthesis and NMR analysis of C-labeled
oligosaccharides corresponding to the major
glycolipid from Mycobacterium leprae
Ximao Wua, Jose-R. Marino-Albernasa, France-Isabelle Auzanneaua,
Vicente Verez-Bencomob, B. Mario Pintoa*
aDepartment of Chemistry, Simon Fraser University, Burnaby, B.C., Canada, V5A 1S6
b
Â
Laboratory for Carbohydrate Chemistry, Facultad de Quõmica, Universidad de la Habana and Centro
Nacional de Biopreparados, Ciudad Habana, Cuba
Received 4 September 1997; accepted in revised form 10 November 1997
Abstract
An improved synthesis of propyl 4-O-(3,6-di-O-methyl-ꢀ-d-glucopyranosyl)-2,3-di-O-methyl-ꢁ-
l-rhamnopyranoside, a disaccharide corresponding to the phenolic glycolipid of Mycobacterium
leprae using a trichloroacetimidate as a glycosyl donor is described. The synthetic strategy is also
applied to the preparation of three corresponding disaccharide analogues containing 13C-labeled
methyl groups. The preparation of the trisaccharide, propyl 2-O-[4-O-(3,6-di-O-methyl-ꢀ-d-glu-
copyranosyl)-2,3-di-O-methyl-ꢁ-l-rhamnopyranosyl]-3-O-methyl-ꢁ-l-rhamnopyranoside is also
reported. The di- and tri-saccharides were characterized by 1H and 13C NMR spectroscopy.
# 1998 Elsevier Science Ltd. All rights reserved
Keywords: Mycobacterium leprae; Synthesis; Oligosaccharide haptens; 13C-labeled
1. Introduction
Mycobacterium leprae produces a unique phe-
nolic glycolipid [1,2]:
Antibodies against oligosaccharides of this glycoli-
pid have been detected in the sera of leprosy
patients [2±5], suggesting that the oligosaccharides
might be of value as diagnostic reagents or as
components of vaccines. Synthetic [6±18] and con-
formational [18] studies of the di- and tri-sacchar-
ides have been reported, and immunochemical
studies [7,8] have shown that the disaccharide 1
* Corresponding author.
0008-6215/98/$19.00 # 1998 Elsevier Science Ltd. All rights reserved
PII S0008-6215(97)10101-X

494
X. Wu et al./Carbohydrate Research 306 (1998) 493±503
bound to antibodies and was also e€ective in the
serodiagnosis of leprosy. The design of superior
immunodiagnostic reagents requires a detailed
understanding of the interaction between hapten
and antibody. The use of 13C-labeled compounds
should thus prove useful [19±25].
We report herein the improved synthesis and
NMR characterization of propyl 4-O-(3,6-di-O-
methyl-ꢀ-d-glucopyranosyl)-2,3-di-O-methyl-ꢁ-l-
rhamnopyranoside and three corresponding 13C-
labeled disaccharide analogues. These compounds
will serve as initial substrates with which to test the
NMR methods of analysis. The preparation
and NMR of the trisaccharide hapten, propyl 2-O-
[4-O-(3,6-di-O-methyl-ꢀ-d-glucopyranosyl)-2,3-di-O-
methyl-ꢁ-l-rhamnopyranosyl]-3-O-methyl-ꢁ-l-
rhamnopyranoside, is also reported.
the spectrum of 10. The labeled compound 13 was
similarly obtained by monomethylation of 10 with
13C-labeled methyl iodide. Compound 13 (54%)
was, in turn, methylated at O-2 with unlabeled
methyl iodide to give the dimethyl ether 14 quan-
titatively. The compound was labeled at O-3 (not )-
2) because of its proximity to the glucosyl unit at
O-4 in the disaccharide, with the expectation that
this would facilitate analysis of conformations about
the glycosidic linkage. Hydrogenolysis of the ben-
zyl ether in compounds 11 and 14 led, as expected,
to reduction of the allyl group to a propyl group,
and gave the glycosyl acceptors 15 and 16, respec-
tively. Substitution at O-3 by a 13C-labeled methyl
group and at O-2 by an unlabeled methyl group in
compound 16 was con®rmed by an inverse 13C±1H
correlation NMR experiment, optimized for long-
range correlations. The spectrum showed an
intense cross peak between the 13C-labeled methyl
2. Results and discussion
signal (56.9 ppm) and the H-3 signal (3.43 ppm),
corresponding to J13
3
3, and a less intense
cross peak between the unlabeled methyl signal
(58.9 ppm) and the H-2 signal, corresponding to
CH3;H
The unlabeled glycosyl donor 8 was prepared
from the known diacetate 3 [6,15]. The corre-
sponding labeled derivative 9 was synthesized from
the benzoxymethylether 1 [26]. Methylation of 1
with an excess of methyl-13C iodide gave the dime-
3JCH ;H 2. An additional crosspeak was observed
3
between the 13C labeled methyl signal and the H-4
signal (3.54 ppm), corresponding to 4J13
.
4
CH3;H
1
thyl ether 2 in 93% yield. The H NMR spectrum
of 2 showed two methyl signals which appeared as
The allyl glycoside 11 was also treated with palla-
dium (II) chloride [31] and the resulting hemiacetal
17 was hydrogenolyzed to give the diol 18. Acet-
ylation of 18 gave the diacetate 19 which was used
as a glycosyl donor in the synthesis of the tri-
saccharide 30 (see below).
doublets (1J13 ˆ 141 and 142 Hz), and signals
C;H
corresponding to H-3, H-6 and H-60 showed addi-
tional coupling (4.5, 2.5, and 4 Hz, respectively) to
the labelled 13CH3. Hydrolysis of compound 2 gave
the triol 4 that was, in turn, acetylated to yield the
triacetate 5. Treatment of 3 and 5 with hydrazine
acetate [27] gave the corresponding hemiacetals 6
and 7, which were converted to the trichloro-
acetimidates 8 and 9, respectively, by reaction with
trichloroacetonitrile and K2CO3 [28].
The preparation of disaccharides 24±27 and tri-
saccharide 32 was accomplished using allyl 4-O-
benzyl-ꢁ-l-rhamnopyranoside 10 [29] as a common
precursor. Methylation of the diol 10 with methyl
iodide in DMF containing sodium hydride gave
the dimethylated compound 11 quantitatively.
Regioselective monomethylation of the equatorial
hydroxyl group of the diol 10 with methyl iodide
was achieved via the corresponding stannylene
acetal [30] and gave the methyl ether 12 (71%). The
regioselectivity of the methylation reaction was
con®rmed by the down®eld shift of C-3 (71.5
to 80.0 ppm) in the 13C NMR spectrum; the shift of
C-2 (67.3 ppm) was similar to that (67.9 ppm) in

X. Wu et al./Carbohydrate Research 306 (1998) 493±503
495
Fig. 1. Partial (a) 1H and (b) 13C NMR spectra of the 13C-
labeled disaccharide 27.
Glycosylation reactions with the trichloro-
acetimidate derivatives 8 and 9 were performed
under catalysis with triethylsilyl tri¯ate (TESOTf).
Hence, glycosylation of 15 and 16 with the tri-
chloroacetimidate 8 gave disaccharides 20 (99%)
and 21 (93%), respectively. Similarly, glycosylation
of 15 and 16 with the labeled trichloroacetimidate
3. Experimental
General methods.ÐMelting points (mps) were
measured on a Fisher±Johns melting point appa-
ratus and are uncorrected. Optical rotations were
measured on a Rudolph Research Autopol II
automatic polarimeter. 1H NMR (400.13 MHz),
13C NMR (100.6 MHz) spectra were recorded on a
Bruker AMX-400 NMR in CDCl3 (internal stan-
dard, for 1H: residual CHCl3 ꢂ 7.24; for 13C:
CDCl3 ꢂ 77.0), unless otherwise stated. Chemical
shifts and coupling constants were obtained from a
9
gave disaccharides 22 (71%) and 23
(79%), respectively. Zemplen deacetylation of
disaccharides 20±23 gave the deprotected dis-
accharides 24±27, respectively. The 13C NMR
spectra of these disaccharides indicated that the
3
13
CH3
J
coupling pathways required for fur-
O C H
ther NMR experiments with antibody-hapten
complexes e.g., isotope-®ltered experiments were
clearly present (e.g. Fig. 1).
1
®rst-order analysis of the spectra. H-1H COSY
and inverse 13C-1H correlated spectra were
acquired with data sets of 2K(F2)Â512(F1), the
FIDs were zero-®lled to a 1K(F2)Â1K(F1) data
set, and processed using a sine-squared apodization
function with a shift of 2 in F1 and F2. The spectra
were displayed in the absolute value mode. For the
inverse detection experiments, a 4-pulse sequence
The trisaccharide 30 was synthesized as follows.
The disaccharide 28 was prepared by glycosylation
of the acceptor 12 with the diacetate 19 in the pre-
sence of BF3±Et2O as a catalyst [17]. The con®g-
uration of the glycosidic linkage was con®rmed by
the 1JC
coupling constant of 171 Hz [32].
1
1;H
1
Zemplen deacetylation of disaccharide 28 gave the
glycosyl acceptor 29 which was, in turn, glycosy-
lated with the trichloroacetimidate 8 to give the
trisaccharide 30. Deprotection of the trisaccharide
30 by deacetylation followed by hydrogenolysis
a€orded the trisaccharide 32.
was used for the H{13C}±13C correlation [33]; the
same sequence, incorporating a BIRD pulse in the
1
preparation period, was used for the H±13C cor-
relation [34]. The digital resolution in the inverse
13C±1H spectra was 1 Hz/pt. The inverse 13C±1H
spectra for detecting long-range correlation were

496
X. Wu et al./Carbohydrate Research 306 (1998) 493±503
acquired with data sets of 1K(F2)Â250(F1). The
mixing time was 90 ms and the digital resolution
was 2 Hz/pt. Microanalyses were measured with an
Elemental Analyzer-MDD 1106. The percentage of
carbon was detected as the total number of moles
of labeled and unlabeled CO2 produced by the
molecule. Whereas the molecular weight of a com-
pound is sensitive to the presence of 13C, the weight
of carbon that it contains measured by elemental
analysis is insensitive to the isotopic labeling. This
was taken into account in the calculated analyses
for the labeled compounds in which the molecular
weights were calculated using 13.01 as the atomic
weight of the labeled carbon while 12.01 was used
for the calculation of the total weight of labeled
and unlabeled carbon in the molecule.
Thin-layer chromatography (TLC) was per-
formed on precoated aluminum plates with Kie-
selgel silica gel 60 F254 (E. Merck) and detected
with UV light and/or charred with 5% sulfuric acid
in EtOH solution. All compounds were puri®ed by
¯ash column chromatography with Kieselgel silica
gel 60 (230±400 mesh) according to a published
procedure [35]. Solvents were dried and distilled
according to standard procedures [36]. Reactions
performed under N2 were carried out in deox-
ygenated solvents and transfers under N2 were
e€ected by means of standard Schlenk-tube tech-
niques. Organic solutions were dried over Na2SO4
and concentrated below 40 ꢀC under reduced pres-
sure. Methyl±13C iodide (99%±13C) was purchased
from Sigma Company.
(dd, 1 H, J4,3 3 Hz, J4,5 9.5 Hz, H-4), 4.05 (m, 1 H,
J5,6 2 Hz, J5,6 3 Hz, H-5), 3.78 (dd, 1 H, JH,13C
3
0
3
13
0
4.5 Hz, H-3), 3.76 (dt, 1 H, J6,6 11 Hz, JH,
13
C
2.5 Hz, H-6), 3.60 (dt, 1H, 3JH, C, 4 Hz, H-60), 3.39
(d, 3 H, JH, C 141 Hz, O13CH3), 3.37 (d, 3 H,
1
13
1JH, C 142 Hz, O13CH3), 1.50, 1.32 [2s, 2Â3 H,
13
(CH3)2C]. 13C NMR: ꢂ 138.0, 128.4, 127.8, 127.6
(Ar), 111.8 [(CH3)2C]; 105.1 (C-1), 94.7 (OCH2O),
83.5 (C-3), 81.0 (C-2), 78.7 (C-4), 73.8 (C-5), 73.0
1
(C-6), 69.6 (OCH2Ph), 59.3 (qt, J13
141 Hz,
C,H
3J13
3J13
ꢁ 3 Hz, O13CH3-6), 57.2 (qd, 1J13 142 Hz,
C,H-6
C,H
5 Hz, O13CH3-3), 26.8, 26.4 [2Â(CH3)2C].
C,H-3
Anal. Calcd for C1713C2H28O7: C, 61.59; H, 7.63.
Found: C, 61.84; H, 7.68.
2,4-Di-O-acetyl-3,6-di-O-methyl-a-d-glucopyrano-
syl trichloroacetimidate (8).ÐHydrazine acetate
(250 mg, 2.8 mmol) was added to a solution of 1,2,4-
tri-O-acetyl-3,6-di-O-methyl-ꢁ,ꢀ-d-glucopyranose
[6,15] 3 (0.76 g, 2.2 mmol) in DMF (12 mL) and the
reaction mixture was stirred for 24 h under N2 at
room temperature. The product was extracted with
dichloromethane and washed with water. The
organic phase was dried and concentrated to give
the crude hemiacetal 6 as a syrup (910 mg) that was
dried overnight under high vacuum and dissolved
in anhydrous CH2Cl2 (50 mL). Anhydrous K2CO3
(3.1 g, 23 mmol), and trichloroacetonitrile (3.2 mL,
32 mmol) were added to the mixture that was stir-
red for 48 h at room temperature. Excess K2CO3
was removed by ®ltration through Celite 545 and
the ®ltrate was concentrated. Chromatography
(EtOAc±hexanes, 1:3) of the residue gave the tri-
chloroacetimidate 8 as a colorless syrup (970 mg,
46%); its purity was con®rmed by NMR spectro-
scopy and it was used directly in the glycosylation
5-O-Benzoxymethyl-1,2-O-isopropylidene-3,6-di-
O-13C-methyl-a-d-glucofuranose (2).ÐA solution
of 5-O-benzoxymethyl-1,2-O-isopropylidene-ꢁ-d-
glucofuranose 1 [26] (2.4 g, 6.9 mmol) in DMF
(10 mL) was transferred under N2 to a cooled sus-
pension of NaH (1.4 g, 60% by weight in oil,
34 mmol) in DMF (3 mL). After stirring for 30 min
at 0 ꢀC, methyl±13C iodide (2 g, 14 mmol) was
added dropwise and the reaction was allowed to
proceed for 6 h at room temperature. MeOH
(4 mL) was added to destroy excess NaH, the mix-
ture was poured into ice-water (50 mL), and the
product was extracted with CH2Cl2 (2Â50 mL).
The extracts were washed with water (30 mL),
dried, and concentrated. Chromatography of the
residue (EtOAc±hexanes, 1:3) gave the title com-
1
reactions. H NMR: ꢂ 8.60 (s, C=NH), 6.48 (d, 1
H, J1,2 4 Hz, H-1), 5.08 (dd, 1 H, J4,3+J4,5=20 Hz,
H-4), 4.98 (dd, 1 H, J2,3 10 Hz, H-2), 4.01 (m, 1 H,
H-5), 3.80 (t, 1 H, H-3), 3.46 (dd, 1 H, J6,5 3 Hz,
J6,6 11 Hz, H-6), 3.43 (dd, 1 H, J6 ,5 5 Hz, H-60),
3.46, 3.40 (2 s, 2Â3 H, 2ÂOCH3), 2.11, 2.02 (2 s,
2Â3 H, 2ÂCH3CO). 13C NMR: ꢂ 169.7, 169.3
(2ÂC=O), 160.8 (C=NH), 93.5 (C-1), 91.0 (CCl3),
78.2 (C-3), 71.7 (C-2), 71.6 (C-5), 71.2 (C-6), 69.8
(C-4), 59.9, 59.3 (2ÂOCH3), 20.7, 20.5 (2ÂCH3CO).
2,4-Di-O-acetyl-3,6-di-O-13C-methyl-a-d-gluco-
pyranosyl trichloroacetimidate (9).ÐA solution of
2 (2.3 g, 6.3 mmol) in a mixture of dioxane (13 mL)
and 0.5 N aq HCl (16 mL) was re¯uxed for 1 h.
Toluene was added and the solvents were evapo-
rated. Chromatography (EtOAc±hexanes±MeOH,
4:4:1.5) gave an anomeric mixture of 3,6-di-O-13C-
0
0
1
pound 2 as a syrup (2.4 g, 93%). H NMR: ꢂ 7.36
(m, 5 H, Ar), 5.86 (d, 1 H, J1,2 4 Hz, H-1), 4.88 (dd,
2 H, OCH2O), 4.73 (d, 1 H, J 12 Hz, OCHHPh),
4.61 (d, 1 H, OCHHPh), 4.58 (d, 1 H, H-2), 4.30

X. Wu et al./Carbohydrate Research 306 (1998) 493±503
497
methyl-ꢁ,ꢀ-d-glucopyranose (4) as a white solid
(2.1 g, 100%). H NMR[D2O, internal standard:
2Â30 mL) and the extracts were combined, dried,
1
and concentrated. Chromatography (EtOAc±hex-
anes, 1:3) of the residue gave 11 as a syrup (3.5 g,
sodium
trimethylsilyl-(2,2,3,3-tetradeutero)pro-
67ꢀ (c 1.5, CH2Cl2).
NMR: ꢂ
1H
pionate, ꢂ 0.0]: ꢂ 5.14 (d, J1,2 4 Hz, H-1ꢁ), 4.58 (d,
100%), [ꢁ]22
d
1
13
J1,2 8 Hz, H-1ꢀ), 3.56 (d, JH, C 143 Hz, O13CH3-
7.35 (m, 5 H, Ar), 5.89 (m, 1 H, OCH2CH=CH2),
5.23 (m, 2 H, OCH2CH=CH2), 4.91 (d, 1 H, J
11 Hz, OCHHPh), 4.89 (d, 1 H, J1,2 2 Hz, H-1),
4.60 (d, 1 H, OCHHPh), 4.05 (m, 2 H,
OCH2CH=CH2), 3.68 (m, 1 H, H-5), 3.62±3.60
(m, 2 H, H-2, H-3), 3.51 (s, 6 H, 2ÂOCH3), 3.43 (t,
1 H, J4,3+J4,5=19 Hz, H-4), 1.32 (d, 3 H, H-6).
13C NMR: ꢂ 133.8 (OCH2CH=CH2), 128.3, 127.9,
127.5 (Ar), 117.3 (OCH2CH=CH2), 96.0 (JC,H
167 Hz, C-1), 81.5 (C-4), 80.4 (C-3), 77.4 (C-2), 75.2
(OCH2Ph), 67.8 (C-5 and OCH2CH=CH2), 59.0
(OCH3), 57.7 (OCH3), 17.8 (C-6). Anal. Calcd for
C18H26O5: C, 67.05; H, 8.14. Found: C, 66.98; H,
8.24.
1
13
ꢁ), 3.33 (d, JH, C 143 Hz, O13CH3-ꢁ). A solution
of the triol 4 (2.1 g, 6.3 mmol) in Ac2O±pyridine
(1:2, 30 mL) was stirred for 24 h at room tempera-
ture. The mixture was poured into ice-water
(200 mL) and the product was extracted with
CH2Cl2(2Â50 mL). The extracts were washed suc-
cessively with 1 N aq HCl, satd aq NaHCO3, satd
NaCl, combined, dried, and concentrated.
Chromatography of the residue (EtOAc±hexanes,
1:2) gave an anomeric mixture of 1,2,4-tri-O-
acetyl-3,6-di-O13C-methyl-ꢁ,ꢀ-d-glucopyranose (5)
as a white solid (1.5 g, 74%). The triacetate 5
(550 mg, 1.6 mmol) was converted to the hemi-
acetal 7 as described for the preparation of the
hemiacetal 6. The crude hemiacetal 7 (570 mg) was
then converted to the trichloroacetimidate 9 as
described for the preparation of the tri-
chloroacetimidate 8. The trichloroacetimidate 9
was puri®ed by chromatography (EtOAc±hexanes,
1:3) and was obtained as a colorless syrup (410 mg,
64%); its purity was con®rmed by NMR spectro-
scopy and it was used directly in the glycosylation
Allyl
4-O-benzyl-3-O-methyl-a-l-rhamnopyr-
anoside (12).ÐA mixture of allyl 4-O-benzyl-ꢁ-l-
rhamnopyranoside 10 (1.8 g, 6.1 mmol) and dibu-
tyltin oxide (1.8 g, 7.2 mmol) in benzene (80 mL)
was re¯uxed for 3 h with azeotropic removal of the
water. The mixture was cooled to room tempera-
ture, toluene was added and the solvents were eva-
porated. The dried residue was dissolved in DMF
(8 mL), methyl iodide (0.42 mL, 6.7 mmol) was
added dropwise and the mixture was stirred over-
night at 35±40 ꢀC. The solution was concentrated
and chromatography of the residue (EtOAc±hex-
anes, 1:1) gave the monomethyl ether 12 as a col-
reactions, [ꢁ]22 +96.5ꢀ (c 0.48, CH2Cl2). 1H
d
NMR: ꢂ 8.6 (s, C=NH), 6.48 (d, 1 H, J1,2 4 Hz, H-
1), 5.08 (dd, 1 H, J4,3+J4,5=20 Hz, H-4), 4.98 (dd,
1 H, J2,3 10 Hz, H-2), 4.01 (m, 1 H, H-5), 3.80 (td, 1
0
H, 3J3, C 6 Hz, H-3), 3.43 (m, 2 H, H-6, H-6 ), 3.46
orless syrup (1.3 g, 71%), [ꢁ]22
89ꢀ (c 0.9,
13
d
(d, 3 H, JH, C 142 Hz, O13CH3), 3.31 (d, 3 H,
CH2Cl2). 1H NMR: ꢂ 7.36 (m, 5 H, Ar), 5.88 (m, 1 H,
OCH2CH=CH2), 5.24 (m, 2 H, OCH2CH=CH2),
4.85 (d, 1 H, J1,2 2 Hz, H-1), 4.84, 4.62 (2Âd, 1 H, J
11 Hz, 2ÂOCHHPh), 4.07 (dd, 1 H, J2,3 3.5 Hz, H-
2), 4.06 (m, 2 H, OCH2CH=CH2), 3.72 (m, 1 H,
H-5), 3.59 (dd, 1 H, J3,4 9.5 Hz, H-3), 3.50 (s, 3 H,
OCH3), 3.37 (t, 1 H, J4,3+J4,5=19 Hz, H-4), 2.43
(bs, 1 H, OH), 1.30 (d, 3 H, H-6). 13C NMR: ꢂ 133.9
(OCH2CH=CH2), 138.6, 128.4, 127.9, 127.7 (Ar),
117.4 (OCH2CH=CH2), 98.3 (C-1), 81.8, 80.0 (C-
3, C-4), 75.2 (OCH2Ph), 68.0 (C-5), 67.9, 67.3 (C-2,
OCH2CH=CH2), 57.4 (OCH3), 17.9 (C-6). Anal.
Calcd for C17H24O5: C, 66.20; H, 7.86. Found: C,
66.42; H, 8.05.
1
13
1JH, C 142 Hz, O13CH3), 2.11, 2.02 (2 s, 2Â3 H,
13
2ÂCH3CO). 13C NMR: ꢂ 169.7, 169.4 (2ÂC=O),
160.7 (C=NH), 93.4 (JC,H 179.9 Hz, C-1), 90.9
(CCl3), 78.2 (C-3), 71.6 (C-2), 71.5 (C-5), 71.2 (C-
6), 69.7 (C-4), 59.9 (qd, 1J13 142 Hz, 3J13
6 Hz,
3 Hz,
C,H
C,H-3
C,H-6
O13CH3-3), 59.3 (qt, J13 142 Hz, J13
1
3
C,H
O13CH3-6), 20.8, 20.5 (2ÂCH3CO).
Allyl 4-O-benzyl-2,3-di-O-methyl-a-l-rhamnopy-
ranoside (11).ÐA solution of allyl 4-O-benzyl-ꢁ-l-
rhamnopyranoside 10 (3.2 g, 11 mmol) [29] in
DMF (20 mL) was transferred under N2 to a sus-
pension of NaH (2.0 g, 60% by weight in oil,
82 mmol) in DMF (10 mL) stirred at 0 ꢀC. After
stirring for 15 min at 0 ꢀC, methyl iodide (2 mL,
32 mmol) was added slowly to the mixture that was
then stirred for 2 h at room temperature. MeOH
(5 mL) was added to destroy the excess NaH and
the mixture was poured into ice-water (60 mL). The
product was extracted with CH2Cl2 (60 mL,
Propyl
2,3-di-O-methyl-a-l-rhamnopyranoside
(15).ÐThe benzyl ether 11 (1.1 g, 3.5 mmol) was
dissolved in EtOH±80% aq AcOH (1:2, 45 mL)
and hydrogenolyzed overnight at 52 psi over Pd/C
(10%, 0.10 g). The black solid was removed
by ®ltration and the ®ltrate was concentrated to

498
X. Wu et al./Carbohydrate Research 306 (1998) 493±503
3
13
dryness by coconcentration with toluene. Chroma-
tography (EtOAc±hexanes, 1:1) of the residue
gave the alcohol 15 as a colorless syrup (0.81 g,
3.41 (dt, 1 H, J3,4 9.5 Hz, J3,2 3.5 Hz, JH, C,
3.5 Hz, H-3), 3.36 (dt, 1 H, OCHaHbCH2CH3),
2.4±2.3 (bs, 1 H, OH), 1.60 (m, 2 H, OCH2CH2CH3),
1.30 (d, 3 H, J6,5 6 Hz, H-6), 0.92 (t, 3 H,
OCH2CH2CH3). 13C NMR: ꢂ 97.2 (1JC,H 167 Hz,
C-1), 81.2 (C-3), 76.1 (C-2), 71.8 (C-4), 69.2
(OCH2CH2CH3), 68.1 (C-5), 58.9 (1JC,H 142 Hz,
100%), [ꢁ]22
32.4ꢀ (c 0.7, CH2Cl2). H NMR:
1
d
ꢂ 4.81 (d, 1 H, J1,2 2 Hz, H-1), 3.61 (dt, 1 H,
OCHaHbCH2CH3), 3.58±3.57 (m, 2 H, H-2 and H-
5), 3.51 (t, 1 H, J4,3+J4,5=19 Hz, H-4), 3.45, 3.43
(2 s, 2Â3 H, 2ÂOCH3), 3.39 (dd, 1 H, J3,4 9.5 Hz,
J3,2 3 Hz, H-3), 3.34 (dt, 1 H, OCHaHbCH2CH3),
1.57 (m, 2 H, OCH2CH2CH3), 1.27 (d, 3 H, J6,5
6 Hz, H-6), 0.9 (t, 3 H, OCH2CH2CH3). 13C NMR:
ꢂ 97.2 (1JC,H 167 Hz, C-1), 81.3 (C-3), 76.1 (C-2),
71.8 (C-4), 69.2 (OCH2CH2CH3), 68.1 (C-5), 58.9,
56.9 (2ÂOCH3), 22.8 (OCH2CH2CH3), 17.7 (C-6),
10.6 (OCH2CH2CH3). Anal. Calcd for C11H22O5:
C, 56.38; H, 9.48. Found: C, 56.43; H, 9.52.
3JC,H-2 5 Hz, OCH3-2), 56.9 (qd, J13 142 Hz,
1
C,H
3J13
4 Hz, O13CH3-3), 22.8 (OCH2CH2CH3),
C,H-3
17.7 (C-6), 10.6 (OCH2CH2CH3). Anal. Calcd for
C1013C1H22O5: C, 56.13; H, 9.44. Found: C, 56.30;
H, 9.47.
Propyl 4-O-(2,4-di-O-acetyl-3,6-di-O-methyl-b-d -
glucopyranosyl)-2,3-di-O-methyl-a-l-rhamnopy-
ranoside (20).ÐA mixture of the acceptor 15
(192 mg, 0.82 mmol), the trichloroacetimidate 8
(415 mg, 0.95 mmol) and activated molecular sieves
(4A) in anhydrous CH2Cl2 (20 mL) was stirred for
1 h under N2. The mixture was cooled to 78 ꢀC
Propyl 2-O-methyl-3-O-13C-methyl-a-l-rhamno-
pyranoside (16).ÐAllyl 4-O-benzyl-ꢁ-l-rhamno-
pyranoside 10 (1.6 g, 5.6 mmol) was selectively
methylated at O-3 with methyl-13C iodide as
described for the preparation of the unlabeled
methyl ether 12. The dimethyl ether 13 was puri®ed
by chromatography (EtOAc±hexanes, 1:1) and
isolated as a syrup (0.94 g, 54%). A solution of 13
(0.94 g, 3.0 mmol) in DMF (4.5 mL) was trans-
ferred under N2 to a cooled (0 ꢀC) suspension of
NaH (0.31 g, 60% by weight in oil, 7.9 mmol) in
DMF (2 mL). After stirring for 30 min at 0 ꢀC,
methyl iodide (0.41 g, 6.1 mmol) was added drop-
wise and the reaction mixture was stirred under N2
for 2 h at room temperature. MeOH (2 mL) was
added to destroy the excess NaH and the reaction
mixture was poured into ice-water (10 mL). The
product was extracted with EtOAc (20 mL,
3Â10 mL), the extracts were washed with water,
combined, dried, and concentrated to give crude 14
as a syrup (1.1 g). The syrup was dissolved in
EtOH±80% aq AcOH (1:2, 45 mL) and hydro-
genolyzed overnight at 52 psi over Pd/C (10% on
charcoal, 0.13 g). More catalyst (56 mg) was added
and the reaction was allowed to proceed for 24 h.
The catalyst was removed by ®ltration through
Celite 545 and the ®ltrate was extracted with
CH2Cl2 (3Â20 mL). The extracts were washed with
satd aq NaHCO3 (2Â20 mL), combined, dried, and
concentrated. Chromatography (EtOAc±hexanes,
1:1) of the residue yielded pure 16 as a colorless
and
triethylsilyl
tri¯ate(TESOTf)
(30 ꢃL,
0.13 mmol) was added. After stirring for 15 min at
78 ꢀC, the reaction was allowed to proceed 15 min
at room temperature and quenched by addition of
triethylamine (ꢁ25 ꢃL). The molecular sieves were
removed by ®ltration and the ®ltrate was con-
centrated. Chromatography (EtOAc±hexanes, 1:1)
of the residue gave the disaccharide 20 as a color-
less oil (420 mg, 100%), [ꢁ]22
51ꢀ (c 0.7,
d
1
CH2Cl2). H NMR: ꢂ 4.98 (t, 1 H, J4,3+J4,5=
18 Hz, H-4A), 4.90 (dd, 1 H, J2,1 8 Hz, J2,3 10 Hz,
H-2A), 4.82 (d, 1 H, J1,2 2 Hz, H-1B), 4.74 (d, 1 H,
H-1A), 3.61±3.51 (m, 4 H, H-60A, H-6A, H-5B,
OCHaHbCH2CH3), 3.56 (dd, 1 H, J2,3 3 Hz, H-2B),
3.48±3.30 (m, 5 H, H-3B, H-4B, H-3A, H-5A,
OCHaHbCH2CH3), 3.48, 3.42, 3.38, 3.30(4s, 4Â3
H, 4ÂOCH3), 3.34(dd, 1H, OCHaHbCH2CH3),
2.30, 2.50 (2s, 2Â3 H, CH3CO), 1.32(m, 2H,
OCH2CH2CH3), 1.13(d, 3H, H-6B), 0.96 (t, 3 H,
CH2CH2CH3). 13C NMR: ꢂ 169.3, 168.9 (2ÂC=O),
100.9 (1JC,H 167 Hz, C-1A), 96.6 (1JC,H 167 Hz,
C-1B), 81.5, 81.3 (C-3B, C-4B), 77.6, 76.7 (C-2B,
C-6A), 73.0, 72.4, 72.0 (C-2A, C-3A, C-5A), 70.2
(C-4A), 69.3 (OCH2CH2CH3), 67.0 (C-5B), 59.6,
58.9, 58.3, 57.0 (4ÂOCH3), 22.6 (OCH2CH2CH3),
20.9, 20.8 (2ÂCH3CO), 17.7 (C-6B), 10.5
(OCH2CH2CH3). Anal. Calcd for C23H40O12: C,
54.33; H, 7.87. Found: C, 54.42; H, 8.03.
syrup (570 mg, 80% based on 14), [ꢁ]22
33.6ꢀ (c
Propyl 4-O-(2,4-di-O-acetyl-3,6-di-O-methyl-b-
d-glucopyranosyl)-2-O-methyl-3-O-13C-methyl-a-l-
rhamnopyranoside (21).ÐGlycosylation of the
acceptor 16 (162 mg, 0.69 mmol) with the trichloro-
acetimidate 8 (297 mg, 0.68 mmol) was performed
d
1
0.7, CH2Cl2). H NMR: ꢂ 4.85 (d, 1 H, J1,2 2 Hz,
H-1), 3.61 (m, 3 H, H-2, H-5, OCHaHbCH2CH3),
3.54 (t, 1 H, J4,3+J4,5=19 Hz, H-4), 3.48 (s, 3 H,
13
OCH3-2), 3.46 (d, 3 H, JH, C 141 Hz, O13CH3-3),

X. Wu et al./Carbohydrate Research 306 (1998) 493±503
499
as described for the preparation of disaccharide 20.
The disaccharide 21 was puri®ed by chromato-
graphy (EtOAc±hexanes, 1:1) and was isolated as a
acceptor 16 (58 mg, 0.25 mmol) with the trichloro-
acetimidate 9 (110 mg, 0.25 mmol) was performed
as described for the preparation of disaccharide 20.
Chromatography (EtOAc±hexanes, 1:1) gave the
1
syrup (321 mg, 93%). H NMR: ꢂ 4.98 (t, 1 H,
J4,3+J4,5=18 Hz, H-4A), 4.90 (dd, 1 H, J2,1 8 Hz,
J2,3 10 Hz, H-2A), 4.82 (d, 1 H, J1,2 2 Hz, H-1B),
4.74 (d, 1 H, H-1A), 3.59 (m, 1 H, H-5B), 3.61 (dd,
1 H, OCHaHbCH2CH3), 3.56 (dd, J2,3 3 Hz, H-2B),
3.56±3.51 (m, 2 H, H-60A and H-6A), 3.48±3.42 (m,
disaccharide 23 as a syrup (0.12 g, 100%). [ꢁ]22
d
51.5ꢀ (c 2.3, CH2Cl2). H NMR: ꢂ 4.98(t, 1 H,
1
J4,3+J4,5=18 Hz, H-4A), 4.90 (dd, 1 H, J2,1 8 Hz,
J2,3 10 Hz, H-2A), 4.82 (d, 1 H, J1,2 2 Hz, H-1B),
4.76 (d,
OCHaHbCH2CH3), 3.44 (d, 3 H, J13 141 Hz,
1
H, H-1A), 3.61 (dt,
1
1
H,
1
3 H, H-3B, H-4B, H-5A), 3.43 (d, 3 H, J13
C,H
C-H
141 Hz, O13CH3-3B), 3.48, 3.38, 3.32 (3s, 3Â3 H,
3ÂOCH3), 3.44 (t, 1 H, J3,2+J3,4=20 Hz, H-3A),
3.34 (dd, 1 H, OCHaHbCH2CH3), 2.30, 2.50 (2s,
2Â3 H, 2ÂCH3CO), 1.32 (OCH2CH2CH3), 1.13 (d,
3 H, H-6B), 0.96 (OCH2CH2CH3). 13C NMR:
ꢂ 101.0(C-1A), 96.7(C-1B), 81.5, 81.4 (C-3B, C-4B),
77.7, 76.8 (C-2B, C-6A), 73.0, 72.5, 72.1 (C-2A, C-
O13CH3), 3.38 (d, 3 H, J13 141 Hz, O13CH3),
1
C,H
1
3.32(d, 3 H, J13 142 Hz, O13CH3), 3.49 (s, 3 H,
C,H
OCH3-2B), 3.34 (dt, 1 H, OCHaHbCH2CH3), 2.10,
2.08 (2s, 2Â3 H, 2ÂCH3CO), 1.59 (m, 2 H,
OCH2CH2CH3), 1.24 (d, H-6B), 0.92 (t, 3 H,
OCH2CH2CH3). 13C NMR: ꢂ 169.6, 169.3(C=O),
101.0 (C-1A), 96.6 (C-1B), 81.5, 81.4 (C-3B, C-4B),
77.7, 76.8 (C-2B, C-6A), 73.0, 72.4, 72.1 (C-2A, C-
3A, C-5A), 70.3 (C-4A), 69.4 (OCH2CH2CH3),
3A, C-5A), 70.3 (C-4A), 69.4 (OCH CH2CH3), 67.0
(C-5B), 59.6 (OCH3-6A), 58.9 (OCH3-2B), 58.2
2
3
1
3
(OCH3-3A), 57.1 (1J13
141 Hz, J13
4 Hz,
67.0 (C-5B), 59.6 (qt, J13 141 Hz, J13
4 Hz,
C,H
C,H-3
C,H
C,6A
O13CH3-3B), 22.7 (OCH2CH2CH3), 21.0, 20.8
(2ÂCH3CO), 17.8(C-6B), 10.6 (OCH2CH2CH3).
Propyl 4-O-(2,4-di-O-acetyl-3,6-di-O-13C-methyl-
b-d-glucopyranosyl)-2,3-di-O-methyl-a-l-rhamno-
pyranoside (22).ÐGlycosylation of the acceptor 15
(55 mg, 0.24 mmol) with the trichloroacetimidate 9
(94 mg, 0.22 mmol) was performed as described for
the preparation of disaccharide 20. Disaccharide 22
was puri®ed by chromatography (EtOAc±hexanes,
O13CH3-6A), 58.9 (OCH3-2B), 58.2 (1J13
142 Hz, J13 6 Hz, O13CH3-3A), 57.1 (qd, J13
C,H
C,H
3
1
C,3A
141 Hz,
3J13
5 Hz,
O13CH3-3B),
22.7
C,3B
(OCH2CH2CH3), 23.0, 20.9 (2ÂCH3CO), 17.8 (C-
6B), 10.6 (OCH2CH2CH3). Anal. Calcd for
C2013C3H40O12: C, 54.10; H, 7.90. Found C, 54.35;
H, 7.85.
Propyl 4-O-(3,6-di-O-methyl-b-d-glucopyrano-
syl)-2,3-di-O-methyl-a-l-rhamnopyranoside (24).Ð
A solution of the protected disaccharide 20
(410 mg, 0.81 mmol) in methanolic sodium meth-
oxide (0.3 N, 4 mL) was stirred for 2 h at room
temperature and neutralized with Dowex 50W-
X8(H+) resin. The resin was ®ltered o€, rinsed
with MeOH (5 mL) and the combined supernatant
and washings were concentrated. Chromatography
(EtOAc±hexanes±MeOH, 6:6:1) of the residue gave
the disaccharide 24 that crystallized on standing
1:1) and was isolated as a syrup (78 mg, 71%),
50.3ꢀ (c 2.3, CH2Cl2). 1H NMR: ꢂ 4.98 (t, 1
22
[ꢁ]d
H, J4,3+J4,5=18 Hz, H-4A), 4.90 (dd, 1 H, J2,1
8 Hz, J2,3 10 Hz, H-2A), 4.82 (d, 1 H, J1,2 2 Hz, H-
1B), 4.76 (d, 1 H, H-1A), 3.48 (s, 3 H, OCH3), 3.38
1
(d, 3 H, J13 141 Hz, O13CH3), 3.32 (d, 3 H,
C,H
1J13 142 Hz, O13CH3), 3.49 (s, 3 H, OCH3-2B),
C,H
3.34 (dt, 1 H, OCHaHbCH2CH3), 2.10, 2.08 (2s,
2Â3 H, 2ÂCH3CO), 1.59 (m, 2 H, OCH2CH2CH3),
1.24 (d, 3 H, H-6B), 0.92 (t, 3 H, OCH2CH2CH3).
13C NMR: ꢂ 169.6, 169.3 (2ÂC=O), 101.0 (C-1A),
96.6 (C-1B), 81.5, 81.4 (C-3B, C-4B), 77.7, 76.8 (C-
2B, C-6A), 73.0, 72.4, 72.1 (C-2A, C-3A, C-5A),
(291 mg, 85%), mp 52±54 ꢀC, [ꢁ]22
53ꢀ (c 0.6,
d
46.1 (c 1.2, CHCl3)]. H
ꢀ
1
CH2Cl2) [lit [6]., [ꢁ]26
d
NMR: ꢂ 4.81 (d, 1H, J1,2 2 Hz, H-1B), 4.40 (d, 1H,
J1,2 8 Hz, H-1A), 3.67 (s, 3H, OCH3), 3.64 (H-5B),
3.63 (m, 2H, H-6A, H-60A), 3.62 (m, 3H, H-2B, H-
3B, H-4B), 3.59 (dt, 1H, OCHaHbCH2CH3), 3.52
(t, 1H, J4,3+J4,5=18 Hz, H-4A), 3.48 (s, 3H,
OCH3), 3.46 (s, 3H, OCH3), 3.41 (m, 1H, H-5A),
3.38 (s, 3H, OCH3), 3.15 (t, 1H, J3,2+J3,4=20 Hz,
H-3A), 3.35 (dt, 1H, OCHaHbCH2CH3), 1.57
(OCH2CH2CH3), 1.34 (d, 3H, H-6B), 0.90
(OCH2CH2CH3). 13C NMR: ꢂ 105.6 (1JC,H 159 Hz,
C-1A), 96.8(1JC,H 168 Hz, C-1B), 85.6 (C-3A), 81.8
(C-3B), 80.7 (C-4B), 76.0 (C-2B), 75.0 (C-2A), 74.2
1
70.7 (C-4A), 69.4, 67.0 (C-5B), 59.6 (qt, J13
C,H
141 Hz, 3J13
58.2 (qd, J13 142 Hz, J13
4 Hz, O13CH3-6A), 58.9 (OCH3-2B),
1C,H-6A
3
6 Hz, O13CH3-
C,H
C,H-3A
3A), 58.0 (OCH3-3B), 22.7 (OCH2CH2CH3), 21.0,
20.9 (CH3CO), 17.8 (C-6B), 10.6 (OCH2CH2CH3).
Anal. Calcd for C2113C2H40O12: C, 54.10; H, 7.91.
Found: C, 54.21; H, 8.09.
Propyl 4-O-(2,4-di-O-acetyl-3,6-di-O-13C-methyl-
b-d-glucopyranosyl)-2-O-methyl-3-O-13C-methyl-a-
l-rhamnopyranoside (23).ÐGlycosylation of the

500
X. Wu et al./Carbohydrate Research 306 (1998) 493±503
(C-5A), 72.8 (C-6A), 71.2 (C-4A), 69.3
(OCH2CH2CH3), 67.5 (C-5B), 60.4, 59.5, 59.0,
56.4(4ÂOCH3), 22.7 (OCH2CH2CH3), 17.5 (C-
6B), 10. 6 (OCH2CH2CH3). Anal. Calcd for
C19H36O10: C, 53.75; H, 8.56. Found: C, 53.64; H,
8.62.
C-1A), 96.9 (1JC,H 167 Hz, C-1B), 85.6 (C-3A), 81.9
(C-3B), 80.7 (C-4B), 76.0 (C-2B), 75.1 (C-2A),
74.1 (C-5A), 72.9 (C-6A), 71.3 (C-4A), 69.3
1
(OCH2CH2CH3), 67.5 (C-5B), 60.4 (qd, J13
142 Hz, 3J
C,H
5 Hz, O13CH3-3A), 59.6 (qt, 1J
13C,H-3A
13C,H
3
142 Hz, J13
4 Hz, O13CH3-6A), 59.0 (OCH3-
C,H-6A
Propyl 4-O-(3,6-di-O-methyl-b-d-glucopyrano-
syl)-2-O-methyl-3-O-13C-methyl-a-l-rhamnopyrano-
side (25).ÐDeacetylation of disaccharide 21
(193 mg, 0.38 mmol) was performed as described
for the deprotection of disaccharide 20. Chroma-
tography (EtOAc±hexanes±MeOH, 4:4:1) gave the
2B), 56.4(OCH3-3B), 22.7 (OCH2CH2CH3), 17.5
(C-6B), 10.6 (OCH2CH2CH3).. Anal. Calcd for
C1713C2H36O10: C, 53.50; H, 8.52. Found: C, 53.70;
H, 8.40.
Propyl 4-O-(3,6-di-O-13C-methyl-b-d-glucopyr-
anosyl)-2-O-methyl-3-O-13C-methyl-a-l-rhamno-
pyranoside (27).ÐDeacetylation of disaccharide 23
(66 mg, 0.13 mmol) was performed as described for
the deprotection of disaccharide 20. Chromato-
graphy (EtOAc±hexanes±MeOH, 6:6:1) gave the
disaccharide 27 as a colorless syrup (58 mg, 100%),
disaccharide 25 asꢀ a colorless syrup (161 mg,
1
100%), [ꢁ]22
4.81 (d, 1H, J1,2 1.5 Hz, H-1B), 4.40 (d, 1H, J1,2
51.6 (c 1.2, CH2Cl2). H NMR: ꢂ
d
7.5 Hz, H-1A), 3.45 (d, 1J13 142 Hz, O13CH3-3B),
C,H
3.66 (s, 3H, OCH3), 3.62 (m, 7H, overlapped, H-
6A, H-60A, H-2B, H-3B, H-4B, H-5B,
OCHaHbCH2CH3), 3.53 (t, J4,3+J4,5=20 Hz, H-
4A), 3.47 (s, 3H, OCH3), 3.46±3.37(m, 2H, over-
lapped, H-2A, H-5A), 3.37 (s, 3H, OCH3), 3.35 (dt,
1H, OCHaHbCH2CH3), 3.15 (t, 1H, J2,3+J3,4=
18 Hz, H-3A), 1.57 (m, 2H, OCH2CH2CH3), 1.34
(d, 3H, H-6B), 0.90 (t, 3H, OCH2CH2CH3). 13C
NMR: ꢂ 105.6 (1JC,H 161 Hz, C-1A), 96.9(1JC,H
168 Hz, C-1B), 85.6 (C-3A), 81.9 (C-3B), 80.7 (C-
4B), 76.1 (C-2B), 75.1 (C-2A), 74.2 (C-5A), 72.9
(C-6A), 71.2 (C-4A), 69.3 (OCH2CH2CH3), 67.6
(C-5B), 60.4, 59.6, 59.0 (3ÂOCH3), 56.4 (qd,
ꢀ
1
[ꢁ]22
44 (c 0.8, CH2Cl2). H NMR: ꢂ 4.82 (d,
d
1H, J1,2 1.5 Hz, H-1B), 4.40 (d, 1H, J1,2 8 Hz, H-
1A), 3.68±3.48 (m, 6H, overlapped, H-6A, H-60A,
H-2B, H-3B, H-4B, H-5B), 3.59 (dt, 1H,
OCHaHbCH2CH3), 3.53 (m, 1H, H-4A), 3.41 (m,
1
C,H
2H, H-2A, H-5A), 3.67 (d, 3H, J13
1
C,H
142 Hz,
O13CH3), 3.46 (d, 3H, J13 142 Hz, O13CH3),
1
3.38 (d, 3H, J13 142 Hz, O13CH3), 3.48 (s, 3H,
C,H
OCH3), 3.35(dt, 1H, OCHaHbCH2CH3), 3.16 (dt,
3
C,H
1H, J3,2+J3,4=9.0 Hz, J13 5 Hz, H-3A), 1.57
(OCH2CH2CH3), 1.34 (d, 3H, H-6B), 0.91
(OCH2CH2CH3). 13C NMR: ꢂ 105.7 (1JC,H 158 Hz,
C-1A), 96.8 (1JC,H 168 Hz, C-1B), 85.6 (C-3A), 81.9
(C-3B), 80.7 (C-4B), 76.0(C-2B), 75.1 (C-2A),
74.1 (C-5A), 72.9 (C-6A), 71.3 (C-4A), 69.3
1J13
142 Hz, 3J13
3 Hz, O13CH3-3B),
C,H
C,H-3B
22.8 (OCH2CH2CH3), 17.5 (C-6B), 10.6
(OCH2CH2CH3). Anal. Calcd for C1813C1H36O10:
C, 53.62; H, 8.54. Found: C, 53.49; H, 8.67.
Propyl 4-O-(3,6-di-O-13C-methyl-b-d-glucopyr-
anosyl)-2,3-di-O-methyl-a-l -rhamnopyranoside
(26).ÐDeacetylation of disaccharide 22 (78 mg,
0.15 mmol) was performed as described for the
deprotection of disaccharide 20. Chromatography
(EtOAc±hexanes±MeOH, 6:6:1) gave the dis-
1
(OCH2CH2CH3), 67.5 (C-5B), 60.4 (qd, J13
142 Hz, 3J13
C,H
5 Hz, O13CH3-3A), 59.6 (qt, 1J13
C,H-3A C,H
3
142 Hz, J13
2B), 56.4 (qd, J13
4 Hz, O13CH3-6A), 59.0 (OCH3-
C,H-6A
1
3
142 Hz, J13
3 Hz,
C,H
C,H-3B
O13CH3-3B), 22.8 (OCH2CH2CH3), 17.5(C-6B),
10.6
(OCH2CH2CH3).
Anal.
Calcd
for
C1613C3H36O10: C, 53.37; H, 8.50. Found: C, 53.55;
H, 8.54.
accharide 26 as a colorless syrup (58 mg, 89%),
45ꢀ (c 0.6, CH2Cl2). H NMR: ꢂ 4.82 (d,
1
[ꢁ]22
Allyl 2-O-(4-O-acetyl-2,3-di-O-methyl-a-l-rha-
mnopyranosyl)-4-O-benzyl-3-O-methyl-a-l-rhamno-
pyranoside (28).ÐA solution of the allyl glycoside
11 (2.1 g, 6.7 mmol) in 95% aq AcOH (120 mL)
containing palladium (II) chloride (1.4 g,
8.0 mmol), and NaOAc (1.6 g, 20 mmol) was stirred
for 48 h at room temperature. The reaction mixture
was ®ltered, extracted with CH2Cl2 (3Â50 mL),
and the extracts were washed successively with
water (2Â40 mL), satd aq NaHCO3 (4Â40 mL),
satd NaCl (2Â40 mL), then combined, dried and
concentrated. Chromatography (EtOAc±hexanes,
d
1H, J1,2 1.5 Hz, H-1B), 4.40 (d, 1H, J1,2 8 Hz, H-
1A), 3.68±3.48 (m, 6H, overlapped, H-6A, H-60A,
H-2B, H-3B, H-4B, H-5B), 3.59 (dt, 1H,
OCHaHbCH2CH3), 3.53 (H-4A), 3.41(m, 2H,
1
overlapped, H-2A, H-5A), 3.67 (d, 3H, J13
142 Hz, O13CH3), 3.38 (d, 3H, J13
C,H
1
142 Hz,
C,H
O13CH3), 3.48 (s, 3H, OCH3), 3.46 (s, 3H, OCH3),
3.35 (dt, 1H, OCHaHbCH2CH3), 3.16 (tt, 1H,
J3,2+J3,4=18 Hz, 3J13
5 Hz, H-3A), 1.57
C,H
(OCH2CH2CH3), 1.34 (d, 3H, H-6B), 0.91
(OCH2CH2CH3). 13C NMR: ꢂ 105.7 (1JC,H 160 Hz,

X. Wu et al./Carbohydrate Research 306 (1998) 493±503
501
1:1) of the residue gave an anomeric mixture 4-O-
benzyl-2,3-di-O-methyl-ꢁ,ꢀ-l-rhamnose (17) as a
colorless syrup (1.7 g, 99%). Crystallization from
EtAc±hexanes (1:8) gave white crystals that were
estimated by NMR to be a 2:1 mixture of the ꢁ-
(542 mg, 97%) that was isolated as white crystals
from EtOH-hexanes, mp 109±110 ꢀC, [ꢁ]22 65.6ꢀ
d
(c 0.7, CH2Cl2). 1H NMR: ꢂ 7.36 (m, 5 H, Ar), 5.87
(m, 1 H, OCH2CH=CH2), 5.23 (m, 2 H,
OCH2CH=CH2), 5.10 (d, 1 H, J1,2 2 Hz, H-1B),
5.03 (t, 1 H, J4,3+J4,5=20 Hz, H-4B), 4.88 (d, 1 H,
J 11 Hz OCHHPh), 4.77 (d, 1 H, J1,2 2 Hz, H-1C),
4.63 (d, 1 H, OCHHPh), 4.06 (dd, 1 H, J2,3 3 Hz,
H-2C), 4.04 (m, 2 H, OCH2CH=CH2), 3.72 (dd, 1
H, J2,3 3 Hz, H-2B), 3.76 (m, 1 H, H-5B), 3.69 (m, 1
H, H-5C), 3.62 (dd, 1 H, J3,4 10 Hz, H-3C), 3.56
(dd, 1 H, J3,4 10 Hz, H-3B), 3.52, 3.48, 3.44 (3s,
3Â3H, 3ÂOCH3), 3.37 (t, 1 H, J4,3+J4,5=20 Hz,
H-4C), 2.05 (s, 3 H, CH3CO), 1.30 (d, 3 H, H-6C),
1.15 (d, 3 H, H-6B). 13C NMR: ꢂ 169.9 (C=O),
133.8 (OCH2CH=CH2), 138.6, 128.4, 128.0, 127.7
(Ar), 117.4 (OCH2CH=CH2), 99.2 (1JC,H 171 Hz,
C-1B), 98.1 (1JC,H 170 Hz, C-1C), 81.9 (C-3C), 80.2
(C-4C), 78.7 (C-3B), 75.0 (OCH2Ph), 77.1 (C-2B),
74.1 (C-2C), 73.1 (C-4B), 67.9, 67.8, 67.1 (C-5B, C-
5C, OCH2CH=CH2), 59.1, 57.9, 57.8(2ÂOCH3),
21.0 (CH3CO), 17.9 (C-6C), 17.5 (C-6B). Anal.
Calcd for C27H40O10: C, 61.80; H, 7.70. Found: C,
62.01; H, 7.85.
1
and ꢀ-pyranoses. H NMR: ꢂ 7.32 (m, 5 H, Ar),
5.26 (bs, 1 Hꢁ, H-1ꢁ), 4.90, 4.89, 4.61, 4.60 (4 d, 2
H ꢁ, 2 Hꢀ, OCH2Ph), 4.65 (bs, 1 Hꢀ, H-1ꢀ), 3.43
(dd, 1 Hꢁ, J4,3+J4,5=18 Hz, H-4ꢁ), 3.38 (dd, 1
Hꢀ, J4,3+J4,5=18 Hz, H-4ꢀ), 1.32 (d, 1 Hꢀ, J5,6
6 Hz, H-6ꢀ), 1.28 (d, 1 Hꢁ, J6,5 6 Hz, H-6ꢁ). 13C
NMR: ꢂ 138.8, 128.4, 128.3, 127.9, 127.8, 127.6
(Ar), 93.6 (JC,H 162 Hz, C-1ꢀ), 92.0 (JC,H 172 Hz,
C-1ꢁ), 61.8 (OCH3-ꢀ), 59.2 (OCH3-ꢁ), 58.1
(OCH3-ꢀ), 57.8 (OCH3-ꢁ), 18.0 (C-6ꢁ), 17.9 (C-
6ꢀ). The anomeric mixture 17 (1.6 g, 6.0 mmol)
was hydrogenolyzed as described for the hydro-
genolysis of 14. Chromatography (EtAc±hexanes±
MeOH, 4:4:1) gave the hemiacetal 18 as a syrup
(1.1 g, 90%). Compound 18 (0.88 g, 4.6 mmol) was
acetylated as described for the preparation of 4 to
give 1,4-di-O-acetyl-2,3-di-O-methyl-ꢁ,ꢀ-l-rham-
nopyronose (19)
that, after chromatography
(EtAc±hexanes, 1:1), gave an ꢁ:ꢀ (7:1) mixture as a
1
syrup (0.97 g, 76%). H NMR: ꢂ 6.17 (d, 1 Hꢁ,
Allyl 2-O-(2,3-di-O-methyl-a-l-rhamnopyrano-
syl)-4-O-benzyl-3-O-methyl-a-l-rhamnopyrano-side
(29).ÐDeacetylation of disaccharide 28 (397 mg,
0.76 mmol) was performed as described for the
deprotection of disaccharide 20. Chromatography
(EtOAc±hexanes±MeOH, 4:8:1) gave the dis-
accharide 29 as a colorless syrup (242 mg, 66%),
J1,2 2 Hz, H-1ꢁ), 5.60 (d, 1 Hꢀ, J1,2 1 Hz, H-1ꢀ),
5.08 (t, 1 Hꢁ, J4,3 10 Hz, J4,5 10 Hz, H-4ꢁ), 4.99 (t,
1 Hꢀ, J4,3 10 Hz, J4,5 10 Hz, H-4ꢀ), 3.79 (m, 1 Hꢁ,
H-5ꢁ), 3.75 (dd, 1 Hꢀ, J2,3 3 Hz, H-2ꢀ), 3.61 (dd, 1
Hꢁ, J2,3 3 Hz, H-2ꢁ), 3.59 (s, 3 Hꢀ, OCH3), 3.54
(dd, 1 Hꢁ, H-3ꢁ), 3.52 (s, 3 Hꢁ, OCH3), 3.47 (m,
Hꢀ, H-5ꢀ), 3.43 (s, 3 Hꢁ, OCH3), 3.39 (s, 3 Hꢀ,
OCH3), 3.28 (dd, 1 Hꢀ, H-3ꢀ), 2.65, 2.42 (2s, 2Â3
Hꢁ, CH3CO), 2.13, 2.05 (2s, 2Â3 Hꢀ, CH3CO),
1.91 (d, 3 Hꢁ, J6,5 6 Hz, H-6ꢁ), 1.20 (d, 3 Hꢀ, J6,5
6 Hz, H-6ꢀ). 13C NMR: ꢂ 169.7, 168.9, 169.1
(C=O), 93.0 (C-1ꢀ), 91.3 (C-1ꢁ), 81.3 (C-3ꢀ), 78.5
(C-3ꢁ), 76.2 (C-2ꢀ), 76.0 (C-2ꢁ), 72.1 (C-4ꢀ), 7.20
(C-4ꢁ), 7.15 (C-5ꢀ), 69.2 (C-5ꢁ), 61.4, 59.2, 57.7,
57.8 ()CH3), 29.6, 21.0, 20.9 (CH3CO), 17.5 (C-6ꢁ),
17.4 (C-6ꢀ). A mixture of the acceptor 12 (327 mg,
1.1 mmol), the donor 19 (333 mg, 1.2 mmol) and
activated molecular sieves (4A) in anhydrous
CH2Cl2 (50 mL) was stirred for 1 h under N2 and
BF3-Et2O (60 ꢃL, 0.22 mmol) was added to the
mixture. The reaction was allowed to proceed for
16 h at room temperature and was quenched by
addition of NEt3 (ꢁ25 ꢃL). The molecular sieves
were removed by ®ltration, rinsed with CH2Cl2
(10 mL), and the combined supernatant and wash-
ings were concentrated. Chromatography (EtOAc±
hexanes, 1:1) of the residue gave disaccharide 28
ꢀ
1
[ꢁ]22
62.8 (c 0.8, CH2Cl2). H NMR: ꢂ 7.32 (m,
d
5 H, Ar), 5.87 (m, 1 H, OCH2CH=CH2), 5.22 (m,
2 H, OCH2CH=CH2), 5.13 (d, 1 H, J1,2 1.5 Hz, H-
1B), 4.87 (d, 1 H, J 11 Hz, OCHHPh), 4.78 (d, 1 H,
J1,2 1.5 Hz, H-1C), 4.63 (d, 1 H, OCHHPh), 4.07
(dd, 1 H, J2,3 3 Hz, H-2C), 4.04 (m, 2 H,
OCH2CH=CH2), 3.73 (dd, 1 H, J2,3 3 Hz, H-2B),
3.68 (m, 2 H, H-5B, H-5C), 3.62 (dd, 1 H, J3,4
9.5 Hz, H-3C), 3.56 (t, 1 H, J4,3+J4,5=19 Hz, H-
4B), 3.50, 3.49 (2s, 3 H and 6 H, 3ÂOCH3), 3.45 (dd,
J3,4 9.5 Hz, H-3B), 3.36 (t, 1 H, J4,3+J4,5=19 Hz,
H-4C), 1.30 (d, 3 H, H-6C), 1.29 (d, 3 H, H-6B). 13C
NMR: ꢂ 133.8 (OCH2CH=CH2), 138.7, 128.3, 128,
127.7 (Ar), 117.4 (OCH2CH=CH2), 98.9 (1JC,H
163 Hz, C-1B), 98.1 (1JC,H 165 Hz, C-1C), 82.0 (C-
3C), 80.9 (C-3B), 80.2 (C-4C), 76.0 (C-2B), 75.0
(OCH2Ph), 73.7 (C-2C), 71.7 (C-4B), 68.7, 67.9,
67.8 (C-5B, C-5C, OCH2CH=CH2), 58.8 (OCH3-
2B), 57.9 (OCH3-3C), 57.0 (OCH3-3B), 18.0, 17.7
(C-6B, C-6C). Anal. Calcd for C25H38O9: C, 62.21;
H, 7.95. Found: C, 62.00; H, 8.03.

502
X. Wu et al./Carbohydrate Research 306 (1998) 493±503
Allyl 2-O-[4-O-(2,4-di-O-acetyl-3,6-di-O-methyl-
H, Ar), 5.85 (m, 1 H, OCH2CH=CH2), 5.21 (m, 2
H, OCH2CH=CH2), 5.11 (d, J1,2 2 Hz, H-1B),
4.86 (d, 1H, J 11 Hz, OCHHPh), 4.72 (d, 1 H, J1,2
2 Hz, H-1C), 4.62 (d, 1 H, OCHHPh), 4.40 (d, 1H,
J1,2 8 Hz, H-1A), 4.00 (m, 2 H, OCH2CH=CH2),
4.04 (dd, 1 H, J2,3 3 Hz, H-2C), 3.74 (dd, 1 H, J2,3
3 Hz, H-2B), 3.67±3.50 (m, 6 H, H-6A0, H-6A, H-
3B, H-4B, H-5B, H-5C), 3.67 (m, 1 H, H-3C), 3.55
(m, 1 H, H-4A), 3.44 (m, 1 H, H-2A), 3.42 (m, 1 H,
H-5A), 3.67, 3.50, 3.49, 3.48, 3.39 (5s, 5Â3H,
5ÂOCH3), 3.32 (t, 1 H, J4,3+J4,5=18 Hz, H-4C),
3.19 (t, 1 H, J3,4+J3,2=18 Hz, H-3A), 1.32,
ꢀ-d-glucopyranosyl)-2,3-di-O-methyl-a-l-rhamno-
pyranosyl]-4-O-benzyl-3-O-methyl-a-l-rhamnopyr-
anoside (30).ÐA mixture of the acceptor 29
(211 mg, 0.44 mmol), the trichloroacetimidate 8
(237 mg, 0.54 mmol) and activated molecular sieves
(4A) in anhydrous CH2Cl2 (20 mL) was stirred for
5 h under N2. The mixture was cooled to 78 ꢀC
and TESOTf (20 ꢃL, 0.08 mmol) was added. After
stirring for 20 min at 78 ꢀC, the reaction was
allowed to proceed for 30 min at room temperature
and was quenched by addition of triethylamine
(ꢁ25 ꢃL). The molecular sieves were removed by
®ltration, rinsed with CH2Cl2 (10 mL), and the
combined supernatant and washings were con-
centrated. Chromatography (EtOAc±hexanes±
MeOH, 4:8:1) of the residue gave the disaccharide
1.25 (H-6B, H-6C). 13C NMR:
ꢂ
133.8
(OCH2CH=CH2), 138.6, 128.3, 127.9, 127.7 (Ar),
117.4 (OCH2CH=CH2), 105.5 (1JC,H 161 Hz, C-
1A), 98.5 (1JC,H 171 Hz, C-1B), 98.0 (1JC,H 170 Hz,
C-1C), 85.5 (C-3A), 82.0, 81.5, 80.3, 80.2 (C-3B, C-
4B, C-3C, C-4C), 75.9, 75.0 (C-2B, C-5A), 74.0
(OCH2Ph), 73.8 (C-2A), 73.4 (C-2C), 72.9 (C-6A),
71.2 (C-4A), 68.1, 67.9, 67.8 (C-5B, C-5C,
OCH2CH=CH2), 60.3, 59.6, 58.8, 57.9, 56.4
(5ÂOCH3), 18.0, 17.5 (C-6B, C-6C). Anal. Calcd
for C33H52O14: C, 58.90; H, 7.81. Found: C, 58.60;
H, 8.08.
Propyl 2-O-[4-O-(3,6-di-O-methyl-b-d-glucopyr-
anosyl)-2,3-di-O-methyl-a-l-rhamnopyranosyl]-3-
O-methyl-a-l-rhamnopyranoside (32).ÐThe tri-
saccharide 31 (238 mg, 0.35 mmol) was dissolved in
a mixture of 80% aq AcOH±EtOH (0.8:1, 18 mL)
and hydrogenolyzed for 6 h at 52 psi in the pre-
sence of 10% Pd/C catalyst (78 mg). More catalyst
(30 mg) was added and the reaction was allowed to
proceed at 52 psi for 3 h. The catalyst was removed
by ®ltration and the ®ltrate co-concentrated with
toluene. The dry residue was dissolved in CH2Cl2
(30 mL) and the solution was washed successively
with satd aq NaHCO3 (20 mL), satd aq NaCl
(20 mL), dried, and concentrated. Chromato-
graphy (EtOAc±hexanes±MeOH, 4:4:1) of the
30 as a colorless oil (330 mg, 100%), [ꢁ]22
63.7ꢀ
d
(c 0.3, CH2Cl2). 1H NMR: ꢂ 7.35 (m, 5 H, Ar), 5.87
(m, 1 H, OCH2CH=CH2), 5.23 (m, 2 H,
OCH2CH=CH2), 5.17 (d, J1,2 2 Hz, H-1B), 4.98 (t,
1 H, J4,3+J4,5=19 Hz, H-4A), 4.89(dd, 1 H, J2,1
8 Hz, J2,3 10 Hz, H-2A), 4.86 (d, 1 H, J 11 Hz,
OCHHPh), 4.76 (d, 1 H, H-1A), 4.74 (d, 1 H, J1,2
2 Hz, H-1C), 4.64 (d, 1 H, OCHHPh), 4.11 (m, 2
H, OCH2CH=CH2), 4.10 (dd, 1 H, J2,3 3 Hz, H-
2C), 3.73±3.56 (m, 6 H, H-6A0, H-6A, H-2B, H-5B,
H-3C, H-5C), 3.50±3.47 (m, 2 H, H-3B, H-4B),
3.50, 3.48, 3.47, 3.38, 3.32 (5s, 5Â3 H, 5ÂOCH3),
3.40±3.38 (m, 2 H, H-3A, H-5A), 3.37 (t, 1 H, J
8 Hz, J 7 Hz, H-4C), 2.70, 2.40 (2s, 2Â3 H,
2ÂCH3CO), 1.32, 1.25 (m, 2 H, H-6B, H-6C). 13C
NMR:
ꢂ
169.6, 169.1 (2ÂC=O), 133.8
(OCH2CH=CH2), 138.7, 128.3, 128.0, 127.7 (Ar),
117.5 (OCH2CH=CH2), 100.9 (C-1A), 98.2, 98.1
(C-1B, C-1C), 82.3 (C-3C), 81.5, 80.9 (C-3B, C-
4B), 80.2 (C-4C), 77.5, 76.9 (C-2B, C-6A), 75.0
(OCH2Ph), 73.1, 72.8, 72.3, 72.2 (C-2A, C-3A, C-
5A, C-2C), 70.2 (C-4A), 67.9, 67.8, 67.7 (C-5B, C-
5C, OCH2CH=CH2), 59.6, 58.87, 58.1, 57.9, 57.3
(5 x OCH3), 21.0, 20.9 (2ÂCH3CO), 18.0, 17.8 (C-
6B, C-6C). Anal. Calcd for C37H56O16: C, 58.71;
H, 7.47. Found: C, 58.49; H, 7.37.
residue gave the trisaccharide 32 as a syrup (0.19 g,
46ꢀ (c 1, CH2Cl2). H NMR: Ã 5.06
1
90%). [ꢁ]22
d
(d, J1,2 2 Hz, H-1B), 4.70 (d, J1,2 2 Hz, H-1C), 4.40
(d, J1,2 8 Hz, H-1A), 4.05 (dd, J2,1 2 Hz, J2,3 2.5 Hz,
H-2C), 3.70 (m, 2 H, H-2B, H-5B), 3.67 (s, 3 H,
OCH3-3A), 3.64 (m, 1 H, H-5C), 3.62 (m, 1H, H-
4B), 3.61(m, 1 H, H-3B), 3.53 (t, 1 H, H-4A), 3.50
(t, 1H, H-4C), 3.48 (s, 3H, OCH3-2B), 3.47 (s, 3H,
OCH3-3C), 3.46 (s, 3H, OCH3-3B), 3.43 (m, 1 H,
H-3C), 3.40 (m, 2 H, H-2A, H-5A), 3.38 (s,
3H, OCH3-6A), 3.15 (t, J 9.5 Hz, H-3A), 3.59
(dd, 1 H, OCHaHbCH2CH3), 3.34 (dd, 1 H,
OCHaHbCH2CH3), 3.58 (m, 2H, H-6A, H-60A),
Allyl 2-O-[4-O-(3,6-di-O-methyl-b-d-glucopyr-
anosyl)-2,3-di-O-methyl-a-l-rhamnopyranosyl]-4-
O-benzyl-3-O-methyl-a-l-rhamnopyranoside (31).Ð
Deacetylation of trisaccharide 30 (371 mg,
0.44 mmol) was performed as described for the
deprotection of disaccharide 20. Chromatography
(EtOAc±hexanes±MeOH, 4:4:1) gave the tri-
saccharideꢀ 31 as a colorless syrup (214 mg, 72%),
[ꢁ]22
62 (c 0.4, CH2Cl2). 1H NMR: ꢂ 7.43 (m, 5
d

X. Wu et al./Carbohydrate Research 306 (1998) 493±503
503
1.59 (m, 2 H, OCH2CH2CH3), 1.32, 1.25(2d,
2Â3H, H-6B, H-6C), 0.92 (t, 3H, OCH2CH2CH3).
13C NMR: ꢂ 105.6 (1JC,H 158 Hz, C-1A), 99.1
(1JC,H 169 Hz, C-1C), 98.3 (1JC,H 170 Hz, C-1B),
85.6 (C-3A), 81.9 (C-3C), 81.6 (C-3B), 80.3 (C-4B),
75.9 (C-2B), 75.1 (C-2A), 74.2 (C-5A), 72.9 (C-6A),
72.2 (C-2C), 72.0 (C-4C), 71.2 (C-4A), 69.2
(OCH2CH2CH3), 68.2 (overlapped, C-5B, C-5C),
60.4 (OCH3-3A), 59.6 (OCH3-6A), 59.0 (OCH3-
2B), 57.5 (OCH3-3C), 56.5 (OCH3-3B), 22.7
(OCH2CH2CH3), 17.7 (C-6C), 17.6 (C-6B), 10.6
(OCH2CH2CH3). Anal. Calcd for C26H48O14: C,
53.40; H, 8.29. Found: C, 53.20; H, 8.28.
[15] J.-R. Marino-Albernas, V. Verez-Bencomo, L.
Gonzalez-Rodriguez, and C. S. Perez-Martinez,
Carbohydr. Res., 165 (1987) 197±206.
[16] D. Chatterjee, S.N. Cho, C. Stewart, J.T. Douglas,
T. Fujiwara, and P.J. Brennan, Carbohydr. Res.,
183 (1988) 241±260.
[17] J. Marino-Albernas, V. Verez-Bencomo, L. Gon-
zalez-Rodriguez, C. S. Perez-Martinez, E. Gon-
zales-Abreu Castell, and A. Gonzales-Segredo,
Carbohydr. Res., 183 (1988) 175±182.
[18] K. Bock, T. Hvidt, J. Marino-Albernas, and V.
Verez-Bencomo, Carbohydr. Res., 200 (1990) 33±
45.
[19] K.J. Neurohr, H.H. Mantsch, N.M. Young, and
D.R. Bundle, Biochemistry, 21 (1982) 498±503.
[20] L. Poppe and H. van. Halbeek, J. Magn. Reson.,
92 (1991) 636±641.
[21] M.J. King-Morris and A.S. Serianni, J. Am. Chem.
Soc., 109 (1987) 3501±3508.
[22] C.A. Podlasek, J. Wu, W.A. Stripe, P.B. Bondo,
and A.S. Serianni, J. Am. Chem. Soc., 117 (1995)
8635±8644.
Acknowledgements
We are grateful to the Natural Sciences and
Engineering Research Council of Canada for
®nancial support.
[23] T. Church, I. Carmichael, and A.S. Serianni, Car-
bohydr. Res., 280 (1996) 177±186.
[24] W.L. Jorgensen, Science, 254 (1991) 954±955.
[25] M.K. Rosen, S.W. Michnick, T.J. Wandless, and
S.L. Schreiber, J. Org. Chem., 56 (1991) 6262±
6264.
References
[1] S.W. Hunter and P.J. Brennan, J. Bacteriol., 147
(1981) 728±735.
[26] J.-R Marino-Albernas, Ph.D. Thesis, University of
Havana, Cuba, 1991.
[2] S.W. Hunter, T. Fujiwara, and P.J. Brennan, J.
Biol. Chem., 257 (1982) 15072±15078.
[27] T.M. Slaghek, A.H. van Oijen, A.A.M. Maas, J.P.
Kamerling, and F.G. Vliegenthart, Carbohydr.
Res., 207 (1990) 237±248.
[28] R.R. Schmidt, Angew. Chem. Int. Ed. Engl., 25
(1986) 212±235.
[29] B.M. Pinto, D.G. Morissette, and D.R. Bundle, J.
Chem. Soc., Perkin Trans., 1, (1987) 9±14.
[30] C. Auge, S. David, and A. Veyrieres, J. Chem.
Soc., Chem. Commun., (1976) 375±376.
[3] S.N. Payne, P. Draper, and R.J.W. Rees, Int. J.
Lepr., 50 (1982) 220±221.
[4] S.J. Brett, P. Draper, S.N. Payne, and R.J.W.
Rees, Clin. Exp. Immunol., 52 (1983) 271±279.
[5] D.B. Young, S. Dissanayake, R.A. Miller, S.R.
Khanolkar, and T.M. Buchanan, J. Infect. Dis.,
149 (1984) 870±873.
[6] R. Gigg, S. Payne, and R. Contant, J. Carbohydr.
Chem., 2 (1983) 207±223.
[31] S. Sato, Y. Ito, T. Nukada, Y. Nakahara, and T.
Ogawa, Carbohydr. Res., 167 (1987) 197±210.
[32] (a) K. Bock and C. Pedersen, Adv. Carbohydr.
Chem. Biochem., 41 (1983) 27±66 ; (b) K. Bock, C.
Pedersen, and H. Pedersen, Adv. Carbohydr. Chem.
Biochem., 42 (1984) 193±225; (c) K. Bock, and C.
Pedersen, J. Chem. Soc. Perkin Trans., 2 (1974)
293±297.
[33] A. Bax, R.H. Gri€ey, and B.L. Hawkins, J. Magn.
Res., 55 (1983) 301±315.
[34] A. Bax and S. Subramanian, J. Magn. Res, 67
(1986) 565±569.
[35] D. R. Bundle, T. Iversen, and S. Josephson, Am.
Laboratory, 12 (1980) 93±98.
[36] D.D. Perrin and W.L.F. Armarego, Puri®cation of
Laboratory Chemicals, 3rd ed., Pergamon Press,
London, 1988.
[7] T. Fujiwara, S.W. Hunter, S.N. Cho, G.O. Aspi-
nall, and P.J. Brennan, Infect. Immun., 43 (1984)
245±252.
[8] S.N. Cho, T. Fujiwara, S.W. Hunter, R.H. Gelber,
and P.J. Brennan, J. Infect. Dis., 150 (1984) 311±322.
[9] J. Gigg, R. Gigg, S. Payne, and R. Contant, Chem.
Phys. Lipids, 35 (1985) 299±307.
[10] J. Gigg, R. Gigg, S. Payne, and R. Contant, Car-
bohydr. Res., 141 (1985) 91±97.
[11] T. Fujiwara, S. Izumi, and P.J. Brennan, Agric.
Biol. Chem., 49 (1985) 2301±2308.
[12] T. Fujiwara, S.W. Hunter, and P.J. Brennan, Car-
bohydr. Res., 148 (1986) 287±298.
[13] T. Fujiwara, G.O. Aspinall, S.W. Hunter, and P.J.
Brennan, Carbohydr. Res., 163 (1987) 41±52.
[14] T. Fujiwara and S. Izumi, Agric. Biol. Chem., 51
(1987) 2539±2547.