Efficient Synthesis of 3,6-Dideoxy-β-D-arabino-hexopyranosyl-Terminated LacdiNac Glycan Chains of the Trichinella spiralis Parasite

Article abstract of DOI:10.1021/jo991812k

The synthesis of a linear trisaccharide epitope of the Trichinella spiralis N-linked glycan, in a form amenable to glycoconjugate formation, is reported. The trisaccharide contains the synthetically challenging LacdiNAc [β-GalpNAc(1→4)-β-GlcpNAc] element,

Full text of DOI:10.1021/jo991812k

3064
J . Org. Chem. 2000, 65, 3064-3073
Efficien t Syn th esis of 3,6-Did eoxy-â-D-a r a bin o-h exop yr a n osyl-
Ter m in a ted La cd iNa c Glyca n Ch a in s of th e Tr ich in ella spir a lis
P a r a site
Mark Nitz and David R. Bundle*
Department of Chemistry, The University of Alberta, Edmonton, Alberta T6G 2G2, Canada
Received November 23, 1999
The synthesis of a linear trisaccharide epitope of the Trichinella spiralis N-linked glycan, in a
form amenable to glycoconjugate formation, is reported. The trisaccharide contains the synthetically
challenging LacdiNAc [â-GalpNAc(1f4)-â-GlcpNAc] element, as well as a terminal 3,6-dideoxy-
â-D-arabino-hexopyranose (tyvelose) residue. An orthogonal protection strategy is described, which
permits the protection and manipulation of three amino groups present in the disaccharide
â-GalNAc(1f4)-â-GlcNAc and the tether used to prepare neoglycoconjugates. The â-linked
dideoxyhexose was generated in excellent yield by the introduction of the dideoxyhexose unit as a
â-D-ribo-hexopyranoside (paratose) followed by an oxidation-reduction sequence to generate the
â-D-arabino configuration in high diastereomeric excess. The required dideoxyhexose donor was
synthesized in a series of high-yielding steps from glucose utilizing the p-methoxyphenyl glycoside.
In tr od u ction
Trichinella spiralis is a parasitic nematode that can
establish itself in the intestinal epithelia of carnivorous
animals. During invasion, T. spiralis secretes an array
of glycoproteins,1 the glycan chains of which have been
identified as large tri- and tetra-antennary structures,
terminating in a rare 3,6-dideoxy-â-D-arabino-hexopyran-
osyl (â-tyvelose or â-Tyv) linkage to a Lewis-x-like
trisaccharide.2,3 Immunochemical evidence using mono-
clonal antibodies established that not all of the glycan
chains are capped by the tetrasaccharide â-D-Tyvp(1f3)-
â-D-GalpNAc(1f4)[R-L-Fucp(1f3)]-â-D-GlcpNAc; a non-
fucosylated glycan tyvelose capped structure may also be
present (Figure 1).4-6 These highly unique glycan chains
are thought to play an important role in pathogenesis.
One line of evidence that points toward such a conclusion
is the in vivo protection afforded by certain monoclonal
antibodies that recognize the dideoxyhexose capped gly-
cans.7,8 Recognition of the glycan epitope by C-type lectins
may also play a role in mediating parasite adherence as
an initial step in pathogenesis. To investigate potential
roles for the surface glycans of this parasite in the
pathogenesis of T. spiralis, chemically defined neoglyco-
conjugates that can be used to locate glycan receptors in
tissue or cells are required. For this purpose, epitopes
labeled with fluorescent reporter groups are required.
F igu r e 1. T. spiralis capping tetrasaccharide. Dashed line
indicates absence of fucose residue in linear trisaccharide.
We report here the synthesis of a linear nonfucosylated
epitope with an ω-amino tether (33) to facilitate synthesis
of the corresponding fluorescein conjugate (1), as well as
the corresponding simple methyl glycoside (2) (Figure 1).
The latter molecule was also required to define the fine
specificity of one set of protective monoclonal antibodies
that appear to recognize the linear as opposed to the
fucose-branched epitope.4 The approach employs an
orthogonal protection strategy that permits the protection
and manipulation of three amino groups, present in the
tether, and the two amino sugars. It also accommodates
the introduction, manipulation, and deprotection of the
acid-labile 3,6-dideoxy-â-D-arabino-hexopyranosyl resi-
due, which, if not hydrolyzed, is readily anomerized.
(1) Appleton, J . A.; Usack, L. Mol. Biochem. Parasitol. 1993, 58, 53-
62.
Resu lts a n d Discu ssion
(2) Reason, A. J .; Ellis, L. A.; Appleton, J . A.; Wisnewski, N.; Grieve,
R. B.; McNeil, M.; Wassom, D. L.; Morris, H. R.; Dell, A. Glycobiology
1994, 4, 593-603.
Syn th etic Str a tegy a n d P r ep a r a tion of Mon osa c-
ch a r id e Bu ild in g Block s (F igu r e 2). The target oli-
gosaccharides to be synthesized were 6-aminohexyl gly-
coside (33) and methyl glycoside (2). The strategy chosen
relies on the stepwise addition of monosaccharides from
the reducing terminus of the molecule, with the glycosidic
linkage to the most valuable sugar, tyvelose, being
established last. Elaboration of the oligosaccharides as
the 6-aminohexyl glycoside facilitates later attachment
to fluorescent reporter groups that will be used to study
(3) Wisnewski, N.; McNeil, M.; Grieve, R. B.; Wassom, D. L. Mol.
Biochem. Parasitol. 1993, 1, 25-35.
(4) Ellis, L. A.; McVay, C. S.; Probert, M. A.; Zhang, J .; Bundle, D.
R. Glycobiology 1997, 7, 388-390.
(5) Zhang, J .; Otter, A.; Bundle, D. R. Bioorg. Med. Chem. 1996, 4,
1989-2001.
(6) Probert, M. A.; Zhang, J .; Bundle, D. R. Carbohydr. Res. 1996,
296, 149-170.
(7) Appleton, J . A.; Schain, L. R.; McGregor, D. D. Immunology 1988,
65, 487-492.
(8) Denkers, E. Y.; Hayes, C. E.; Wassom, D. L. Exp. Parasitol. 1991,
72, 403-410.
10.1021/jo991812k CCC: $19.00 © 2000 American Chemical Society
Published on Web 04/20/2000

LacdiNac Glycan Chains of Trichinella spiralis
J . Org. Chem., Vol. 65, No. 10, 2000 3065
remains the oxidation and reduction of the C2 alcohol to
convert the 1,2-trans (2-D-glycero) to the 1,2-cis (2-L-
glycero) configuration.19,20 This approach was applied
here to introduce the terminal tyveloside via its 3,6-
dideoxy-D-ribo-hexopyranose (paratose) epimer.
Early synthetic investigations showed a facile elimina-
tion reaction upon oxidation of the paratose C2 position
in the presence of a benzoyl group at the 4 position.
Therefore, the thioglycoside donor was synthesized with
benzyl protection at C4 and a participating pivaloyl ester
at position C2 to ensure â selectivity and to avoid
complications of ortho ester formation previously encoun-
tered for other paratose donors.21
F igu r e 2. Monosaccharide building blocks.
the trisaccharide’s biological significance.9 The methyl
glycoside functions as the most convenient form for
crystallography and epitope mapping.10 The glucosamine
synthons 17 and 1811 employed the persistent phthal-
imido derivative of the amine, ensuring solubility of the
compound and stability of this group to all subsequent
reaction conditions. The 6-chlorohexyl agylcone could
easily be transformed to the azide after all steps employ-
ing reducing conditions had been performed. The galac-
tosamine derivative 19 was chosen as an efficient glycosyl
donor for the formation of LacdiNac glycoside. It could
be synthesized in high yield from the comparatively
expensive galactosamine starting material. Furthermore,
this choice of protecting groups provides three levels of
orthogonal amine protection (as in 26), which is required
to minimize solubility and chromatographic difficulties
often encountered in small compounds with multiple
acetamido groups. This also provides a free amine after
the final deprotection steps to allow for facile neoglycon-
jugate formation.
Syn th esis of Mon osa cch a r id e Syn th on s. Beginning
with the easily accessible p-methoxyphenyl tetra-O-
2,3,4,6-acetyl-â-D-glucopyranoside,12 deacetylation and
conversion to the benzylidene acetal by treatment with
benzyaldhyde dimethyl acetal gave the highly crystalline
compound 3. According to a series of high-yielding steps
introduced by Bundle,22 the 3-deoxy-ribo-hexopyranoside
(7) was synthesized. The crystalline bis-chlorosulfate
ester (4) was cleanly prepared by treatment of the diol
(3) with sulfuryl chloride. Reaction of the dichlorosulfate
ester (4) with tetrabutylammonium bromide followed by
hydrolysis with an aqueous solution of potassium carbon-
ate and potassium iodide gave the 3-bromo-3-deoxy-allo-
pyranoside (5) in high yield. The stereochemistry at C3
was confirmed by proton NMR analysis of the coupling
3
3
constants J 2,3 ≈ J 3,4 ≈ 3.4 Hz, indicative of an axial
orientation of the bromide. This compound was protected
as the TDBMS ether (6) and hydrogenated over pal-
ladium to give the desired 3-deoxy-ribo-hexopyranoside
(7). The 6-deoxy function was introduced in two steps via
treatment of the benzylidene acetal with NBS, to the give
the 6-bromo derivative (8), and reduction over palladium
on carbon. The hydrogenolysis was accomplished in the
presence of potassium carbonate in a solution of ethanol,
resulting in concurrent debenzoylation to give the para-
tose derivative (9) in high yield. A benzyl ether was then
introduced at C4 under standard conditions (10); removal
of the silyl ether with tetrabutylammonium fluoride (11)
and protection as the pivolyl ester gave compound 12.
Finally, the p-methoxyphenyl glycoside could be readily
converted to the thioglycoside12 by treatment with thiophe-
nol and boron trifluoride diethyl etherate to give an
anomeric mixture of the desired glycosyl donor (13) in
90% yield (Figure 3).
The paratose glycosyl donor 13 was available through
a series of high-yielding steps from the easily synthesized
p-methoxyphenyl 2,3,4,6-tetraacetyl-â-D-glucopyrano-
side.12 The p-methoxyphenyl protecting group was an
ideal persistent protecting group for this synthesis, being
readily available, stable to many conditions, and easily
converted to the thiophenyl glycoside necessary for
glycosylation.
Synthesis of the 1,2-cis â linkage remains one of the
most challenging tasks in oligosaccharide chemistry. New
methodologies have been developed based on specialized
glycosyl donors,13,14 heterogeneous catalysis,15 and el-
egant intramolecular aglycone delivery.16-18 However,
many of these methods either are not applicable to highly
reactive 3,6-dideoxyhexose sugars or give anomeric mix-
tures.5,6 Preliminary and quite extensive attempts to
synthesize the target compounds employing intramolecu-
lar aglycon delivery with tethers derived from p-meth-
oxybenzyl and silyl ethers and activated donors in the
form of tethered glycosyl fluorides, thioglycosides, or
sulfoxides failed to give acceptable yields. Nontethered
3-deoxyhexose donors locked in the 4C1 conformation and
bearing nonparticipating groups at C2 were also tried
without success. The most general and robust method
The methyl glycoside (18) was prepared according to
literature procedures,11 and the 6-chlorohexyl glycoside
(17) was prepared analogously (Figure 4). The terminal
chloride proved to be stable to the reductive opening of
the benzylidiene acetal and the basic Zemplen deacety-
lation conditions, providing a simple way to introduce a
terminal azide later in the synthesis.
(9) Neurohr, K. J .; Mantsch, H. M.; Young, N. M.; Bundle, D. R.
Biochemistry 1982, 21, 498-503.
Assem bly of Oligosa cch a r id es (F igu r e 5). Galac-
tosaminyl donor 19 was synthesized from the literature
derivative 1,3,4,6-O-tetraacetyl-2-deoxy-2-(2,2,2-trichlo-
roethoxycarbonylamino)-â-D-galactopyranose by treat-
(10) Bundle, D. R.; Baumann, H.; Brisson, J . R.; Gagne, S. M.;
Zdanov, A.; Cygler, M. Biochemistry 1994, 33, 5183-5192.
(11) Alais, J .; David, S. Carbohydr. Res. 1990, 201, 69-77.
(12) Zhang, Z.; Magnusson, G. Carbohydr. Res. 1996, 295, 41-55.
(13) Lichtenthaler, F. W.; Schneider-Adams, T. J . Org. Chem. 1994,
59, 6728-6734.
(14) Crich, D.; Sun, S. J . Org. Chem. 1997, 62, 1198-1199.
(15) Garreg, P. J .; Ossowski, P. Acta Chem. Scand. 1983, B37, 249-
250.
(16) Barresi, F.; Hindsgaul, O. J . Am. Chem. Soc. 1991, 113, 9376-
9377.
(17) Stork, G.; Kim, G. J . Am. Chem. Soc. 1992, 114, 1087-1088.
(18) Ito, Y.; Ogawa., T. Angew. Chem., Int. Ed. Engl. 1994, 33, 1765-
1767.
(19) Boren, H. B.; Ekborg, G.; Eklind, K.; Garegg, P. J .; Pilotti, A.;
Swahn, C-G. Acta Chem. Scand. 1973, 27, 2639-2644.
(20) Auge, C.; Warren, C. D.; J ealoz, R. W.; Kiso, M.; Andersen, L.
Carbohydr. Res. 1980, 82, 85-95.
(21) Zheng, C. M.Sc. Dissertation, University of Alberta, Edmonton,
Alberta, Canada, 1998.
(22) Bundle, D. R. J . Chem. Soc., Perkin Trans. 1 1979, 2751-2755.

3066 J . Org. Chem., Vol. 65, No. 10, 2000
Nitz and Bundle
This combination of donor and acceptor proved to give
higher yields than other combinations used to synthesize
LacdiNAc.23,27 Cleavage of the trichloroethylcarbamate
was most efficient and reproducible using cadmium metal
in a 1:1 solution of DMF and acetic acid.28 The free amine
was acetylated in methanol to give compounds 22 and
23. The benzylidene acetal was installed with benzalde-
hyde dimethyl acetal and toluenesulfonic acid after
Zemplen deacetylation to give the target acceptors 24 and
25 in good yield. The terminal chloride was then easily
displaced with sodium azide to give the orthogonally
protected amine-terminated linker 26.
Activation of paratose donor 13 with N-iodosuccin-
imide24,25 and a catalytic amount of silver triflate26 in the
presence of the alcohol 24 or 26 gave the desired
trisaccharide 27 or 28 in greater than 75% yield. Unfor-
tunately, a 20:1 â:R ratio that could not be separated by
standard silica gel chromatography was obtained in the
reaction. This mixture was separated in subsequent steps
of the synthesis.
The pivaloyl and phthalimido protecting groups were
removed in the next steps via treatment with ethylene-
diamine29 at 110 °C for 16 h, but these conditions failed
to completely remove the pivaloyl ester. The free amine
was acetylated using acetic anhydride in methanol, and
the remaining pivaloyl ester was removed with a solution
of sodium methoxide in methanol to give the glycosides
29 and 30.
The oxidation and reduction19,20 of the paratose glyco-
sides 29 and 30 was accomplished in two steps, per-
formed sequentially in a one-pot reaction. Treatment for
18 h with a 2:1 mixture of dimethyl sulfoxide and acetic
anhydride, followed by removal of the volatile compo-
nents under high vacuum, gave the corresponding ulo-
sides as yellow solids. Reduction with excess L-selectride
gave the tyvelose-terminated trisaccharides 31 and 32.
Quenching the reaction of the 6-azidohexyl glycoside (30)
with ethylenediamine avoided reduction of the azide and
gave 32 in 75% yield. Previous model studies on the
oxidation and reduction of methyl 4-O-benzoyl-3,6-dideoxy-
â-D-ribo-hexopyranoside indicated that the sterically
bulky L-selectride gave superior selectivity upon reduc-
tion than did sodium borohydride.
F igu r e 3. (i) (a) MeONa/MeOH, (b) PhCH(OMe)2, pTSA, CH3-
CN, 86%; (ii) SO2Cl2, pyridine, CH2Cl2, 91%; (iii) (a) Et4NBr,
CH2Cl2, (b) KI, KHCO3, MeOH/H2O, 96%; (iv) TBDMSCl,
imidazole, DMF, 91%; (v) H2, Pd/C, EtOAc/EtOH, 87%; (vi)
NBS, BaCO3, CCl4, reflux, 93%; (vii) H2, Pd/C, KHCO3, EtOH,
93%; (viii) BnBr, NaH, DMF, 88%; (ix) Bu4NF, THF, 92%; (x)
PivCl, pyr, 91%; (xi) PhSH, BF3‚OEt2, CH2Cl2, 2:1 R:â, 90%.
The inversion of stereochemistry was confirmed by
3
NMR. The J 1,2 value of <1 Hz was indicative of a 1,2-
1
cis-mannosyl linkage,30 while the heteronuclear J C1,H1
constant of 158 Hz unambiguously established the â
configuration.31 No products with the ribo configuration
were observed in the NMR spectrum of the crude product,
indicating that the selectivity of the reduction was better
than 95%.
F igu r e 4. (i) Cl(CH2)6OH, lutidine, AgOTf, CH2Cl2, 90%; (ii)
(a) NaOMe/MeOH, (b) PhCH(OMe)2, CH3CN, pTSA, 86%; (iii)
BnBr, NaH, DMF, 89%; (iv) NaCNBH3, HCl, THF, 92%.
Final deprotection of 31 and 32 gave the desired
trisaccharides 2 and 33. The methyl glycoside was
hydrogenated over palladium hydroxide and could be
crystallized from methanol/ethanol mixtures as fine
needles in 93% yield. The 6-azidohexyl trisaccharide was
ment with thiophenol and BF3‚OEt2.23 This proved to be
an excellent glycosyl donor for the formation of glycosides
20 and 21 in greater than 87% yield using N-iodosuc-
cinimide24,25 and a catalytic portion of silver triflate.26
(27) Hokke, C. H.; van der Ven, J . G. M.; Kamerling, J . P.;
Vliegenthart, J . F. G. Glycoconjugate J . 1993, 10, 82-90.
(28) Hancock, G.; Galpin, I. J .; Morgan, B. A. Tetrahedron Lett. 1982,
23, 249-252.
(23) Ellervik, U.; Magnusson, G. Carbohydr. Res. 1996, 280, 251-
260.
(24) Kondradsson, P.; Mootoo, D. R.; Mcdevitt, R. E.; Frasier-Reid,
B. J . Chem. Soc., Chem. Commun. 1990, 270-272.
(25) van Leeuwen, S. H.; Zuurmond, H.; van Boom, J . H. J .
Carbohydr. Chem. 1990, 9, 783-796.
(26) Lowary, T.; Eichler, E.; Bundle, D. R. J . Org. Chem. 1995, 60,
7316-7327.
(29) Kanie, O.; Crawley, S. C.; Palcic, M. M.; Hindsgaul, O. Carbo-
hydr. Res. 1993, 243, 139-164.
(30) Otter, A.; Hindsgaul, O.; Bundle, D. R. Carbohydr. Res. 1995,
275, 381-389.
(31) Bock, K.; Pedersen, C. J . J . Chem. Soc., Perkin Trans. 2 1974,
293-297.

LacdiNac Glycan Chains of Trichinella spiralis
J . Org. Chem., Vol. 65, No. 10, 2000 3067
F igu r e 5. (i) PhSH, BF3‚OEt2, 74%; (ii) 17, NIS, AgOTf, CH2Cl2, 87-93%; (iii) (a) Cd, 1:1 AcOH/DMF, (b) MeOH, Ac2O, 79-88%;
(iv) (a) MeONa/MeOH, (b) PhCH(OMe)2, pTSA, CH3CN, 79-85%; (v) NaN3, DMSO, 96%; (vi) 13, NIS, AgOTf, CH2Cl2, 81-85%;
(vii) (a) NH2CH2CH2NH2, BuOH, (b) Ac2O, MeOH, (c) MeONa/MeOH, 85-88%; (viii) (a) DMSO, Ac2O, (b) L-selectride, THF, 81%;
(ix) Pd(OH)2/C, EtOH, 88%; (x) NH2CH2CH2NH2, Li, 82%; (xi) 1:1 DMF/H2O, NaHCO3, FluorNCS, 75%.
deprotected under dissolving metal conditions32 using
formed on Silica Gel F254 (Merck) precoated glass plates and
visualized with 5% H2SO4 in ethanol. Flash chromatography
ethylenediamine as the solvent because of the low
solubility of the LacdiNAc structure in THF/ammonia
was performed on Silica Gel 60 (40-63 µm, Merck no. 9385).
AG 50W H+ resin was purchased from Bio-Rad Laboratories.
mixtures. Final purification by HPLC and lyophization
p-Meth oxyben zyl 4,6-O-ben zylid en e-â-D-glu cop yr a n o-
gave 33 as a white powder in 82% yield. The 6-amino-
sid e (3). p-Methoxyphenyl 2,3,4,6-O-â-D-tetraacetylglucopy-
hexyl tether was then simply derivatized as its fluores-
ceine conjugate by stirring with fluoresceine isothiocynate
in a DMF/water solution; final purification gave 1 in 75%
ranoside12 (8.0 g, 17 mmol) was dissolved in dry methanol (50
mL), and a catalytic amount of sodium metal (∼10 mg) was
added to the reaction mixture. After the solution was stirred
for 2 h, TLC in 1:1 EtOAc/hexane showed complete conversion
to baseline material. The solution was then neutralized with
AG 50W H+ resin and filtered. Concentration to dryness gave
a white solid to which dry acetonitrile (100 mL) was added,
followed by benzaldehyde dimethyl acetal (4.0 mL, 26 mmol).
The mixture was then heated to reflux, and p-toluenesulfonic
acid (200 mg) was added. Once a homogeneous solution was
obtained, heating was terminated, and the solution was
neutralized with triethylamine. The reaction mixture was then
concentrated to dryness to give a white solid. Recrystallization
from methanol gave white needles (5.46 g, 86%). Mp: 213-
214 °C. [R]D: -35.0 (c 1.0, DMF). 1H NMR (300 MHz, CD3-
OD): δ 7.48-7.51 (m, 2H, Ar), 7.32-7.35 (m, 3H, Ar), 6.99-
7.04 (m, 2H, Ar), 6.82-6.86 (m, 2H, Ar), 5.59 (s, 1H, PhCHO2),
4.91 (d, 1H, J 1,2 ) 7.7 Hz, H1), 4.20 (dd, 1H, J gem ) 10.1 Hz,
J 5,6eq ) 3.8 Hz, H6eq), 3.78 (dd, 1H, J 5,6ax ) 8.25 Hz, H6ax),
3.74 (s, 3H, OCH3), 3.72 (dd, 1H, J 2,3 ≈ J 3,4 ) 9.0 Hz, H3),
3.49-3.57 (m, 3H, H2, H5, H4). Anal. Calcd for C20H22O7: C,
64.16; H, 5.92. Found: C, 64.14; H, 5.79.
yield.
Su m m a r y
Through the use of an oxidation-reduction protocol at
C2 of 3,6-dideoxy-â-D-ribo-hexopyranose, the difficult to
synthesize 3,6-dideoxy-â-D-arabino-hexopyranose linkage
has been introduced at O3 of the disaccharide â-D-
GalpNAc(1f4)-â-D-GlcpNAc. This approach provides the
methyl glycoside (2) and linker-derivatized trisaccharide
(33) for the preparation of the fluorescein glycoconjugate
(1).
Exp er im en ta l Section
Melting points were determined on glass plates using a
Fisher-J ohns melting point apparatus and are uncorrected.
Optical rotations were measured using a polarimeter at 22 (
1
2 °C. The H NMR spectra were recorded at 300 and 600 MHz
p -Met h oxyb en zyl 4,6-O-b en zylid en e-2,3-d i-O-ch lor o-
su lfa te-â-D-glu cop yr a n osid e (4). A solution of 3 (4.7 g, 12.7
mmol) in dry dichloromethane (50 mL) and dry pyridine (25
mL) was cooled to -78 °C. Sulfuryl chloride (2.25 mL, 28.0
mmol) was then added dropwise with stirring over 15 min,
and the solution was then allowed to warm to room temper-
ature over 2 h. The reaction mixture was diluted with
dichloromethane, washed with 10% H2SO4 and then water,
dried over Na2SO4, and concentrated, and compound 4 was
crystallized from EtOAc/hexane (6.56 g, 91%). Mp: 148 °C,
on a Varian Inova spectrometer and at 500 MHz on a Varian
Unity spectrometer. All data were obtained with temperature
control to 25 °C. Chemical shifts are referenced to residual
CHCl3 at 7.24 ppm for CDCl3 solutions, to residual CHD2OD
at 3.30 ppm for CD3OD solutions, and to 0.1% external acetone
at 2.225 ppm for D2O solutions. NMR assignments were made
by two-dimensional homonuclear and heteronuclear shift-
correlation experiments. Thin-layer chromatography was per-
1
dec. [R]D: -63.2 (c 1.0, CHCl3). H NMR (300 MHz, CD2Cl2):
(32) Lu, P.-P.; Hindsgaul, O.; Li, H.; Palcic, M. M. Carbohydr. Res.
1997, 303, 283-291.
δ 7.47-7.50 (m, 3H, Ar), 7.36-7.40 (m, 2H, Ar), 7.02-7.05 (m,

3068 J . Org. Chem., Vol. 65, No. 10, 2000
Nitz and Bundle
2H, Ar), 6.85-6.88 (m, 2H, Ar), 5.66 (s, 1H, PhCHO2), 5.14-
5.29 (m, 3H, H1, H2, H3), 4.48 (dd, 1H, J gem ) 10.6 Hz, J 5,6eq
) 4.9 Hz, H6eq), 4.04 (dd, 1H, J 3,4 ≈ J 4,5 ) 9.4 Hz, H4), 3.90
(dd, 1H, J 5,6ax ) 10.0 Hz, H6ax), 3.77 (s, 3H, OCH3), 3.68 (ddd,
1H, H5). Anal. Calcd for C20H26Cl2O11S2: C, 42.04; H, 3.53;
Cl, 12.41. Found: C, 41.88; H, 3.28; Cl, 12.69.
(50 mL) for 30 min. During this time, the solution changed
from colorless to deep orange and then to pale yellow. The
reaction mixture was filtered, diluted with dichloromethane,
washed with 5% sodium thiosulfate and then water, and dried
over sodium sulfate. The solution was then concentrated to a
syrup and chromatographed in 4:1 EtOAc/hexane to give the
6-bromo derivative (8), which crystallized upon standing (2.72
g, 93%). Mp: 108-110 °C. [R]D: -40.7 (c 0.5, CHCl3). 1H NMR
(300 MHz, CDCl3): δ 7.99-8.02 (m, 2H, Ph), 7.55-7.61 (m,
1H, Ar), 7.42-7.47 (m, 2H, Ar), 7.04-7.08 (m, 2H, PhOMe),
6.81-6.85 (m, 2H, PhOMe), 4.98 (ddd, 1H, J 3ax,4 ) 11.1 Hz,
J 3eq,4 ) 4.8 Hz, J 4,5 ) 9.4 Hz, H4), 4.80 (d, 1H, J 1,2 ) 7.3 Hz,
H1), 3.86-3.95 (m, 2H, H2, H5), 3.57 (dd, 1H, J 5,6 ) 2.5 Hz,
p-Meth oxyben zyl 4,6-O-ben zylid en e-3-br om o-3-d eoxy-
â-D-a llo-p yr a n osid e (5). To a solution of 4 (10.9 g, 19.1 mmol)
in dry dichloromethane (75 mL) was added tetrabutylammo-
nium bromide (10.9 g, 42.4 mmol), and the reaction mixture
was stirred for 1 h at room temperature. The solution was
diluted with dichloromethane and washed with saturated
sodium bicarbonate; the organic solution was dried over
sodium sulfate and concentrated to yellow syrup. The syrup
was dissolved in methanol (200 mL); water (5 mL), KHCO3
(20 g), and KI (100 mg) were added; and stirring was continued
for 15 min. The solution was filtered and concentrated to a
syrup. Chromatography in 2:1 hexane/EtOAc gave a colorless
oil (8.01 g, 96%). [R]D: -18.0 (c 1.0, CHCl3). 1H NMR (300 MHz,
CD2Cl2): δ 7.49-7.52 (m, 3H, Ar), 7.38-7.41 (m, 2H, Ar),
7.38-6.99 (m, 2H, Ar), 6.88-6.83 (m, 2H, Ar), 5.65 (s, 1H,
J gem ) 11.1 Hz, H6a), 3.76 (s, 3H, OCH3), 3.41 (dd, 1H, J 5,6
)
8.2 Hz, H6b), 2.56 (ddd, 1H, J gem ) 12.5 Hz, J 2,3eq ) 5.1 Hz,
H3eq), 1.79 (ddd, 1H, J 2,3 ) 12.5 Hz, H3ax), 0.86 (s, 9H, (CH3)3-
CSi), 0.13 (s, 3H, SiCH3), 0.12 (s, 3H, SiCH3). Anal. Calcd for
C26H35BrO6Si: C, 56.62; H, 6.40. Found: C, 56.40; H, 6.30.
p -Met h oxyb en zyl 2-O-ter t-b u t yld im et h ylsilyl-3,6-d i-
d eoxy-r ibo-h exop yr a n osid e (9). To a solution of 6-bromo
derivative 8 (1.0 g, 1.81 mmol) in ethanol were added KHCO3
(500 mg) and then 10% Pd/carbon (100 mg). The mixture was
hydrogenated with stirring for 48 h at 1 atm. The mixture was
filtered through Celite, concentrated to a syrup, taken up in
EtOAc, and washed twice with water. The organic phase was
dried over sodium sulfate and concentrated to a colorless
syrup, which was chromatographed in 2:1 EtOAc/hexane to
give a colorless oil (0.62 g, 93%). [R]D: -51.9 (c 1.6, CHCl3).
1H NMR (300 MHz, CDCl3): δ 6.92-6.96 (m, 2H, Ar), 6.78-
6.82 (m, 2H, Ar), 4.77 (d, 1H, J 1,2 ) 6.7 Hz, H1), 3.78 (ddd,
1H, J 2,3ax ) 10.3 Hz, J 2,3eq ) 5.0 Hz, H2), 3.75 (s, 3H, CH3O),
3.40-3.48 (m, 2H, H4, H5), 2.32 (ddd, 1H, J gem ) 12.6 Hz, J 3,4
) 4.6 Hz, H3eq), 1.63 (ddd, 1H, J 3ax,4 ) 10.3 Hz, H3ax), 1.30 (d,
3H, J 5,6 ) 5.9 Hz, H6), 0.88 (s, 9H, (CH3)3CSi), 0.12 (s, 3H,
SiCH3), 0.09 (s, 3H, SiCH3). Anal. Calcd for C19H32O5Si: C,
61.92; H, 8.75. Found: C, 61.61; H, 8.69. HR electrospray
m/z: calcd for C19H32O5SiNa, 391.191673; found, 391.191592.
p-Meth oxyben zyl 4-O-ben zyl-2-O-ter t-bu tyld im eth yl-
silyl-3,6-d id eoxy-â-D-r ibo-h exop yr a n osid e (10). To a solu-
tion of 9 (600 mg, 1.63 mmol) in dry DMF (10 mL) at room
temperature were added benzyl bromide (420 µL, 3.53 mmol)
and then sodium hydride (65 mg, 2.7 mmol). After 5 h, TLC
indicated the absence of starting material. The solution was
diluted with dichloromethane and washed with water, and the
organic layer was dried over sodium sulfate and concentrated.
The resulting syrup was chromatographed in 9:1 hexane/Et2O
to give a white solid (658 mg, 88%), which was recrystallized
from EtOAc/hexane. Mp: 59-60 °C. [R]D: -25.0 (c 1.0, CHCl3).
1H NMR (300 MHz, CDCl3): δ 7.29-7.34 (m, 5H, Ph), 6.93-
6.96 (m, 2H, Ar), 6.78-6.81 (m, 2H, Ar), 4.70 (d, 1H, J 1,2 ) 7.4
Hz, H1), 4.64 (d, 1H, J gem ) 11.5 Hz, PhCH2), 4.48 (d, 1H,
PhCH2), 3.75 (s, 3H, CH3O), 3.69 (ddd, 1H, J 2,3eq ) 5.2 Hz,
J 2,3ax ) 11.4 Hz, H2), 3.50 (dq, 1H, J 4,5 ) 9.0 Hz, J 5,6 ) 6.1 Hz,
H5), 3.17 (ddd, 1H, J 3eq,4 ) 4.5 Hz, J 3ax,4 ) 11.2 Hz, H4), 2.40
(ddd, 1H, J gem ) 12.6 Hz, H3eq), 1.56 (ddd, 1H, H3ax), 1.31 (d,
3H, H6), 0.87 (s, 9H,(CH3)3CSi), 0.12 (s, 3H, SiCH3), 0.08 (s,
3H, SiCH3). Anal. Calcd for C26H38O5Si: C, 68.08; H, 8.35.
Found: C, 68.00; H, 8.58.
PhCHO2), 5.22 (d, 1H, J 1,2 ) 7.6 Hz, H1), 4.89 (dd, 1H, J 2,3
≈
J 3,4 ) 3.4 Hz, H3), 4.39 (dd, 1H, J gem ) 10.4 Hz, J 5,6eq ) 5.1
Hz, H6eq), 4.15 (ddd, 1H, J 4,5 ≈ J 5,6ax ) 9.7 Hz, H5), 3.76-3.88
(m, 3H, H2, H4, H6ax), 3.71 (s, 3H, OCH3). Anal. Calcd for
C
20H21O6Br: C, 54.93; H, 4.84. Found: C, 54.39; H, 4.83. HR
electrospray m/z: calcd for C20H21O6BrNa, 459.041919 (M +
Na)+; found, 459.041886.
p-Meth oxyben zyl 4,6-O-ben zylid en e-3-br om o-2-O-ter t-
bu tyld im eth ylsilyl-3-d eoxy-â-D- a llo-p yr a n osid e (6). To
a solution of 5 (2.6 g, 5.6 mmol) in dry DMF (20 mL) were
added imidazole (600 mg, 8.81 mmol) and tert-butylchlorodi-
methylsilane (1.2 g, 8.0 mmol). The solution was heated to 60
°C and stirred for 3 h. After cooling, the reaction mixture was
diluted with dichloromethane (150 mL) and washed with
water, and the organic phase was dried over sodium sulfate
and concentrated to a syrup. Column chromatography in 10:1
hexane/Et2O gave a colorless syrup (3.2 g, 91%). [R]D: -41.8
1
(c 1.1, CHCl3). H NMR (300 MHz, CDCl3): δ 7.48-7.50 (m,
2H, Ar), 7.36-7.34 (m, 3H, Ar), 6.94-6.98 (m, 2H, Ar), 6.80-
6.83 (m, 2H, Ar), 5.59 (s, 1H, PhCHO2), 5.23 (d, 1H, J 1,2 ) 7.2
Hz, H1), 4.67 (dd, 1H, J 2,3 ≈ J 3,4 ) 3.0 Hz, H3), 4.38 (dd, 1H,
J 5,6ax ) 9.6 Hz, J gem ) 10.3 Hz, H6ax), 4.20 (ddd, 1H, J 4,5 ) 9.0
Hz, J 5,6eq ) 5.2 Hz, H5), 3.85 (dd, 1H, H2), 3.81 (dd, 1H, H6eq),
3.71 (dd, 1H, H4), 3.70 (s, 3H, OMe), 0.90 (9H, s, (CH3)3CSi),
0.16 (s, 3H, CH3Si), 0.13 (s, 3H, CH3Si). Anal. Calcd for C26H35
-
BrO6Si: C, 56.62; H, 6.40. Found: C, 56.93; H, 6.50.
p-Meth oxyben zyl 4,6-O-ben zylid en e-2-O-ter t-bu tyld i-
m eth ylsilyl-3-deoxy-â-D-r ibo-h exopyr an oside (7). The allo-
pyranoside 6 (5.00 g, 10.5 mmol) was dissolved in a 1:1 mixture
of EtOAc and EtOH, and KHCO3 (3 g) and 10% Pd/carbon (500
mg) were added. The mixture was then stirred under 1 atm
of hydrogen for 4 days, filtered through Celite, and concen-
trated to dryness. The resulting white solid was taken up in
dichloromethane (200 mL) and washed with water, and the
organics were dried and concentrated. The resulting white
solid was recrystallized from EtOAc/hexane (4.32 g, 87%).
1
Mp: 143 °C. [R]D: -63.6 (c 0.55, CHCl3). H NMR (500 MHz,
CDCl3): δ 7.46-7.48 (m, 2H, Ph), 7.32-7.37 (m, 3H, Ph), 6.93-
6.98 (m, 2H, Ar), 6.81-6.83 (m, 2H, Ar), 5.60 (s, 1H, PhCHO2),
4.83 (d, 1H, J 1,2 ) 7.3 Hz, H1), 4.31 (dd, 1H, J gem ) 10.6 Hz,
p-Meth oxyben zyl 4-O-ben zyl-3,6-d id eoxy-r ibo-h exop y-
r a n osid e (11). The paratose derivative (10) (532 mg, 1.21
mmol) was dissolved in 1 M tetrabutylammonium fluoride in
THF (4 mL), and the resulting solution was stirred at room
temperature for 1 h. The solution was then concentrated and
subjected to chromatography in 1:1 EtOAc/hexane to give a
white solid (385 mg, 92%), which was recrystallized from
EtOAc/hexane. Mp: 132 °C. [R]D: -25.0 (c 1.0, CHCl3). 1H
NMR (300 MHz, CDCl3): δ 7.29-7.34 (m, 5H, Ar), 6.93-6.96
(m, 2H, Ar), 6.78-6.81 (m, 2H, Ar), 4.78 (d, 1H, J 1,2 ) 7.1 Hz,
H1), 4.64 (d, 1H, J gem ) 11.5 Hz, PhCH2), 4.50 (d, 1H, PhCH2),
3.76 (s, 3H, CH3O), 3.68 (m, 1H, H2), 3.61 (dq, 1H, J 4,5 ) 8.2
J 5,6eq ) 4.3 Hz, H6eq), 3.84 (ddd, 1H, J 2,3eq ) 5.2 Hz, J 2,3ax
11.5 Hz, H2), 3.75 (dd, 1H, J 5,6ax ) 10.6 Hz, H6ax), 3.75 (s, 3H,
CH3O), 3.62 (ddd, 1H, J 3ax,4 ) 11.7 Hz, J 3eq,4 ) 2.3 Hz, J 4,5
)
)
9.0 Hz, H4), 3.50 (ddd, 1H, H5), 2.43 (ddd, 1H, J gem ) 12.2
Hz, H3eq), 1.84 (ddd, 1H, H3ax), 0.87 (s, 9H, (CH3)3CSi), 0.12
(s, 3H, SiCH3), 0.09 (s, 3H, SiCH3). Anal. Calcd for C26H36O6-
Si: C, 66.07; H, 7.68. Found: C, 65.73; H, 7.72. HR electro-
spray m/z: calcd for
C26H36O6SiNa, 495.217887; found,
495.217680.
p-Meth oxyben zyl 4-O-ben zoyl-6-br om o-2-ter t-bu tyld i-
m eth ylsilyl-3,6-d id eoxy-â-D-r ibo-h exop yr a n osid e (8). The
3-deoxy-ribo-hexopyranoside (7) (2.5 g, 5.29 mmol) was re-
fluxed with N-bromosuccinimide (1.04 g, 5.84 mmol) and
barium carbonate (0.63 g, 3.1 mmol) in carbon tetrachloride
Hz, J 5,6 ) 6.2 Hz, H5), 3.25 (ddd, 1H, J 3ax,4 ) 10.6 Hz, J 3eq,4 )
4.3 Hz, H4), 2.56 (ddd, 1H, J gem ) 12.5 Hz, J 2,3eq ) Hz, H3eq),
1.60 (ddd, 1H, J 2,3ax ) 12.5 Hz, H3ax), 1.32 (d, 3H, H6). Anal.
Calcd for C20H24O5: C, 69.75; H, 7.02. Found: C, 69.55; H,
7.20.

LacdiNac Glycan Chains of Trichinella spiralis
J . Org. Chem., Vol. 65, No. 10, 2000 3069
p-Meth oxyben zyl 4-O-ben zyl-3,6-d id eoxy-2-O-p iva loyl-
r ibo-h exop yr a n osid e (12). Compound 11 (300 mg, 0.87
mmol) was dissolved in pyridine, 4-(dimethylamino)pyridine
(25 mg) and pivaloyl chloride (214 µL, 1.7 mmol) were added,
and the solution was stirred at room temperature overnight.
The reaction mixture was then concentrated, and the residue
was dissolved in dichloromethane, washed with water, dried
over sodium sulfate, concentrated, and chromatographed in
7:1 hexane/diethyl ether. The colorless syrup crystallized on
standing (338 mg, 91%) and was recrystallized from EtOAc/
mixture was stirred for 20 min, and then the reaction was
quenched by the addition of triethylamine. The reaction
mixture was concentrated and subjected to column chroma-
tography in 2:1 hexane/EtOAc to give an amorphous solid (798
mg, 86%). [R]D: +35.8 (c 1.0, CHCl3). 1H NMR (300 MHz,
CDCl3): δ 7.79-7.84 (m, 2H, Ar), 7.70-7.74 (m, 2H, Ar), 7.44-
7.46 (m, 2H, Ar), 7.32-7.38 (m, 3H, Ar), 5.55 (s, 1H, PhCHO2),
5.24 (d, 1H, J 1,2 ) 8.4 Hz, H1), 4.61 (dd, 1H, J 2,3 ) 10.5 Hz,
J 3,4 ) 8.5 Hz, H3), 4.37 (dd, 1H, J gem ) 10.5 Hz, J 5,6 ) 4.5 Hz,
H6eq), 4.22 (dd, 1H, H2), 3.78-3.85 (m, 2H, CH2O, H5), 3.67-
3.53 (m, 2H, H4, H6ax), 3.41 (ddd, 1H, J gem ) 9.7 Hz, J vic ) 7.2
Hz, J vic ) 5.9 Hz, CH2O), 3.29 (t, 2H, t, J ) 6.9 Hz, CH2Cl),
1.33-1.48 (m, 4H, OCH2CH2, CH2CH2Cl), 1.04-1.25 (m, 4H,
OCH2CH2CH2CH2); Anal. Calcd for C23H22ClNO7: C, 60.07; H,
4.82; N, 3.05. Found: C, 59.72; H, 4.67; N, 2.93. HR electro-
spray m/z: calcd for C27H30NO7NaCl, 538.16085; found,
538.161042.
6-Ch lor oh exyl 3-O-ben zyl-4,6-O-ben zylid en e-2-d eoxy-
2-p h th a lim id o-â-D-glu cop yr a n osid e (16). To a solution of
15 (2.5 g, 4.8 mmol) in dry dimethylformamide (20 mL) were
added benzyl bromide (700 µL, 5.8 mmol) and then sodium
hydride (150 mg, 6.2 mmol). The reaction mixture was stirred
overnight and then diluted with dichloromethane and washed
with water. The organic phase was dried over sodium sulfate,
concentrated, and subjected to column chromatography in 3:1
hexane/EtOAc to yield a white solid, which was recrystallized
from EtOAc/hexane (2.6 g, 89%). Mp: 111 °C. [R]D: +47.6 (c
1.0, CHCl3). 1H NMR (300 MHz, CDCl3): δ 7.6-7.9 (br m, 4H,
Ar), 7.49-7.52 (m, 2H, Ar), 7.35-7.40 (m, 3H, Ar), 6.84-7.00
(m, 5H, Ar), 5.60 (s, 1H, PhCHO2), 5.17 (d, 1H, J 1,2 ) 8.4 Hz,
H1), 4.78 (d, 1H, J gem ) 12.3 Hz, CH2Ph), 4.49 (d, 1H, CH2-
Ph), 4.40 (dd, 1H, J 2,3 ) 10.4 Hz, J 3,4 ) 8.6 Hz, H3), 4.38 (dd,
1H, J gem ) 10.4 Hz, J 5,6eq ) 3.9 Hz, H6eq), 4.16 (dd, 1H, H2),
1
hexane. Mp: 82-83 °C. [R]D: -16.5 (c 1.0, CHCl3). H NMR
(300 MHz, CDCl3): δ 7.25-7.36 (m, 5H, Ar), 6.91-6.96 (m,
2H, Ar), 6.76-6.82 (m, 2H, Ar), 4.82-4.91 (ABX, 2H, H1, H2),
4.62 (d, 1H, J gem ) 11.4 Hz, PhCH2), 4.45 (d, 1H, PhCH2), 3.74
(s, 3H, CH3O), 3.56 (dq, 1H, J 4,5 ) 8.9 Hz, J 5,6 ) 6.1 Hz, H5),
3.28 (ddd, 1H, J 3ax,4 ) 11.0 Hz, J 3eq,4 ) 4.6 Hz, H4), 2.56 (ddd,
1H, J gem ) 12.5 Hz, J 2,3eq ) 4.6 Hz, H3eq), 1.51 (ddd, 1H, J 2,3ax
) 11.0 Hz, H3ax), 1.34 (d, 3H, H6), 1.19 (s, 9H, C(CH3)3). Anal.
Calcd for C25H32O6: C, 70.07; H, 7.53. Found: C, 69.86; H,
7.66.
P h en yl 4-O-ben zyl-3,6-dideoxy-2-O-pivaloyl-r ibo-1-th io-
h exop yr a n osid e (13). To an ice cold solution of 12 (510 mg,
1.19 mmol) dissolved in dry dichloromethane were added
dropwise thiophenol (196 µL, 1.8 mmol) and then BF3‚OEt2
(200 µL, 1.43 mmol). The reaction mixture was stirred for 2 h
on an ice bath, and then the reaction was quenched with
triethylamine. The resulting solution was diluted with dichlo-
romethane and washed with saturated sodium bicarbonate
solution. The organic phase was dried over sodium sulfate and
concentrated to an oil, which was subjected to chromatography
in 7:1 hexane/EtOAc to give a colorless syrup (445 mg, 90%).
NMR revealed a 2:1 mixture of R and â anomers. Crystalliza-
tion from hexane/EtOAc gave the pure R isomer. The following
data are for the R anomer only. Mp: 131 °C. [R]D: +272.2 (c
1.00, CHCl3). 1H NMR (300 MHz, CDCl3): δ 7.20-7.43 (m,
10H, Ar), 5.64 (d, 1H, J 1,2 ) 5.1 Hz, H1), 4.97 (ddd, 1H, J 2,3eq
) 4.8 Hz, J 2,3ax ) 12.5 Hz, H2), 4.66 (d, 1H, J gem ) 11.5 Hz,
PhCH2), 4.48 (d, 1H, PhCH2), 4.21 (dq, 1H, J 4,5 ) 9.3 Hz, J 5,6
) 6.2 Hz, H5), 3.22 (ddd, 1H, J 3ax,4 ) 11.9 Hz, J 3eq,4 ) 4.5 Hz,
H4), 2.36 (ddd, 1H, J gem ) 11.9 Hz, H3eq), 1.83 (ddd, 1H, H3ax),
1.25 (d, 3H, H6), 1.22 (s, 9H, C(CH3)3). Anal. Calcd for
3.73-3.88 (m, 3H, H4, H6ax, CH2CH2O), 3.62 (ddd, 1H, J 4,5
≈
J 5,6ax ) 9.7 Hz, H5), 3.36 (dt, 1H, J gem ) 8.7 Hz, J vic ) 6.0 Hz,
CH2CH2O), 3.27 (t, 2H, J ) 6.9 Hz, CH2Cl), 1.29-1.47 (m, 4H,
OCH2CH2, CH2CH2Cl), 0.98-1.20 (m, 4H, OCH2CH2CH2CH2).
Anal. Calcd for C34H38NO7: C, 67.38; H, 5.99; N, 2.31. Found:
C, 67.20; H, 6.04; N, 2.28.
6-Ch lor oh exyl 3,6-d i-O-ben zyl-2-d eoxy-2-p h th a lim id o-
â-D-glu cop yr a n osid e (17). The benzylidene acetal 16 (700
mg, 1.15 mmol) was added to a round-bottom flask containing
3-Å molecular sieves, methyl orange (2 mg), and sodium
cyanoborohydride (360 mg, 5.73 mmol). The flask was purged
with argon, and dry THF (15 mL) was added. The mixture
was allowed to stir for 2 h, and then the flask was fitted with
a dropping funnel containing a saturated solution of HCl in
diethyl ether. This solution was added dropwise to the reaction
mixture until the pink color remained and no further gas
evolution was evident. The reaction mixture was stirred for
30 min, the reaction was quenched with triethylamine, and
the reaction mixture was filtered through Celite and concen-
trated. The resulting syrup was subjected to column chroma-
tography, yielding a colorless oil (645 mg, 92%). [R]D: +18.3
C
24H30O4S: C, 69.53; H, 7.29. Found: C, 69.33; H, 7.33.
6-Ch lor oh exyl 3,4,6-tr i-O-acetyl-2-deoxy-2-ph th alim ido-
â-D-glu cop yr a n osid e (14). 3,4,6-Triacetyl-2-deoxy-2-phthal-
imido-D-glucopyranosyl bromide (1 g, 2.0 mmol) was dissolved
in dry dichloromethane (20 mL), and lutidine (200 µL, 1.7
mmol), 6-chloro-1-hexanol (420 µL, 3.1 mmol), and freshly
dried 4-Å molecular sieves were added. The mixture was
stirred for 2 h under argon and then cooled in an ice bath.
Silver triflate (565 mg, 2.2 mmol) was added, and the reaction
mixture was stirred in the dark for 3 h. The mixture was
neutralized with triethylamine (2 mL) and filtered through
Celite. The solution was then concentrated and chromato-
graphed in 2:1 EtOAc/pentane to yield a colorless oil (997 mg,
1
1
90%). [R]D: +19.0 (c 1.7, CHCl3). H NMR (300 MHz, CDCl3):
(c 0.7, CHCl3). H NMR (300 MHz, CDCl3): δ 7.60-7.85 (br,
δ 7.79-7.84 (m, 2H, Ar), 7.70-7.74 (m, 2H, Ar), 5.75 (dd, 1H,
J 2,3 ) 10.8 Hz, J 3,4 ) 9.0 Hz, H3), 5.31 (d, 1H, J 1,2 ) 8.5 Hz,
H1), 5.13 (dd, 1H, J 4,5 ) 9.0 Hz, H4), 4.29 (dd, 1H, J 5,6 ) 4.6
Hz, J gem ) 12.2 Hz, H6a), 4.27 (dd, 1H, H2), 4.13 (dd, 1H, J 5,6
4H, Ar), 7.27-7.38 (m, 5H, Ar), 6.92-7.06 (m, 5H, Ar), 5.11
(d, 1H, J 1,2 ) 8.2 Hz, H1), 4.73 (d, 1H, J gem ) 12.2 Hz, CH2-
Ph), 4.60 (AB, 2H, OCH2Ph), 4.52 (d, 1H, OCH2Ph), 4.09-4.24
(m, 2H, H2, H3), 3.72-3.84 (m, 4H, H4, H5, H6a, CH2CH2O),
3.62 (dd, 1H, J 5,6b ) 5.0 Hz, J gem ) 9.8 Hz, H6b), 3.36 (ddd,
1H, J gem ) 9.7 Hz, J vic ) 7.1 Hz, J vic ) 5.9 Hz, CH2CH2O),
3.26 (t, 2H, J ) 6.9 Hz, CH2Cl), 2.85 (s, 1H, J OH,4 ) 2.5 Hz,
) 2.4 Hz, H6b), 3.82 (m, 2H, CH2O, H5), 3.39 (ddd, 1H, J gem
)
9.9 Hz, J vic ) 7.2 Hz, J vic ) 5.6 Hz, CH2O), 3.27 (t, 2H, J ) 6.9
Hz, CH2Cl), 2.07 (s, 3H, CH3CO), 1.99 (s, 3H, CH3CO), 1.82
(s, 3H, CH3CO), 1.39 (m, 4H, OCH2CH2, CH2CH2Cl), 1.11 (m,
4H, OCH2CH2CH2CH2). Anal. Calcd for C26H32NO10: C, 56.37;
H, 5.82; N, 2.53. Found: C, 56.08; H, 5.81; N, 2.47.
OH), 1.30-1.45 (m, 4H, OCH2CH2 CH2CH2Cl), 0.99-1.20 (m,
,
4H, CH2CH2). Anal. Calcd for C34H38NO7: C, 67.15; H, 6.30;
N, 2.30. Found: C, 66.91; H, 6.46; N, 2.27.
6-Ch lor oh exyl 4,6-O-b en zylid en e-2-d eoxy-2-p h t h a l-
im id o-â-D-glu cop yr a n osid e (15). The triacetate 14 (1.0 g,
1.8 mmol) was dissolved in dry methanol (25 mL), and a
catalytic amount of sodium metal (∼10 mg) was added. The
reaction mixture was stirred for 3 h, and AG 50W H+ resin
was added until the solution was neutral on pH paper. The
reaction mixture was then filtered and concentrated. The
resulting white solid was then dissolved in dry acetonitrile (20
mL), and benzaldehyde dimethyl acetal (325 µL, 2.2 mmol)
was added, followed by p-toluenesulfonic acid (50 mg). The
P h en yl 3,4,6-tr i-O-a cetyl-2-d eoxy-1-th io-2-(2′,2′,2′-tr i-
ch lor oeth oxycar bon ylam in o)-â-D-galactopyr an oside (19).
1,3,4,6-Tetra-O-acetyl-2-deoxy-2-(2′,2′,2′-trichloroethoxycarbo-
nylamino)-â-D-galactopyranoside23 (1.23 g, 2.35 mmol) was
dissolved in dichloromethane (20 mL). Thiophenol (480 µL,
4.62 mmol) and BF3‚OEt2 (390 µL, 3.0 mmol) were then added
in succession under argon. After being stirred for 3 h at room
temperature, the reaction mixture was diluted with dichlo-
romethane and washed with saturated sodium bicarbonate
solution. The organic phase was dried over sodium sulfate and

3070 J . Org. Chem., Vol. 65, No. 10, 2000
Nitz and Bundle
concentrated to a yellow oil that was subjected to column
chromatography in 2:1 hexane/EtOAc to give a colorless oil
(1.0 g, 74%) that crystallized on standing. Mp: 117 °C. [R]D:
5.8 Hz, J vic ) 7.32 Hz, CH2CH2O), 3.35 (t, 2H, CH2Cl), 2.02 (s,
3H, CH3CO), 2.01 (s, 3H, CH3CO), 1.94 (s, 3H, CH3CO), 1.29-
1.42 (m, 4H, OCH2CH2, CH2CH2Cl), 0.98-1.1.18 (m, 4H,
OCH2CH2CH2CH2). Anal. Calcd for C49H56Cl4N2O16: C, 54.96;
H, 5.23; N, 2.62. Found: C, 54.94; H, 5.16; N, 2.56.
1
-5.8 (c 1.0, CHCl3). H NMR (300 MHz, CDCl3): δ 7.53-7.48
(m, 2H, Ar), 7.32-7.27 (m, 3H, Ar), 5.38 (d, 1H, J 3,4 ) 3.3 Hz,
H4), 5.18 (dd, 1H, J 2,3 ) 10.7 Hz, H3), 5.01 (d, 1H, J 1,2 ) 8.8
Hz, H1), 4.89 (d, 1H, J NH,2 ) 10.4 Hz, NH), 4.73 (AB, 2H, CH2-
CCl3), 4.17 (dd, 1H, J gem ) 11.4 Hz, J 5,6a ) 7.1 Hz, H6a), 4.11
(dd, 1H, J 5,6 ) 6.1 Hz, H6b), 3.91 (ddd, 1H, H5), 3.89 (ddd,
1H, H2), 2.10 (s, 3H, CH3CO), 2.02 (s, 3H, CH3CO), 1.97 (s,
3H, CH3CO). Anal. Calcd for C21H24Cl3NO9S: C, 44.03; H, 4.22;
N, 2.45. Found: C, 44.12; H, 3.95; N, 2.45.
Meth yl (2-a ceta m id o-3,4,6-tr i-O-a cetyl-2-d eoxy-â-D-ga -
la ctop yr a n osyl)(1f4)-3,6-d i-O-ben zyl-2-d eoxy-2-p h th a l-
im id o-â-D-glu cop yr a n osid e (22). To a solution of the di-
saccharide 20 (746 mg, 0.77 mmol) in 1:1 DMF/AcOH (20 mL)
was added cadmium metal powder (490 mg, 11.5 mmol), and
the reaction mixture was stirred under argon overnight. The
solution was then filtered and concentrated to a yellow oil. The
oil was taken up in methanol (20 mL) and treated with acetic
anhydride (0.5 mL). The solution was stirred for 1 h and then
concentrated to dryness; column chromatography (10:4:1,
EtOAc/hexane/methanol) yielded a white amorphous solid (474
Meth yl (3,4,6-tr i-O-a cetyl-2-d eoxy-2-(2′,2′,2′-tr ich lor o-
eth oxyca r bon yla m in o)-â-D-ga la ctop yr a n osyl)(1f4)-3,6-
d i-O-b e n zyl-2-d e oxy-2-p h t h a lim id o-â-D-glu cop yr a n o-
sid e (20). Methyl 3,6-di-O-benzyl-2-deoxy-2-phthalimido-â-D-
glucopyranoside11 (664 mg, 1.16 mmol) and glycosyl donor 19
(530 mg 1.15 mmol) were added to a round-bottom flask
containing 4-Å molecular sieves, the flask was purged with
argon, and dichloromethane (5 mL) was added. The mixture
was then stirred for 1 h at room temperature, N-iodosuccin-
imide (103 mg, 0.46 mmol) and then silver triflate (20 mg,
0.078 mmol) were added to the reaction flask, and stirring was
continued for 20 min. The reaction mixture was then diluted
with dichloromethane and filtered through Celite. The organic
phase was washed with solutions of sodium bicarbonate and
sodium thiosulfate and concentrated to a yellow oil. Column
chromatography in 2:1 toluene/EtOAc gave a white solid that
was recrystallized (EtOAc/hexane) to give white needles (967
1
mg, 74%). [R]D: +9.6 (c 1.0, CHCl3). H NMR (500 MHz, CD3-
OD): δ 7.66-7.80 (m, 4H, Ar), 7.27-7.45 (m, 5H, Ar), 6.97-
7.00 (m, 2H, Ar), 6.58-6.87 (m, 3H, Ar), 5.28 (dd, 1H, J 3,4
)
3.4 Hz, J 4,5 ) 1.7 Hz, H4′), 5.08 (dd, 1H, J 2,3 ) 11.3 Hz, H3′),
5.03 (d, 1H, J 1,2 ) 8.5 Hz, H1), 4.85 (d, 1H, J gem ) 12.2 Hz,
PhCH2O), 4.77 (d, 1H, J 1,2 ) 8.4 Hz, H1′), 4.72 (d, 1H, J gem
)
11.6 Hz, PhCH2O), 4.64 (d, 1H, PhCH2O), 4.44 (d, 1H,
PhCH2O), 4.25 (dd, 1H, J 2,3 ) 10.7 Hz, J 3,4 ) 8.6 Hz, H3), 4.03-
4.10 (m, 4H, H2′, H4, H6a′, H6b′), 3.97 (dd, 1H, H2), 3.86 (dd,
1H, J gem ) 11.3 Hz, J 5,6 ) 1.8 Hz, H6a), 3.81 (dd, 1H, J 5,6
)
3.8 Hz, H6b), 3.78 (ddd, 1H, J 5,6a ≈ J 5,6b ) 6.7 Hz, H5′), 3.60
(ddd, 1H, J 4,5 ) 9.9 Hz, H5), 3.36 (s, 3H, OMe), 2.30 (s, 3H,
CH3CO), 1.99 (s, 3H, CH3CO), 1.96 (s, 3H, CH3CO), 1.94 (s,
3H, CH3NHCO). Anal. Calcd for C43H48N2O15: C, 62.01; H,
5.81; N, 3.36. Found: C, 61.93; H, 5.65; N, 3.20.
1
mg, 87%). Mp: 83-85 °C. [R]D: +2.5 (c 1.0, CHCl3). H NMR
(500 MHz, CDCl3): δ 7.32-7.76 (m, 9H, Ar), 6.97 (m, 2H, Ar),
6.78-6.86 (m, 3H, Ar), 5.19 (d, 1H, J 3,4 ) 3.3 Hz, H4′), 4.97
(d, 1H, J 1,2 ) 8.2 Hz, H1), 4.92 (d, 1H, J gem ) 12.2 Hz, PhCH2),
4.79 (d, 1H, J gem ) 12.4 Hz, CH2CCl3), 4.76 (d, 1H, J gem ) 12.2
Hz, PhCH2), 4.66 (d, 1H, CH2CCl3), 4.51 (dd, 1H, J 2,3 ) 10.2
6-Ch lor oh exyl (2-a ceta m id o-3,4,6- tr i-O-a cetyl-2-d eoxy-
â-D-ga la ct op yr a n osyl)(1f4)-3,6-d i-O-b en zyl-2-d eoxy-2-
p h th a lim id o-â-D-glu cop yr a n osid e (23). To a solution of 21
(2.2 g, 2.1 mmol) in 1:1 DMF/AcOH (30 mL) was added
cadmium metal powder (1.3 g, 11.5 mmol), and the reaction
mixture was stirred under argon overnight. The solution was
then filtered and concentrated to a yellow oil. The oil was taken
up in methanol (20 mL), and acetic anhydride (1 mL) was
added. The solution was stirred for 1 h and concentrated to a
yellow syrup. Column chromatography (10:4:1, EtOAc/hexane/
methanol) yielded 1.7 g (86%) of a white solid, which was
recrystallized from EtOAc/hexane. Mp: 150 °C. [R]D: +2.0 (c
1.0, CHCl3). 1H NMR (500 MHz, CDCl3): δ 7.56-7.76 (br, 4H,
Ar), 7.40-7.50 (m, 5H, Ar), 6.99-7.00 (m, 2H, Ar), 6.78-6.87
(m, 3H, Ar), 5.21 (d, 1H, J 3,4 ) 3.5 Hz, H4′), 5.04 (d, 1H, d, J 1,2
) 8.4 Hz, H1), 4.91 (d, 1H, J gem ) 12.1 Hz, CH2Ph), 4.77 (d,
1H, J gem ) 12.5 Hz, CH2Ph), 4.58 (dd, 1H, J 2,3 ) 11.3 Hz, J 3,4
) 3.5 Hz, H3′), 4.43 (d, 1H, J 1,2 ) 9.6 Hz, H1′), 4.39 (d, 1H,
J NH,2 ) 8.4 Hz, NH), 4.38 (d, 1H, J gem ) 12.5 Hz, CH2Ph), 4.38
(d, 1H, J gem ) 12.0 Hz, CH2Ph), 4.21 (dd, 1H, J 2,3 ) 10.8 Hz,
J 3,4 ) 8.4 Hz, H3), 4.10 (ddd, 1H, H2′), 4.10 (dd, 1H, H2), 3.98
Hz, H3′), 4.35 (d, 2H, PhCH2O, PHCH2O), 4.22 (d, 1H, J 1,2
)
7.9 Hz, H1′), 4.19 (dd, 1H, J 3,4 ) 8.4 Hz, J 2,3 ) 10.7 Hz, H3),
4.10 (dd, 1H, H2), 3.99 (dd, 1H, J 4,5 ) 9.5 Hz, H4), 3.96 (dd,
1H, J gem ) 11.1 Hz, J 5,6 ) 6.6 Hz, H6a′), 3.85 (dd, 1H, J 5,6
)
7.3 Hz, H6b′), 3.80 (dd, 1H, J gem ) 10.6 Hz, J 5,6 ) 2.4 Hz, H6a),
3.76 (m, 2H, NH, H2′), 3.64 (ddd, 1H, H5′), 3.59 (dd, 1H, J 5,6
) 1.4 Hz, H6b), 3.46 (ddd, 1H, H5), 3.36 (s, 3H, OMe), 2.02 (s,
3H, CH3CO), 2.00 (s, 3H, CH3CO), 1.95 (s, 3H, CH3CO). Anal.
Calcd for C44H47Cl3N2O16: C, 54.70; H, 4.90; N, 2.90. Found:
C, 54.66; H, 4.84; N, 2.81.
6-Ch lor oh exyl (3,4,6-t r i-O-a cet yl-2-d eoxy-2-(2,2,2-t r i-
ch lor oeth oxycar bon ylam in o)-â-D-galactopyr an osyl)(1f4)-
3,6-d i-O-ben zyl-2-d eoxy-2-p h th a lim id o-â-D-glu cop yr a n o-
sid e (21). The phenyl thioglycoside 19 (240 mg, 0.39 mmol)
and 17 (230 mg, 0.38 mmol) were added to a round-bottom
flask containing 4-Å molecular sieves, and the flask was
purged with argon. Dichloromethane (10 mL) was added, and
the mixture was stirred for 1 h at room temperature. N-
Iodosuccinimide (103 mg, 0.46 mmol) and silver triflate (20
mg, 0.078 mmol) were added to the reaction flask, and stirring
was continued for 20 min. The reaction mixture was then
diluted with dichloromethane and filtered through Celite, and
the organic phase was washed with sodium bicarbonate and
sodium thiosulfate solutions, dried over sodium sulfate, and
concentrated to a yellow oil. Column chromatography (2:1,
toluene/EtOAc) gave a white solid that was recrystallized
(EtOAc/hexane) to give needles (396 mg, 93%). Mp: 153 °C.
[R]D: -12.5 (c 0.52, CHCl3). 1H NMR (300 MHz, CDCl3): δ
7.53-7.78 (br, 4H, Ar), 7.37-7.51 (m, 5H, Ar), 6.95-6.97 (m,
2H, Ar), 6.78-6.86 (m, 3H, Ar), 5.20 (dd, 1H, J 3,4 ) 3.5 Hz,
J 4,5 ) 0.9 Hz, H4′), 5.03 (d, 1H, J 1,2 ) 8.4 Hz, H1), 4.90 (d, 1H,
J gem ) 12.1 Hz, CH2Ph), 4.78 (d, 1H, J gem ) 12.1 Hz, CH2CCl3),
4.76 (d, 1H, CH2Ph), 4.66 (d, 1H, CH2CCl3), 4.53 (dd, 1H, J 2,3
) 10.7 Hz, H3′), 4.36 (d, 1H, J gem ) 12.4 Hz, CH2Ph), 4.34 (d,
1H, CH2Ph), 4.24 (d, 1H, J 1,2 ) 7.9 Hz, H1′), 4.18 (dd, 1H, J 2,3
) 10.8 Hz, J 3,4 ) 8.2 Hz, H3), 4.10 (dd, 1H, H2), 3.98 (dd, 1H,
J 4,5 ) 9.6 Hz, H4), 3.94 (d, 1H, J gem ) 11.2 Hz, H6a), 3.87 (dd,
J 5,6b ) 7.3 Hz, H6b), 3.75-3.83 (m, 3H, H2′, H6a′, CH2CH2O),
3.64 (ddd, 1H, J 5,6 ) 6.9 Hz, H5′), 3.58 (d, 1H, J gem ) 10.2 Hz,
(dd, 1H, J 4,5 ) 9.7 Hz, H4), 3.97 (dd, 1H, J 5,6 ) 6.4 Hz, J gem
)
11.5 Hz, H6a′), 3.89 (dd, 1H, J 5,6 ) 6.4 Hz, H6b′), 3.77 (dt, 1H,
J gem ) 9.7 Hz, J vic ) 6.1 Hz, CH2CH2O), 3.68 (m, 2H, H5′, H6a),
3.62 (dd, 1H, J gem ) 10.8 Hz, J 5,6 ) 2.1 Hz, H6b), 3.51 (ddd,
1H, J 5,6a ) 2.4 Hz, H5), 3.31 (ddd, 1H, J vic ) 7.2 Hz, J vic ) 6.0
Hz, CH2CH2O), 3.25 (t, 2H, J ) 6.9 Hz, CH2Cl), 2.02 (s, 3H,
CH3CO), 1.95 (s, 3H, CH3CO), 1.74 (s, 3H, CH3CO), 1.29-1.43
(m, 4H, OCH2CH2, CH2CH2Cl), 0.86-1.16 (m, 4H, OCH2-
CH2CH2CH2). Anal. Calcd for C48H57ClN2O15: C, 61.50; H, 6.13;
N, 2.99. Found: C, 61.25; H, 6.16; N, 2.93.
Met h yl (2-a cet a m id o-4,6-O-b en zylid en e-2-d eoxy-â-D-
galactopyr an osyl)(1f4)-3,6-di-O-ben zyl-2-deoxy-2-ph th al-
im id o-â-D-glu cop yr a n osid e (24). To a solution of 22 (300
mg, 0.36 mmol) in dry methanol (15 mL) was added a catalytic
amount of sodium metal (5 mg). The reaction mixture was
stirred at room temperature for 3 h and then the reaction was
quenched with AG 50W 50 H+ resin; the reaction mixture was
filtered and concentrated to dryness. The white solid was taken
up in dry acetonitrile (15 mL), and benzaldehyde dimethyl
acetal (108 µL, 0.71 mmol) and then p-toluenesulfonic acid (20
mg) were added. The reaction mixture was stirred for 20 min,
neutralized with triethylamine, concentrated, and subjected
to column chromatography (10:4:1, EtOAc/hexane/methanol)
H6b′), 3.45 (d, 1H, H5), 3.32 (ddd, 1H, J gem ) 9.8 Hz, J vic
)

LacdiNac Glycan Chains of Trichinella spiralis
J . Org. Chem., Vol. 65, No. 10, 2000 3071
to yield a white solid (245 mg, 88%). Recrystallization from
EtOAc/hexane gave the title compound. Mp: 123-125 °C. [R]D:
+3.3 (c 1.2, CHCl3). 1H NMR (500 MHz, CD3OD): δ 7.54-
7.78 (br, 4H, Ar), 7.32-7.44 (m, 6H, Ar), 7.02-7.24 (m, 5H,
Ar), 6.94-6.98 (m, 2H, Ar), 6.72-6.76 (m, 2H, Ar), 5.84 (d,
1H, J NH,2 ) 6.8 Hz, NH), 5.47 (s, 1H, CHO2Ph), 4.89 (d, 1H,
J gem ) 12.8 Hz, PhCH2O), 4.99 (d, 1H, J 1,2 ) 7.9 Hz, H1), 4.79
(d, 1H, J gem ) 11.7 Hz, PhCH2O), 4.57 (d, 1H, J 1,2 ) 8.6 Hz,
H1′), 4.55 (d, 1H, J gem ) 12.1 Hz, PhCH2O), 4.51 (d, 1H, J gem
) 12.7 Hz, PhCH2O), 4.29 (dd, 1H, J 2,3 ) 8.2 Hz, J 3,4 ) 10.7
Hz, H3), 4.24 (d, 1H, J gem ) 12.4 Hz, H6a′), 4.11 (dd, 1H, H2),
4.09 (dd, 1H, J 3,4 ) 3.5 Hz, H4′), 4.01 (dd, 1H, J 4,5 ) 9.3 Hz,
H3′), 3.32 (dt, 1H, J vic ) 5.6 Hz, CH2CH2O), 2.97 (t, 2H, J )
7.0 Hz, CH2N3), 3.25 (s, 1H, H5′), 1.88 (s, 3H, CH3CO), 1.28-
1.42 (m, 2H, OCH2CH2), 1.14-1.23 (m, 2H, CH2CH2N3), 0.97-
1.10 (m, 4H, OCH2CH2CH2CH2). IR (cast): N3 stretch, 2094
cm-1. Anal. Calcd for C49H55N3O12: C, 64.96; H, 6.12; N, 7.73.
Found: C, 64.73; H, 6.13; N, 7.65.
Meth yl (4-O-ben zyl-3,6-d id eoxy-2-O-p iva loyl-r ibo-h ex-
opyr an osyl)(1f3)(2-acetam ido-4,6-O-ben zyliden e-2-deoxy-
â-D-ga la ct op yr a n osyl)(1f4)-3,6-d i-O-b en zyl-2-d eoxy-2-
p h th a lim id o-â-D-glu cop yr a n osid e (27). A solution of 24 (85
mg, 0.11 mmol), 13 (49 mg, 0.119 mmol), and freshly activated
4-Å sieves in dichloromethane (3 mL) was stirred for 1 h. The
reaction mixture was cooled in an ice bath, and N-iodosuccin-
imide (29 mg, 129 mmol) and then silver triflate (10 mg) were
added. The ice bath was removed, and the reaction mixture
was allowed to warm to room temperature. After 30 min, the
reaction mixture was filtered through Celite, and the solids
were washed with dichloromethane. The combined filtrate was
washed with thiosulfate and bicarbonate solutions, dried over
sodium sulfate, and concentrated. Chromatography in 5:2
toluene/EtOAc yielded a clear amorphous solid (95 mg, 85%).
H4), 3.91 (dd, 1H, H6b′), 3.86 (dd, 1H, J gem ) 10.8 Hz, J 5,6
)
3.6 Hz, H6a), 3.75 (dd, 1H, J 5,6 ) 3.6 Hz, H6b), 3.64 (ddd, 1H,
H5), 3.92 (ddd, 1H, H2′), 3.59 (dd, 1H, J 2,3 ) 10.6 Hz, H3′),
3.37 (s, 3H, OMe), 3.25 (s, 1H, H5′), 1.89 (s, 3H, CH3CONH).
Anal. Calcd for C44H46N2O12 + 0.5 H2O: C, 65.74; H, 5.89; N,
3.48. Found: C, 65.75; H, 5.76; N, 3.44. HR electrospray m/z:
calcd, 817.29484; found, 817.29467.
6-Ch lor oh exyl (2-acetam ido-4,6-O-ben zyliden e-2-deoxy-
â-D-ga la ct op yr a n osyl)(1f4)-3,6-d i-O-b en zyl-2-d eoxy-2-
p h th a lim id o-â-D-glu cop yr a n osid e (25). To a solution of 23
(1.31 g, 1.4 mmol) in dry methanol (25 mL) was added a small
piece of sodium metal (5 mg). The reaction mixture was stirred
at room temperature for 3 h and then the reaction was
quenched with Ag 50W 50 H+ resin; the reaction mixture was
filtered and concentrated to dryness. The white solid was then
taken up in dry acetonitrile, and benzaldhyde dimethyl acetal
(320 µL, 2.1 mmol) and then p-toluenesulfonic acid (10 mg)
were added. The reaction mixture was stirred for 20 min,
neutralized with triethylamine, concentrated, and subjected
to column chromatography (10:4:1, EtOAc/hexane/methanol)
to give a white solid (993 mg, 79%), which could be recrystal-
lized from EtOAc/hexane. Mp: 102-103 °C. [R]D: -4.1 (c 1.0,
CHCl3). 1H NMR (500 MHz, CDCl3): δ 7.56-7.76 (br, 4H, Ar),
7.34-7.43 (m, 5H, Ar), 7.16-7.21 (m, 5H, Ar), 6.96-6.98 (m,
2H, Ar), 6.72-6.86 (m, 3H, Ar), 5.85 (d, 1H, J NH,2 ) 6.9 Hz,
NHAc), 5.48 (s, 1H, PhCHO2), 5.06 (d, 1H, J 1,2 ) 8.6 Hz, H1),
4.91 (d, 1H, J gem ) 12.7 Hz, OCH2Ph), 4.79 (d, 1H, J gem ) 11.8
Hz, OCH2Ph), 4.56 (d, 1H, J 1,2 ) 8.7 Hz, H1′), 4.54 (d, 1H,
J gem ) 12.1 Hz, OCH2Ph), 4.52 (d, 1H, d, J ) 12.8 Hz, OCH2-
Ph), 4.28 (dd, 1H, J 2,3 ) 10.7 Hz, J 3,4 ) 8.7 Hz, H3), 4.24 (d,
1H, J gem ) 12.4 Hz, H6a′), 4.11 (dd, 1H, H2), 4.08 (d, 1H, J 3,4
) 3.3 Hz, H4′), 3.97 (dd, 1H, J 4,5 ) 8.4 Hz, H4), 3.90-3.94 (m,
2H, H2′, H6b′), 3.84 (dd, 1H, J 5,6 ) 3.1 Hz, J gem ) 10.8 Hz,
H6a), 3.76 (dt, 1H, J gem ) 9.8 Hz, J vic ) 5.8 Hz, CH2CH2O),
3.74 (dd, 1H, J 5,6 ) 3.4 Hz, H6b), 3.58 (dd, 1H, H5), 3.58 (dd,
1H, J 2,3 ) 10.7 Hz, H3′), 3.32 (dt, 1H, J ) 6.1 Hz, CH2CH2O),
3.25 (d, 1H, J 5,6b ) 4.6 Hz, H5′), 3.25 (t, 2H, J ) 6.9 Hz, CH2-
Cl), 1.88 (s, 3H, CH3CO), 1.29-1.43 (m, 4H, OCH2CH2,
CH2CH2Cl), 0.97-1.16 (m, 4H, CH2CH2), Anal. Calcd for
1
[R]D: +4.2 (c 1.0, CHCl3). H (500 MHz, CDCl3): δ 7.56-7.76
(m, 4H, Ar), 7.12-7.44 (m, 15H, Ar), 6.91-6.93 (m, 2H, Ar),
6.79-6.82 (m, 1H, Ar), 6.71 (m, 2H, Ar), 5.59 (d, 1H, J NH,2
)
7.0 Hz, NH), 5.47 (s, 1H, PhCHO2), 5.17 (d, 1H, J 1,2 ) 8.2 Hz,
H1′), 5.00 (d, 1H, J gem ) 12.5 Hz, PhCH2O), 4.99 (d, 1H, J 1,2
)
8.2 Hz, H1), 4.69 (d, 1H, J gem ) 11.8 Hz, PhCH2O), 4.65 (d,
1H, J 1,2 ) 8.6 Hz, H1′′), 4.64 (d, 1H, J gem ) 11.9 Hz, PhCH2O),
4.60 (d, 1H, J gem ) 11.5 Hz, PhCH2O), 4.58 (dd, 1H, J 2,3 ) 9.8
Hz, J 3,4 ) 3.8 Hz, H3′), 4.57 (d, 1H, J gem ) 12.8 Hz, PhCH2O),
4.54 (ddd, 1H, J 2,3ax ) 11.1 Hz, J 2,3eq ) 5.2 Hz, H2′′), 4.42 (d,
1H, J gem ) 11.4 Hz, PhCH2O), 4.28 (dd, 1H, J gem ) 12.8 Hz,
J 5,6a ) 1.4 Hz, H6a′), 4.26 (d, 1H, H4′), 4.20-4.24 (m, 2H, H3,
H4), 4.01 (dd, 1H, J 2,3 ) 10.4 Hz, H2), 3.96 (dd, 1H, J 5,6b ) 1.5
Hz, H6b′), 3.81 (dd, 1H, J gem ) 10.8 Hz, J 5,6a ) 1.5 Hz, H6a),
3.76 (dd, 1H, J 5,6b ) 3.7 Hz, H6b), 3.59 (ddd, 1H, J 4,5 ) 9.5
Hz, H5), 3.49 (dt, 1H, J 4,5 ) 8.9 Hz, J 5,6 ) 6.3 Hz, H5′′), 3.48
(dd, 1H, H2′), 3.36 (s, 3H, OMe), 3.29 (dd, 1H, H5′), 3.23 (ddd,
1H, J 3ax,4 ) 10.7 Hz, J 3eq,4 ) 4.6 Hz, H4′′), 2.62 (ddd, 1H, J gem
) 12.1 Hz, H3eq′′), 1.97 (s, 3H, CH3CONH), 1.37 (ddd, 1H,
H3ax′′), 1.33 (d, 3H, H6′′), 1.20 (s, 9H, (CH3)3CO). Anal. Calcd
for C62H70N2O16: C, 67.74; H, 6.42; N, 2.55. Found: C, 66.98;
H, 6.15; N, 2.65. HR electrospray m/z: calcd, 1099.48036;
found, 1099.48045.
6-Azid oh exyl (4-O-b en zyl-3,6-d id eoxy-2-O-p iva loyl-
r ibo-h exopyr an osyl)(1f3)(2-acetam ido-4,6-O-ben zyliden e-
2-d eoxy-â-D-ga la ct op yr a n osyl)(1f4)-3,6-d i-O-b en zyl-2-
d eoxy-2-p h th a lim id o-â-D-glu cop yr a n osid e (28). A solution
of 26 (200 mg, 0.22 mmol), 13 (100 mg, 0.24 mmol), and freshly
activated 4-Å sieves in dichloromethane (4 mL) was stirred
for 1 h. The reaction mixture was then cooled in an ice bath,
and N-iodosuccinimde (65 mg) and then silver triflate (10 mg)
were added. The ice bath was removed, and the reaction
mixture was allowed to warm to room temperature. After 30
min, the reaction mixture was filtered through Celite, and the
solids were washed with dichloromethane. The combined
filtrate was washed with thiosulfate and bicarbonate solutions,
dried over sodium sulfate, and concentrated to a yellow oil.
Chromatography in 5:2 toluene/EtOAc yielded 216 mg (81%)
of a colorless amorphous solid. [R]D: -5.4 (c 0.5, CHCl3). 1H
NMR (600 MHz, CDCl3): δ 7.80-7.54 (br, 4H, Ar), 7.40-7.10
(m, 15H, Ar), 6.94-6.93 (m, 2H, Ar), 6.74-6.70 (m, 3H, Ar),
5.56 (d, 1H, J NH,2 ) 7.0 Hz, NHAc), 5.43 (s, 1H, O2CHPh), 5.14
(d, 1H, J 1,2 ) 8.2 Hz, H1′), 5.05 (d, 1H, J 1,2 ) 8.6 Hz, H1), 4.99
(d, 1H, J gem ) 12.8 Hz, OCH2Ph), 4.68 (d, 1H, J gem ) 12.1 Hz,
C
49H55ClN2O12: C, 65.43; H, 6.16; N, 3.11. Found: C, 65.16;
H, 6.1; N, 3.07.
6-Azid oh exyl (2-a ceta m id o-4,6-O-ben zylid en e-2-d eoxy-
â-D-ga la ct op yr a n osyl)(1f4)-3,6-d i-O-b en zyl-2-d eoxy-2-
p h th a lim id o-â-D-glu cop yr a n osid e (26). To a solution of 25
(993 mg, 1.10 mmol) in DMSO (10 mL) was added sodium
azide (400 mg, 6.2 mmol). The mixture was heated to 60 °C
overnight. The solution was then diluted with dichloromethane
and washed three times with water. After drying, the solution
was concentrated and crystallized from EtOAc/hexane to give
26 (946 mg, 96%). Mp: 108-111 °C. [R]D: -5.4 (c 0.52, CHCl3).
1H NMR (500 MHz, CDCl3): δ 7.56-7.76 (br, 4H, Ar), 7.34-
7.43 (m, 5H, Ar), 7.16-7.21 (m, 5H, Ar), 6.96-6.98 (m, 2H,
Ar), 6.72-6.86 (m, 3H, Ar), 5.85 (d, 1H, J NH,2 ) 6.9 Hz, NHAc),
5.48 (s, 1H, PhCHO2), 5.06 (d, 1H, J 1,2 ) 8.6 Hz, H1), 4.91 (d,
1H, J gem ) 12.7 Hz, CH2Ph), 4.79 (d, 1H, J gem ) 11.8 Hz, CH2-
Ph), 4.56 (d, 1H, J 1,2 ) 8.7 Hz, H1′), 4.54 (d, 1H, J gem ) 12.1
Hz, CH2Ph), 4.52 (d, 1H, J gem ) 12.8 Hz, CH2Ph), 4.28 (dd,
1H, J 2,3 ) 8.7 Hz, J 3,4 ) 10.4 Hz, H3), 4.24 (d, 1H, J gem ) 11.3
Hz, H6a′), 4.11 (dd, 1H, H2), 4.04 (d, 1H, J 3,4 ) 3.2 Hz, H4′),
3.97 (dd, 1H, H4), 3.90-3.94 (m, 2H, H2′, H6b′), 3.84 (dd, 1H,
J gem ) 10.8 Hz, J 5,6 ) 3.1 Hz, H6a), 3.76 (dt, 1H, J gem ) 9.8
Hz, J vic ) 5.8 Hz, CH2CH2O), 3.74 (dd, 1H, J 5,6 ) 3.4 Hz, H6b),
3.62 (ddd, 1H, J 4,5 ) 9.6 Hz, H5), 3.58 (dd, 1H, J 2,3 ) 10.7 Hz,
OCH2Ph), 4.66 (d, 1H, J 1,2 ) 7.7 Hz, H1′′), 4.62 (d, 1H, J gem
)
12.1 Hz, OCH2Ph), 4.60-4.52 (m, 2H, H2′′, H3′), 4.58 (d, 1H,
J gem ) 11.5 Hz, OCH2Ph), 4.53 (d, 1H, J gem ) 12.8 Hz, OCH2-
Ph), 4.39 (d, 1H, J gem ) 11.5 Hz, OCH2Ph), 4.28 (dd, 1H, J 2,3
) 8.2 Hz, J 3,4 ) 10.6 Hz, H3), 4.26 (d, 1H, J gem ) 10.6 Hz,
H6a′), 4.20 (d, 1H, J 3,4 ) 3.5 Hz, H4′), 4.15-4.12 (m, 2H, H4,
H2), 3.87 (d, 1H, H6b′), 3.80 (d, 1H, J gem ) 9.9 Hz, H6a), 3.76
(dt, 1H, J gem ) 9.9 Hz, J vic ) 6.0 Hz, OCH2CH2), 3.72 (dd, 1H,
J 5,6 ) 4.2 Hz, H6b), 3.59 (dd, 1H, J 4,5 ) 10.6 Hz, H5), 3.48 (dd,
1H, J 2,3 ) 6.4 Hz, H2′), 3.46 (dq, 1H, J 5,6 ) 5.8 Hz, H5′′), 3.33

3072 J . Org. Chem., Vol. 65, No. 10, 2000
Nitz and Bundle
(dt, 1H, J vic ) 7.1 Hz, OCH2CH2), 3.22 (s, 1H, H5′), 3.21 (1H,
J 5,6 ) 2.9 Hz, H5′′), 3.35 (ddd, 1H, J 2,3eq ) 5.0 Hz, J 2,3ax ) 12.2
Hz, H2′′), 3.23 (s, 1H, H5′), 3.23 (t, 2H, J vic ) 7.0 Hz, CH2N3),
3.14 (ddd, 1H, J 3,4 ) 4.6 Hz, J 3,4 ) 11.0 Hz, H4′′), 2.42 (ddd,
1H, J gem ) 12.1 Hz, H3eq′′), 1.94 (s, 3H, NHCOCH3), 1.82 (s,
3H, NHCOCH3), 1.58-1.52 (m, 4H, OCH2CH2, CH2CH2N3),
1.39-1.36 (m, 4H, OCH2CH2CH2CH2), 1.35 (ddd, 1H, H3ax′′),
1.27 (d, 3H, H6′′). Anal. Calcd for C56H71N5O14 + H2O: C,
63.68; H, 6.97; N, 6.63. Found: C, 63.82; H, 6.94; N, 6.63.
Meth yl (4-O-ben zyl-3,6-d id eoxy-a r a bin o-h exop yr a n o-
syl)(1f3)(2-a ceta m id o-4,6-O-ben zylid en e-2-d eoxy-â-D-ga -
la ct op yr a n osyl)(1f4)-2-a ce t a m id o-3,6-d i-O-b e n zyl-2-
d eoxy-â-D-glu cop yr a n osid e (31). Compound 29 (75 mg) was
dissolved in dry DMSO (2 mL) and acetic anhydride (0.5 mL).
The reaction mixture was stirred overnight and concentrated
to dryness. The yellow solid was dissolved in DMF (0.5 mL)
and then diluted with dry THF (10 mL). The reaction mixture
was cooled to -78 °C, and 1 M L-selectride (500 µL) in THF
was added dropwise. The reaction mixture was allowed to
warm to room temperature, and the reaction was quenched
with acetone. Silica gel was then added to the solution, and
the volatiles were removed under vacuum. The silica gel was
then slurried onto the top of a silica column, and the product
was eluted with 4% methanol in dichloromethane to give 31
(62 mg, 82%). [R]D: +4.3 (c 0.67 CH3OH). 1H NMR (500 MHz,
CD3OD): δ 7.18-7.46 (m, 20H, Ar), 5.17 (d, 1H, J gem ) 11.9
Hz, PhCH2O), 5.55 (s, 1H, PhCHO2), 4.74 (d, 1H, J 1,2 ) 8.4
Hz, H1′), 4.71 (d, 1H, J gem ) 11.9 Hz, PhCH2O), 4.68 (d, 1H,
J gem ) 11.9 Hz, PhCH2O), 4.61 (d, 1H, J gem ) 11.9 Hz,
ddd, J 3eq,4 ) 4.7 Hz, J 3ax,4 ) 12.1 Hz, H4′′), 2.97 (t, 3H, J vic
)
7.1 Hz, CH2N3), 2.61 (1H, ddd, J gem ) 12.1 Hz, J 2,3 ) 4.9 Hz,
H3eq′′), 1.95 (s, 3H, NHCOCH3), 1.41-1.28 (m, 2H, OCH2CH2),
1.33 (ddd, 1H, J 2,3 ) 12.0 Hz, H3ax′′), 1.31 (d, 3H, H6′′), 1.25-
1.17 (m, 2H, CH2CH2N3), 1.17 (s, 9H, COC(CH3)3), 1.11-1.00
(m, 4H, OCH2CH2CH2CH2). Anal. Calcd for C67H79N5O16
+
H2O: C, 65.51; H, 6.65; N, 5.70. Found: C, 65.51; H, 6.66; N,
5.68. HR electrospray m/z: calcd for C67H80N5O16, 1210.5600;
found, 1210.5596.
Meth yl (4-O-ben zyl-3,6-d id eoxy-r ibo-h exop yr a n osyl)-
(1f3)(2-a ceta m id o-4,6-O-ben zylid en e-2-d eoxy-â-D-ga la c-
top yr a n osyl)(1f4)-2-a ceta m id o-3,6-d i-O-ben zyl-2-d eoxy-
â-D-glu cop yr a n osid e (29). The protected trisaccharide 27 (95
mg, 0.086 mmol) was dissolved in butanol (4 mL) and ethyl-
enediamine (1 mL). The solution was heated to 110 °C for 16
h and then concentrated to a yellow oil. The oil was taken up
in methanol, 500 µL of acetic anhydride was added, and the
mixture was stirred for 1 h and then concentrated to dryness.
The oil was dissolved in dry methanol (10 mL), and sodium
metal (10 mg) was added. The solution was refluxed for an
additional 12 h, neutralized with Ag 50W 50 H+ resin, filtered,
and concentrated to dryness. The resulting oil was chromato-
graphed in 10:4:1 EtOAc/hexane/methanol, yielding a white
amorphous solid 29 (68 mg, 85%). [R]D: +6.6 (c 0.45, CH3OH).
1H (600 MHz, CD3OD): δ 7.18-7.44 (m, 20H, Ar), 5.33 (s, 1H,
PhCHO2), 5.16 (d, 1H, J gem ) 12.1 Hz, PhCH2O), 4.74 (d, 1H,
J 1,2 ) 8.2 Hz, H1′), 4.67 (d, 1H, J gem ) 11.7 Hz, PhCH2O), 4.62
(d, 1H, J gem ) 11.5 Hz, PhCH2O), 4.61 (d, 1H, J gem ) 11.9 Hz,
PhCH2O), 4.47 (d, 1H, J gem ) 11.5 Hz, PhCH2O), 4.47 (d, 1H,
J gem ) 11.5 Hz, PhCH2O), 4.32 (d, 1H, J 1,2 ) 8.1 Hz, H1), 4.31
(d, 1H, J 1,2 ) 7.5 Hz, H1′′), 4.26 (d, 1H, J 3,4 ) 3.5 Hz, H4′),
4.14 (dd, 1H, J gem ) 12.1 Hz, J 5,6 ) 1.7 Hz, H6a′), 4.10 (dd,
1H, J 2,3 ) 10.6 Hz, H2′), 3.96 (dd, 1H, J 5,6 ) 2.2 Hz, H6b′),
PhCH2O), 4.58 (d, 1H, J 1,2 < 1 Hz, H1′′), 4.57 (d, 1H, J gem
)
11.5 Hz, PhCH2O), 4.43 (d, 1H, J gem ) 11.5 Hz, PhCH2O), 4.32
(d, 1H, J 1,2 ) 8.2 Hz, H1), 4.30 (dd, 1H, J 3,4 ) 3.5 Hz, H4′),
4.14 (dd, 1H, J gem ) 12.4 Hz, J 5,6 ) 1.4 Hz, H6a′), 4.09 (dd,
1H, J 2,3 ) 8.7 Hz, H2′), 3.97 (dd, 1H, J 5,6 ) 2.0 Hz, H6b′), 3.95
(dd, 1H, J 4,5 ) 6.9 Hz, J 3,4 ) 8.2 Hz, H4), 3.93 (dd, 1H, H3′),
3.84 (dd, 1H, J gem ) 11.6 Hz, J 5,6a ) 2.4 Hz, H6a), 3.80 (dd,
1H, J 2,3 ) 9.7 Hz, H2), 3.79 (dd, 1H, J 5,6b ) 4.2 Hz, H6b), 3.76
(ddd, 1H, J 2,3a ≈ J 2,3b ) 3.4 Hz, H2′′), 3.66 (dd, 1H, H3), 3.51
(ddd, 1H, H5), 3.43 (s, 3H, OMe), 3.38-3.48 (m, 2H, H5′′, H4′′),
3.23 (s, 1H, H5′), 2.31 (ddd, 1H, J gem ) 13.5 Hz, H3eq′′), 1.94
(s, 3H, CH3NHCO), 1.82 (s, 3H, CH3NHCO), 1.48 (ddd, 1H,
H3ax′′), 1.30 (d, 3H, J 5,6 ) 6.1 Hz, H6′′). 13C NMR (500 MHz,
3.95 (dd, 1H, J 4,5 ≈ J 3,4 ) 8.5 Hz, H4), 3.91 (dd, 1H, dd, J 2,3
)
11.0 Hz, J 3,4 ) 3.1 Hz, H3′), 3.83 (dd, 1H, J gem ) 11.2 Hz, J 5,6
) 2.4 Hz, H6b), 3.81 (dd, 1H, J 2,3 ) 9.1 Hz, H2), 3.79 (dd, 1H,
J 5,6 ) 4.4 Hz, H6a), 3.65 (dd, 1H, H3), 3.51 (1H, ddd, H5), 3.40
(dq, 1H, J 4,5 ) 9.0 Hz, J 5,6 ) 6.0 Hz, H5′′), 3.34 (ddd, 1H, J 2,3ax
) 12.5 Hz, J 2,3eq ) 7.7 Hz, H2′′), 3.43 (s, 3H, OMe), 3.23 (s,
1H, H5′), 3.13 (ddd, 1H, J 3ax,4 ) 11.0 Hz, J 3eq,4 ) 4.6 Hz, H4′′),
2.42 (1H, ddd, J gem ) 12.0 Hz, H3eq′′), 1.94 (s, 3H, CH3NHCO),
1.82 (s, 3H, CH3NHCO), 1.33 (ddd, 1H, H3ax′′), 1.27 (d, 3H,
H6′′). Anal. Calcd for C51H62N2O14 + H2O: C, 64.82; H, 6.83;
N, 2.96. Found: C, 64.83; H, 6.64; N, 2.92. HR electrospray
m/z: calcd for C51H62N2O14Na, 949.4098; found, 949.4088.
6-Azid oh exyl (4-O-ben zyl-3,6-d id eoxy-r ibo-h exop yr a n -
osyl)(1f3)(2-a cet a m id o-4,6-O-b en zylid en e-2-d eoxy-â-D-
ga la ct op yr a n osyl)(1f4)-2-a cet a m id o-3,6-d i-O-b en zyl-2-
deoxy-â-D-glu copyr an oside (30). The protected trisaccharide
28 (176 mg, 0.145 mmol) was dissolved in butanol (4 mL) and
ethenediamine (1 mL). The solution was heated to 110 °C for
12 h and then concentrated to a yellow oil. The oil was taken
up in methanol, and acetic anhydride (500 µL) was added; the
mixture was then stirred for 1 h. After concentration of the
reaction mixture, the resulting oil was dissolved in dry
methanol (10 mL), and sodium metal (10 mg) was added. The
solution was refluxed for an additional 12 h, neutralized with
Ag 50W 50 H+ resin, filtered, and concentrated. The remaining
oil was chromatographed in 10:4:1 EtOAc/hexane/methanol,
yielding a white amorphous solid (132 mg, 88%). [R]D: -5.4 (c
0.52, CHCl3). 1H NMR (500 MHz, CD3OD): δ 7.43-7.17 (m,
20H, Ar), 5.52 (s, 1H, O2CHPh), 5.15 (d, 1H, J gem ) 11.9 Hz,
CD3OD): δ 101.72 (J C1-H1 ) 162 Hz, C1′, â), 103.20 (J C1-H1
)
161 Hz, C1, â), 140.10 (J C1-H1 ) 158 Hz, C1′′, â). Anal. Calcd
for C51H62N2O14 + H2O: C, 64.82; H, 6.83; N, 2.96. Found: C,
64.77; H, 6.80; N, 2.95. HR electrospray m/z: calcd for
C
51H63N2O14, 927.4279; found, 927.4294.
6-Azid oh exyl (4-O-ben zyl-3,6-d id eoxy-a r a bin o-h exop y-
r a n osyl)(1f3)(2-a ceta m id o-4,6-O-ben zylid en e-2-d eoxy-â-
D-ga la ct op yr a n osyl)(1f4)-2-a cet a m id o-3,6-d i-O-b en zyl-
2-d eoxy-â-D-glu cop yr a n osid e (32). The alcohol 30 (75 mg,
0.072 mmol) was dissolved in 2:1 dimethyl sulfoxide/acetic
anhydride (6 mL), and the mixture was stirred overnight under
argon. The resulting yellow solution was concentrated to
dryness, and the yellow solid was taken up in DMF (0.5 mL)
and diluted with tetrahydrofuran (10 mL). The solution was
then cooled to -78 °C and treated dropwise with 20 equiv of
a 1 M L-selectride solution in THF (150 µL). The reaction
mixture was allowed to warm to -20 °C over 20 min, the
reaction was quenched with ethylenediamine (1 mL), and the
reaction mixture was allowed to warm to room temperature.
Silica gel was added to the reaction mixture, and the volatiles
were removed under vaccum. The silica was slurried onto the
top of a column, and the product was eluted with 4% methanol
in dichloromethane to give 32 (61 mg, 81%) as an amorphous
solid. [R]D: +8.9 (c 0.45, CH3OH). 1H NMR (500 MHz, CD3-
OD): δ 7.46-7.18 (m, 20H, Ar), 5.55 (s, 1H, O2CHPh), 5.17
(d, 1H, J gem ) 12.1 Hz, OCH2Ph), 4.74 (d, 1H, J 1,2 ) 8.4 Hz,
H1′), 4.71 (d, 1H, J gem ) 11.7 Hz, OCH2Ph), 4.68 (d, 1H, J gem
) 11.7 Hz, OCH2Ph), 4.61 (d, 1H, J gem ) 11.7 Hz, OCH2Ph),
4.59 (s, 1H, H1′′), 4.58 (d, 1H, J gem ) 11.6 Hz, OCH2Ph), 4.43
(d, 1H, J gem ) 11.6 Hz, OCH2Ph), 4.41 (d, 1H, J 1,2 ) 8.1 Hz,
H1), 4.30 (d, 1H, J 3,4 ) 3.4 Hz, H4′), 4.14 (dd, 1H, J gem ) 12.4
Hz, J 5,6 ) 1.4 Hz, H6a′), 4.10 (dd, 1H, J 2,3 ) 8.6 Hz, H2′), 3.96
(dd, 1H, J 5,6 ) 1.7 Hz, H6b′), 3.94 (dd, 1H, J 4,5 ≈ J 3,4 ) 8.6 Hz,
H4), 3.93 (dd, 1H, H3′), 3.86-3.78 (m, 3H, H6a, H6b, OCH2-
OCH2Ph), 4.73 (d, 1H, J 1,2 ) 8.2 Hz, H1′), 4.68 (d, 1H, J gem
)
11.9 Hz, OCH2Ph), 4.67 (d, 1H, J gem ) 11.8 Hz, OCH2Ph), 4.62
(d, 1H, J gem ) 11.4 Hz, OCH2Ph), 4.60 (d, 1H, J gem ) 11.8 Hz,
OCH2Ph), 4.47 (d, 1H, J gem ) 11.6 Hz, OCH2Ph), 4.40 (d, 1H,
J 1,2 ) 8.1 Hz, H1), 4.30 (d, 1H, J 1,2 ) 7.6 Hz, H1′′), 4.25 (d,
1H, J 3,4 ) 3.3 Hz, H4′), 4.14 (dd, 1H, J gem ) 12.2 Hz, J 5,6 ) 1.4
Hz, H6a′), 4.09 (dd, J 2,3 ) 11.0 Hz, H2′), 3.95 (dd, 1H, J 5,6
)
1.4 Hz, H6′b′), 3.94 (dd, 1H, J 3,4 ≈ J 4,5 ) 8.5 Hz, H4), 3.90 (dd,
1H, J 2,3 ) 11.1 Hz, J 3,4 ) 3.4 Hz, H3′), 3.84-3.76 (m, 4H, H6a,
H6b, H2, CH2CH2O), 3.67 (dd, 1H, J 2,3 ) 9.6 Hz, H3), 3.50
(ddd, J 5,6a ) 2.4 Hz, J 5,6b ) 4.6 Hz, H5), 3.45 (ddd, 1H, J gem
)
9.8 Hz, J vic ) 6.4 Hz, CH2CH2O), 3.40 (dq, 1H, J 4,5 ) 9.0 Hz,

LacdiNac Glycan Chains of Trichinella spiralis
J . Org. Chem., Vol. 65, No. 10, 2000 3073
CH2), 3.81 (m, 1H, H2), 3.76 (dd, 1H, J 2,3a ≈ J 2,3b ) 4.0 Hz,
H2′), 3.91-3.87 (m, 3H, H2′′, H3′, OCH2CH2), 3.84 (dd, 1H,
J gem ) 12.1 Hz, J 5,6 ) 2.0 Hz, H6a), 3.80 (dd, 1H, J gem ) 11.7
Hz, J 5,6 ) 8.2 Hz, H6a′), 3.76 (dd, 1H, J 5,6 ) 3.9 Hz, H6b′),
3.74 (dd, 1H, H5′), 3.71 (ABX, 2H, H2, H3), 3.65 (dd, 1H, J 5,6
) 5.7 Hz, H6b), 3.63 (ABX, 1H, H4), 3.57 (dt, 1H, J gem ) 10.1
Hz, J vic ) 6.4 Hz, OCH2CH2), 3.55 (ddd, 1H, J 3ax,4 ) 11.5 Hz,
J 3eq,4 ) 4.8 Hz, J 4,5 ) 9.3 Hz, H4′′), 3.51 (ddd, 1H, J 4,5 ) 7.7
H2′′), 3.68 (dd, 1H, J 2,3 ) 9.7 Hz, H3), 3.51 (ddd, 1H, J 5,6
)
2.3 Hz, J 5,6 ) 4.6 Hz, H5), 3.48-3.38 (m, 3H, OCH2CH2, H4′′,
H5′′), 3.23 (t, 2H, J vic ) 6.9 Hz, CH2N3), 3.23 (s, 1H, H5′), 2.31
(ddd, 1H, J gem ) 13.6 Hz, J 3,4 ) 3.8 Hz, H3eq′′), 1.94 (s, 3H,
CH3CONH), 1.83 (s, 3H, CH3CONH), 1.58-1.52 (m, 4H,
OCH2CH2CH2CH2CH2), 1.48 (ddd, 1H, J 3,4 ) 10.4 Hz, H3ax′′),
1.40 (m, 4H, OCH2CH2CH2CH2), 1.30 (d, 3H, J 5,6 ) 5.8 Hz,
H6′′). Anal. Calcd for C56H71N5O14 + 0.5 H2O: C, 64.23; H,
6.93; N, 6.69. Found: C, 64.15; H, 6.58; N, 6.42. HR electro-
spray m/z: calcd for C56H72N5O14, 1038.5075; found, 1038.5083.
Meth yl (3,6-d id eoxy-a r a bin o-h exop yr a n osyl)(1f3)(2-
a cet a m id o-2-d eoxy-â-D-ga la ct op yr a n osyl)(1f4)-2-a cet -
a m id o-2-d eoxy-â-D-glu cop yr a n osid e (2). The trisaccharide
31 (55 mg) was hydrogenated for 16 h over 20% paladium
hydroxide on carbon (10 mg) in methanol. After filtration, the
product was dissolved in a minimal amount of methanol and
allowed to crystallize in an atmosphere of ethanol. The fine
crystals were collected, dissolved in water, and lyophilized to
give 2 as a white solid (30 mg, 88%). [R]D: -26.9 (c 0.36, H2O).
1H NMR (600 MHz, D2O): δ 4.70 (d, 1H, J 1,2 < 1 Hz, H1′′),
4.58 (d, 1H, J 1,2 ) 8.4 Hz, H1′), 4.44 (d, 1H, J 1,2 ) 8.1 Hz, H1),
4.13 (d, 1H, J 3,4 ) 3.1 Hz, H4′), 4.04 (dd, 1H, J 2,3 ) 10.6 Hz,
H2′), 3.91 (dd, 1H, J 2,3ax ≈ J 2,3eq ) 3.3 Hz, H2′′), 3.89 (dd, 1H,
J 3,4 ) 2.9 Hz, H3′), 3.86 (dd, 1H, J gem ) 12.1 Hz, J 5,6 ) 2.0 Hz,
H6b), 3.80 (dd, 1H, J gem ) 11.7 Hz, J 5,6 ) 8.2 Hz, H6b′), 3.77
(dd, 1H, J 5,6 ) 7.3 Hz, H6a′), 3.74 (dd, 1H, H5′), 3.71 (m, 2H,
Hz, H5), 3.43 (dq, 1H, J 5,6 ) 6.2 Hz, H5′′), 2.98 (t, 2H, J vic
)
7.7 Hz, CH2N3), 2.17 (ddd, 1H, J gem ) 13.9 Hz, H3eq′′), 2.06 (s,
3H, CH3CONH), 2.20 (s, 3H, CH3CONH), 1.65 (ddd, 1H,
H3ax′′), 1.65 (m, 2H, CH2CH2CH2NH3+), 1.55 (m, 2H, J ) 6.4
Hz, CH2CH2CH2O), 1.40-1.30 (m, 4H, CH2CH2CH2CH2), 1.27
(d, 3H, H6′′). 13C NMR (600 MHz, D2O): δ 17.9 (C6′′), 22.9
(CH3NHCO), 23.0 (CH3NHCO), 25.3, 25.97 (OCH2CH2CH2,
OCH2CH2CH2CH2), 27.41 (CH2CH2NH3), 29.09 (OCH2CH2),
37.3 (C3′′), 52.6 (C2′), 55.8 (C2), 61.9 (C6′), 67.7 (C4′′), 68.5
(C2′′), 68.8 (C4′), 73.5 (C3), 75.38 (C5), 75.9 (C5′), 76.9 (H5′′),
79.8 (C3′), 80.2 (C4), 102.0 (J C1-H1 ) 162.6 Hz, C1, â), 102.2
(J C1-H1 ) 162.3 Hz, C1′, â), 103.4 (J C1-H1 ) 159.4 Hz, C1′′, â).
HR electrospray m/z: calcd for C28H51N3O14Na, 676.3268;
found, 676.3269.
6-(Flu or escein ylth iou r eido)h exyl (3,6-dideoxy-a r a bin o-
h exop yr a n osyl)(1f3)(2-a ceta m id o-2-d eoxy-â-D-ga la cto-
p yr a n osyl)(1f4)-2-a ceta m id o-2-d eoxy-â-D-glu cop yr a n o-
sid e (1). The trisaccharide 33 (10 mg) was dissolved in 1 mL
of DMF/H2O (1:1) containing sodium bicarbonate (20 mg).
Fluorescein isothiocyanate (10 mg) was added, the reaction
mixture was stirred for 1 h, the reaction was quenched with
ethylenediamine (20 µL), and the reaction mixture was
concentrated to a yellow film. This film was taken up in water
and purified by HPLC on C18 reverse-phase silica using a 10-
50% acetonitrile gradient. The fractions were collected and
lyophilized to give 1 (11 mg, 75%). [R]D: -12.7 (c 0.11, H2O).
1H NMR (600 MHz, CD3OD): 8.12 (s, 1H, H4fl), 7.76 (br d,
1H, H6fl), 7.41 (d, 1H, J ) 8.2 Hz, H7fl), 6.67-6.52 (m, 4H,
H2′fl, H5′fl, H7′fl), 4.56 (d, 1H, J 1,2 ) 0.8 Hz, H1′′), 4.51 (d,
1H, J 1,2 ) 8.6 Hz, H1′), 4.35 (d, 1H, J 1,2 ) 8.4 Hz, H1), 4.07
(dd, 1H, J 2,3 ) 10.6 Hz, H2′), 4.02 (d, 1H, J 3,4 ) 3.1 Hz, H4′),
3.88 (dd, J vic ) 6.0 Hz, J gem ) 9.7 Hz, OCH2CH2), 3.80 (dd,
1H, J 5,6a ) 2.0 Hz, J gem ) 12.0 Hz, H6a), 3.78 (br t, 2H, J 2,3ax
≈ J 2,3eq ) 3.4 Hz, H2′′), 3.76 (d, 1H, J gem ) 11.4 Hz, H6a′),
3.75 (dd, J 2,3 ) 9.7 Hz, H3′), 3.72 (dd, 1H, J 2,3 ) 10.3 Hz, H2),
3.67 (dd, 1H, J 5,6 ) 4.4 Hz, H6b′), 3.62 (dd, J 5,6 ) 4.8 Hz, H6b),
H2, H3), 3.67 (dd, 1H, J 5,6 ) 5.5 Hz, H6a), 3.63 (dd, 1H, J 3,4
≈
J 4,5 ) 8.0 Hz, H4), 3.55 (ddd, 1H, J 3ax,4 ) 11.5 Hz, J 3eq,4 ) 4.7
Hz, J 4,5 ) 9.3 Hz, H4′′), 3.53 (ddd, 1H, H5), 3.50 (s, 3H, OMe),
3.44 (dq, 1H, J 5,6 ) 6.2 Hz, H5′′), 2.17 (ddd, 1H, J gem ) 13.9
Hz, H3b′′), 2.06 (s, 3H, CH3NHCO), 2.02 (s, 3H, CH3NHCO),
1.66 (ddd, 1H, H3a′′), 1.27 (d, 3H, H6′′). 13C NMR (600 MHz,
D2O): δ 18.2 (C6′′), 23.1 (CH3NHCO), 23.2 (CH3NHCO), 37.5
(C3′′), 52.4 (C2′), 55.9 (C2), 61.1 (C6′), 61.8 (C6′), 67.8 (C4′′),
68. 5 (C2′′), 68.8 (C4′), 73.7 (C3), 75.6 (C5), 76.0 (C5′), 76.5
(C5′′), 79.9 (C3′), 80.3 (C4), 102.8 (J C1-H1 ) 161.81 Hz, C1, â),
102.2 (J C1-H1 ) 163.18 Hz, C1′, â), 103.5 (J C1-H1 ) 159.76 Hz,
C1′′, â). HR electrospray m/z: calcd for
591.2377; found, 591.2379.
C23H40N2O14Na,
6-Am in oh exyl (3,6-d id eoxy-a r a bin o-h exop yr a n osyl)-
(1f3)(2-a ceta m id o-2-d eoxy-â-D-ga la ctop yr a n osyl)(1f4)-
2-a ceta m id o-2-d eoxy-â-D-glu cop yr a n osid e (33). The pro-
tected trisaccharide 32 (30 mg) was dissolved in 3 mL of
ethylenediamine under argon. Lithium ribbon (10 mg) was
added, and the solution slowly turned deep blue. When the
solution returned to a yellow color, the reaction was quenched
with methanol, and the volatiles were removed under vacuum.
The white solid obtained was dissolved in water, and the
solution was brought to neutral pH by the addition of 5 M
acetic acid, as monitored on pH paper (1-12). The solution
was then applied to a Sep Pak C18 reverse-phase cartridge
(Waters), washed with water, and the crude product was eluted
with 50% methanol. Further purification by HPLC on C18
silica (water + 0.1% TFA/methanol) gave pure 33 (14 mg, 75%
yield) as the trifluoroacetate salt. [R]D: -17.0 (c 0.27, H2O).
1H (600 MHz, D2O): δ 4.70 (d, 1H, J 1,2 < 1 Hz, H1′′), 4.58 (d,
1H, J 1,2 ) 8.4 Hz, H1′), 4.49 (ABX, 1H, J 1,2 ) 8.4 Hz, H1),
4.13 (d, 1H, J 3,4 ) 3.3 Hz, H4′), 4.04 (dd, 1H, J 2,3 ) 10.8 Hz,
3.61-3.57 (m, 4H, H3, H5′, CH2NHCS), 3.52 (dd, J 3,4 ≈ J 4,5
)
9.5 Hz, H4), 3.48 (dd, 1H, J vic ) 2.2 Hz, CH2CH2O), 3.46 (ddd,
J 3eq,4 ) 4.4 Hz, J 3ax,4 ≈ J 4,5 ) 10.9 Hz, H4′′), 3.31 (ddd, 1H,
H5), 3.27 (dq, 1H, J 5,6 ) 6.2 Hz, H5′′), 2.11 (ddd, 1H, J gem
)
13.5 Hz, H3eq′′), 1.97 (s, 3H, CH3CONH), 1.96 (s, 3H, CH3-
CONH), 1.69-1.63 (m, 2H, CH2CH2NHCS), 1.62-1.55 (m, 2H,
CH2CH2CH2O), 1.52 (ddd, 1H, H3ax′′), 1.48-1.37 (m, 4H,
CH2CH2CH2CH2), 1.25 (d, 3H, H6′′). HR electrospray m/z:
calcd for C49H62N4O19SNa, 1065.3626; found, 1065.3627.
Ack n ow led gm en t. The research was made possible
by Natural Science and Engineering Reserch Council
of Canada (NSERC) grants to D.R.B. and a postgradu-
ate scholarship to M.N.
J O991812K