1,6-Anhydro-N-acetyl-β-D-glucosamine in oligosaccharide synthesis: II. The synthesis of the spacered Ley tetrasaccharide

Article abstract of DOI:10.1134/S1068162007010128

3-Aminopropyl glycoside of 3,2'-di-O-α-L-fucosyl-N-acetyllactosamine (Le^y tetrasaccharide) was synthesized. The glycosyl donor, 2-O-acetyl-2,4,6-tri-O-benzoyl-α-D-galactopyranosyl bromide, was coupled with glycosyl acceptor, 1,6-anhydro-2-acetamido-2-deoxy-β-D-glucopyranose or its 3-O-acetyl derivative, to give the corresponding N-acetyllactosamine derivatives in 20 and 71% yields, respectively. The glycosyl donor was synthesized from 1,2-di-O-acetyl-3,4,6-triO-benzoyl-D-galactopyranose, which was obtained by the treatment of benzobromogalactose with sodium borohydride to yield 1,2-O-benzylidene derivative and subsequent removal of benzylidene group and acetylation. Acidic methanolysis of the disaccharide derivatives resulted in the selective removal of one or both acetyl groups to give the disaccharide acceptor bearing hydroxy groups at C3 of the glucosamine residue and C2 of the galactose residue. The introduction of fucose residues in these positions by the treatment with tetrabenzylfucopyranosyl bromide resulted in a tetrasaccharide derivative, which was converted into 3,2'-di-O-α-L-fucopuranosyl-1,6- anhydro-N-acetyllactosamine peracetate after substitution of acetyl groups for benzoyl and benzyl groups. Opening of the anhydro ring by acetolysis resulted in peracetate, which was then converted into the corresponding oxazoline derivative by two steps. Glycosydation of the oxazoline derivative with 3-trifluoroacetamidopropan-1-ol and removal of O-acetyl and N-trifluoroacetyl protective groups resulted in a free spacered Le^y tetrasaccharide.

Full text of DOI:10.1134/S1068162007010128

ISSN 1068-1620, Russian Journal of Bioorganic Chemistry, 2007, Vol. 33, No. 1, pp. 99–109. © Pleiades Publishing, Inc., 2007.
Original Russian Text © N.E. Byramova, A.B. Tuzikov, T.V. Tyrtysh, N.V. Bovin, 2007, published in Bioorganicheskaya Khimiya, 2007, Vol. 33, No. 1, pp. 108–118.
SYNTHETIC
STUDIES
1,6-Anhydro-N-Acetyl-b-D-Glucosamine in Oligosaccharide
Synthesis: II.1 The Synthesis of the Spacered Ley Tetrasaccharide
N. E. Byramova2, A. B. Tuzikov, T. V. Tyrtysh, and N. V. Bovin
Shemyakin–Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences,
ul. Miklukho-Maklaya 16/10, Moscow, 117997 Russia
Received April 03, 2006; in final form, May 11, 2006
Abstract—3-Aminopropyl glycoside of 3,2'-di-O-α-L-fucosyl-N-acetyllactosamine (Ley tetrasaccharide) was
synthesized. The glycosyl donor, 2-O-acetyl-2,4,6-tri-O-benzoyl-α-D-galactopyranosyl bromide, was coupled
with glycosyl acceptor, 1,6-anhydro-2-acetamido-2-deoxy-β-D-glucopyranose or its 3-O-acetyl derivative, to
give the corresponding N-acetyllactosamine derivatives in 20 and 71% yields, respectively. The glycosyl donor
was synthesized from 1,2-di-O-acetyl-3,4,6-triO-benzoyl-D-galactopyranose, which was obtained by the treat-
ment of benzobromogalactose with sodium borohydride to yield 1,2-O-benzylidene derivative and subsequent
removal of benzylidene group and acetylation. Acidic methanolysis of the disaccharide derivatives resulted in
the selective removal of one or both acetyl groups to give the disaccharide acceptor bearing hydroxy groups at
C3 of the glucosamine residue and C2 of the galactose residue. The introduction of fucose residues in these
positions by the treatment with tetrabenzylfucopyranosyl bromide resulted in a tetrasaccharide derivative,
which was converted into 3,2'-di-O-α-L-fucopuranosyl-1,6-anhydro-N-acetyllactosamine peracetate after sub-
stitution of acetyl groups for benzoyl and benzyl groups. Opening of the anhydro ring by acetolysis resulted in
peracetate, which was then converted into the corresponding oxazoline derivative by two steps. Glycosydation
of the oxazoline derivative with 3-trifluoroacetamidopropan-1-ol and removal of O-acetyl and N-trifluoroacetyl
protective groups resulted in a free spacered Ley tetrasaccharide.
Key words: 1,6-anhydro-GlcNAc, glycosylation, oligosaccharides, tumor-associated antigens
DOI: 10.1134/S1068162007010128
INTRODUCTION
and Ley using another strategy, i.e., starting from the
GlcNAc derivative with a spacer group, has also been
carried out [7].
Previously [1], we suggested 1,6-anhydro-GlcNAc
as a synthon for the syntheses of oligosaccharides con-
taining the N-acetyllactosamine unit (LacNAc, Galβ1-
4GlcNAc disaccharide). N-Acetyllactosamine substi-
tuted with the α-L-fucose residue at é2 of the galactose
moiety is a constituent of group-specific H (type 2)
antigen; N-acetyllactosamine bearing the α-L-fucose
residue in O3 of the GlcNAc moiety is a constituent of
Lex antigen, and, finally, N-acetyllactosamine substi-
tuted with two α-L-fucose residues in both é2 of Gal
and O3 of GlcNAc is a part of Ley antigen (see
Scheme 1) [2, 3].
The following strategy for the synthesis is suggested
[8, 9]. First, the lactosamine core (I) disaccharide bear-
ing only acetyl and benzoyl protective groups in the
corresponding positions is built up, and the hydroxy
group at the reducing end is blocked by including into
the 1,6-anhydro ring [(Ib), (Ic), and (Id)] (Scheme 2).
The core (I) is constructed by condensation of glycosyl
donor (II) with the corresponding acceptor (IIIa)–
Galβ1-4GlcNAc
A number of communications report the synthesis
of H (type 2), Lex, and Ley oligosaccharides [4]. For
example, a synthesis of Ley 2(4-nitrophenyl)ethyl gly-
coside is described in [5] (see also communications
cited therein). A synthesis of Ley from the derivative of
galactose glycal is reported in [6]. In our laboratory,
synthesis of 3-aminopropyl glycosides of H (type 2)
Galβ1-4GlcNAc Galβ1-4GlcNAc Galβ1-4GlcNAc
3
2
2
3
Fucα1
Fucα1 Fucα1
Fucα1
H (type 1)
Ley
Lex
1
For Part I, see [1].
Corresponding author, phone: +7 (495) 330-7492; e-mail:
2
Scheme 1.
tuzikov@carb.ibch.ru.
99

100
BYRAMOVA et al.
O
OBz
O
BzO
OR
O
OR
O
OBz
O
BzO
BzO
O
BzO
O
NHAc
AcO
HO
NHAc
Br
R'O
(I‡–Â)
(II)
(III‡–c)
(I‡) R = R' = H
(Ib) R = R' = Ac
(Ic) R = H, R' = Ac
(Id) R = Ac, R' = H
(Ie) R = Bz, R' = Ac
(If) R = Ac, R' = Bz
(III‡) R = H
(IIIb) R = Bz
(IIIc) R = Ac
Br
O
H3C
OBn
OBn
BnO
(IV)
Scheme 2.
OBz
O
BzO
BzO
OBz
O
BzO
BzO
OBz
O
BzO
BzO
(II)
O
O
BzO
OR
RO
(VII) R = H
(II‡) R = Ac
Br
Ph
(VI)
(V)
Scheme 3.
(IIIc), a derivative of 1,6-anhydro-GlcNAc. A mild kov et al. [16, 17] for the synthesis of the L-rhamnose
acidic methanolysis [10] of the key disaccharide (I), derivative with similar protective groups.
which allows the selective removal of acetyl groups in
Benzobromogalactose (V) was converted into
the presence of benzoyl groups, results in deprotection
tribenzoate of 1,2-é-benzylidene derivative (VI) as a
of the hydroxy groups in the positions to be fucosy-
mixture of R- and S-isomers by the treatment with
lated. Mono- or bisfucosylation in these positions with
sodium borohydride in acetonitrile in the presence of
donor (IV) results in the target oligosaccharides. The
tetrabutylammonium iodide according to the method
next step includes deprotection of the reducing end by
[18] (see Scheme 3). The removal of the benzylidene
opening of the 1,6-anhydro ring and subsequent treat-
protective group with trifluoroacetic acid resulted in
ment with the spacer alcohol.
diol (VII), which was then acetylated to diacetate (II‡),
We herein report the synthesis of protected Ley tet- the precursor of bromide (II). Diacetate (IIa) can be
rasaccharide (XVII) and its transformation to free ami- synthesized according to the scheme (V)
(VI)
nopropyl glycoside (XVIII) convenient for further (VII)
(II‡) without purification of intermediates
modifications at the amino group. Neoglycoconjugates [except for diol(VII)] and results in diacetate (II‡) in a
obtained on the basis of tetrasaccharide (XVIII) high yield from the starting bromide (V).
according to the method [11], have been used in a num-
In the original variant of core (I) synthesis, diol
ber of biological studies [12–15], in particular, for
(III‡) [1] was used as acceptor to provide the shortest
obtaining monoclonal antibodies to Ley antigen [12].
route to Ley tetrasaccharide. The reaction of acceptor
(III‡) with donor (II) in acetonitrile or in acetonitrile–
dichloromethane in the presence of mercury cyanide–
RESULTS AND DISCUSSION
mercury bromide resulted in disaccharide (Ic) in
The substituted galactose donor, 2-é-acetyl-3,4,6- approximately 3% yield. The use of nitromethane–ben-
tri-é-benzoyl-α-D-galactopyranosyl bromide (II) also zene as a solvent at room temperature allowed an
necessary for obtaining of the H (type 2) trisaccharide increase in the yield up to 10%. The proceeding of the
was synthesized starting from bezobromogalactose (V) reaction in refluxing nitromethane–benzene appeared
according to a tree-step scheme. This scheme method- to be the best variant of condensation conditions. The
ologically coincides with the scheme used by Kochet- yield of the target β-(1–4)disaccharide (Ic) was 20%.
RUSSIAN JOURNAL OF BIOORGANIC CHEMISTRY Vol. 33 No. 1 2007

1,6-ANHYDRO-N-ACETYL-β-D-GLUCOSAMINE
101
OBz
O
RO
BzO
BzO
OR
O
OR
O
H3C
OR'
O
O
(VIII)
O
O
β(1–3) 7%
O
AcO
O
R'O
R'O
HO
NHAc
O
O
(I‡) + (IV)
NHAc
OH
O
O
OBz
(IX)
α(1–4) ~1.4%
O
O
H3C
OR
BzO
O
NHAc
OR
AcO
RO
BzO
(X) R = Bn, R' = Bz
(XI) R = Bn, R' = H
(XII) R = R' = H
Scheme 4.
(XIII) R = R' = Ac
Glycosylation in the O4 position was evident from the
Scheme 5.
Overhauser effect in the 1H NMR spectra.
To complete the confirmation of the formation of the
β-(1–4) linkage, the resulting derivative (Ic) was trans-
formed to acetate (Ib). The signal of H3 of the GlcNAc
residue, which appeared as a broadened singlet at
resulted in a decrease in the diol (Ia) yield to 40%, but
allowed us to isolate disaccharide (Ic), the product of
deacetylation at é3 of the glucosamine residue, in 31%
yield. Moreover, disaccharide (Id), the product of
deacetylation at é2 of the galactose residue (8%), and
the starting diacetate (Ib) (4%) were also isolated.
1
δ 3.894 ppm in the H NMR spectrum of the starting
hydroxy derivative (Ic), underwent the characteristic
downfield shift to δ 4.995 in the case of 3-é-acetylated
1
derivative (Ib). The H NMR spectrum of (Ib) totally
The results demonstrate that the acetyl group at O2
of the β-galactopyranose residue of diacetate (Ib) is
more stable than that at O3 of the glucosamine residue
under the conditions of acidic methanolysis. This cor-
relates well with the literature data on the increased sta-
coincided with that of the disaccharide obtained by
condensation of bromide (II) with acceptor (IIc), 3-O-
acetyl derivative of 1,6-anhydro-GlcNAc, reported in
the previous communication [1].
Along with the target β-(1–4)-disaccharide (Ic), we bility of acetyl group at O2 of galactose β-glycoside
have also isolated from the mixture of diol (IIIa) galac- under the conditions of the Zemplen deacetylation [19].
tosylation products (VIII) and (IX) in 7 and 1.4% yield, Thus, a selective deacetylation of diacetate (Ib) enables
respectively (Scheme 4), which were identified as β-(1–3) the preparation of all the core disaccharide acceptors
and α-(1–4) isomers by 1H NMR spectra.
required for the syntheses of the corresponding oli-
gosaccharides Ley, Lex, and H (type 2).
Further, we carried out the condensation of donor
(II) with 4-hydroxy derivative (IIIc) as the acceptor.
Glycosylation under the conditions of the Helferich
reaction proceeded as expected with a high efficiency
and resulted in disaccharide derivative (Ib) in 71%
yield; it was identical to that obtained from disaccha-
ride (Ic) by acetylation.
Disaccharides (Ic) and (Ib) were subjected to selec-
tive acidic deacetylation [10]. We succeeded in conver-
sion of derivative (Ic) bearing the only hydroxyl group
at é2 of the galactose residue to the target diol (I‡) in
52% yield and returned 19% of the starting (Ic). An
increase in the reaction time (more than 24 h at room
temperature) raised the conversion of the starting (Ic),
but resulted in appearance of side products.
The resulting diol (I‡) was condensed with fucosyl
bromide (IV) [20] by the Lemieux method [21, 22]
(Scheme 5). The product (X) was debenzoylated by
sodium methylate in methanol to give triol (XI), which
was isolated in 57% yield by column chromatography
[from starting diol (I‡) in two steps].The 1H NMR spec-
trum of (XI) exhibited two doublets at δ 1.347 and
1.388 ppm with a coupling constant of 6.5 Hz corre-
sponding to H6 atoms of fucose residues. The α-config-
uration of the fucose residues was confirmed by the
presence of two doublets at δ 5.346 and 5.414 ppm with
J 3.6 and 3.1 Hz, respectively (see the Experimental
section).
The catalytic hydrogenolysis of benzyl groups in
Deacetylation of disaccharide derivative (Ib) under (XI) over Pd/C resulted in the free tetrasaccharide (XII)
the same conditions proceeded with the same effective- in 96% yield. Acetylation of (XII) with the acetic anhy-
ness and resulted in diol (Ia) (55%) and starting diace- dride in pyridine resulted in the peracetate of 1,6-anhy-
tate (Ib) recovered (20%, data not shown in the Exper- dro derivative of Ley tetrasaccharide (XIII) in 94%
imental section). Milder reaction conditions due to yield. The derivative (XIII) was acetolyzed by acetic
increase in the chloroform content in reaction mixture anhydride in acetic acid in the presence of concentrated
RUSSIAN JOURNAL OF BIOORGANIC CHEMISTRY Vol. 33 No. 1 2007

102
BYRAMOVA et al.
O
O
O
N
(XIII)
OH
OAc
AcNH
(XV)
AcNH
(XIV)
O
(XVI)
CH3
HO
OH
O
OH
H C
3
OH
O
O
O(CH ) NHCOCF
2 3
HO
O
O
O
O
O(CH ) NH
AcNH
2 3
2
HO OH
AcNH
O
(XVIII)
(XVII)
H C
3
OH
OH
HO
Scheme 6.
H2SO4 to open the 1,6-anhydro ring. Substitution of tri- DMF by the method [25] to give monohydroxy deriva-
fluoroacetic acid for sulfuric acid did not result in open- tive (XV) as a mixture of anomers in 80% yield. The
ing of the 1,6-anhydro ring. It should be noted that free mixture of anomers (XV) was converted into oxazoline
tetrasaccharide (XII) can also be subjected to acetoly- (XVI) with mesyl chloride in the presence of collidine
sis, as it reacts similarly to its acetate (XIII). The [26]. The resulting oxazoline (XVI) was homogenous
attempt to acetolyze derivative (XI) with benzylated according to TLC data and was used at the next step
fucose residues resulted in almost complete cleavage of without additional purification. The reaction of oxazo-
fucoside bond. Similar examples of the fucoside bond line (XVI) with spacered alcohol in toluene in the pres-
ence of anhydrous TsOH as described in [26] resulted
lability in perbensylated fucose were reported in [23,
24]. Therefore, the removal of benzyl groups before
acetolysis is necessary in our case. After 17-h acetoly-
sis, the starting anhydride (XIII) completely reacted
and the reaction mixture contained peracetate (XIV) as
a mixture of anomers with different Rf values and
oxazoline (XVI) (Scheme 6). As the content of oxazo-
line (XVI) did not exceed 60% (visually, TLC), it was
hydrolyzed to anomeric 1-OH derivatives (XV), which
differed in Rf (TLC) like acetates. The resulting mixture
of acetates (XIV) and 1-OH derivatives (XV) was
treated with acetic anhydride in pyridine, to transform
derivatives (XV) to the corresponding acetates (XIV).
The mixture of anomers (XIV) was obtained in 89%
yield, with the α-anomer of the less chromatographic
in the target protected glycoside (XVII) in 81% yield.
1
The signal of H1 of the GlcNAc unit in the H NMR
spectrum of glycoside (XVII) was shifted upfield
(5.95
4.63 ppm) as compared to that in the spec-
trum of the starting α-anomer of acetate (XIV) because
of the substitution of the O-alkyl residue for the O-acyl
unit. The value of the coupling constant that character-
ized the α-configuration (3.9 Hz) changed for 8.3 Hz,
which corresponds to the β-configuration.
The removal of é- and N-protective groups in
(XVII) in the presence of ion-exchange resin (OH-) by
the method [11] resulted in free aminopropyl glycoside
(XVII). The structure of (XVIII) was confirmed by 1ç-
and 13C NMR spectra (see the Experimental section).
1
mobility prevailing. A comparison of the H NMR
spectrum of the starting anhydro derivative (XIII) and
the resulting peracetate (XIV) confirmed the transfor-
EXPERIMENTAL
4
mation of the ë1 unit of GlcNAc to the relaxed ë1
4
1
The H NMR spectra [1D, the values of chemical
conformation with axial H2–H5. The signals of H1, H2,
H6a, and H6b were significantly (by 0.35–0.74 ppm)
shifted downfield. The coupling constants for H2–H5
from approximately 1 Hz in (XIII) rose up to 8–10 Hz
for (XIV), which is characteristic of trans-diaxial pro-
tons.
shifts (δ ppm) relative to Me4Si and the values of cou-
13
pling constants (J, Hz) are given) and C NMR (at a
working frequency of 67.5 MHz, δ, ppm) of CDCl3
solutions were registered on WM-500 and WM-250
Bruker spectrometers. The values of optical rotation
were measured on a Jasco DIP-360 polarimeter at
The transformation of (XIV) to the target spacered 20°ë. LC was carried out on silica gel 60 (Merck,
tetrasaccharide (XVIII) was achieved according to 5553). TLC was carried out on precoated silica gel 60
Scheme 6. The mixture of anomeric acetates (XIV) was (Merck) glass plates or aluminum sheets using the fol-
selectively de-1-é-acetylated by hydrazine acetate in lowing developing systems: chloroform–methanol–
RUSSIAN JOURNAL OF BIOORGANIC CHEMISTRY Vol. 33 No. 1 2007

1,6-ANHYDRO-N-ACETYL-β-D-GLUCOSAMINE
103
hexane, hexane–chloroform–isopropanol, toluene–ace- br. s, 1-OH), 7.40–7.770 (m, Ar), 7.85 (m, Ar), 6.0–6.25
tone, ethyl acetate–toluene, and isopropanol–ethyl ace- (m, Ar); β-anomer: 4.12 [1 H, ddd (m), H5], 4.38 (1 H,
tate–water. Carbohydrates were visualized by heating dd, J6a,6b 11, J6a,5 2–3, H6a), 4.63 (1 H, dd, J6b,6a 11.5,
the plates after the treatment with 7% orthophosphoric
acid; carbohydrates with the free amino group were
visualized by soaking in a ninhydrin solution and sub-
sequent heating. The solutions were dried by filtration
through a cotton layer. Molecular sieves 4Å (Fluka)
were dried at 300°ë for 3 h. Tribenzylfucosyl bromide
(IV) [20] was obtained from the corresponding thiogly-
coside as described in [27]. 2,3,4,6-Tetra-é-benzoyl-α-
D-galactopyranosyl bromide (V) was prepared from
penta-é-benzoyl-β-D-galactopyranose [28] by the pro-
cedure [16, 17].
J
6b,5 6, H6b), 5.40 (1 H, dd, J3,2 10, J3,4 4, H3), 5.93 (1
H, dd, J4,5 1–1.5, J4,3 3.5, H4), 2.40 (1 H, br. d, JOH,1 5,
2-OH), 3.28 (1 H, br. s, 1-OH), 7.40–7.770 (m), 7.85
(m), 6.0–6.25 (m, Ar).
1,2-Di-é-acetyl-3,4,6-tri-é-benzoyl-a,b-D-
galactopyranose (IIa). Diol ((VII), 8.40 g) was acety-
lated with ÄÒ2é (20 ml) in pyridine (40 ml) (48 h,
20°ë). The reaction mixture was carefully decomposed
with water (5 ml) at cooling with ice. After 40 min, the
solution was diluted with CHCl3 (400 ml); washed with
water, saturated NaHCO3, water, and 1 N HCl; filtered
through a cotton layer; and concentrated to give 9.8 g
(100%) of diacetate (II‡) as a mixture of anomers
(α/β ~ 3/2); 1H NMR, α-anomer: 2.12 and 2.38 (3 H, 2
s, 2 Ac), 4.512 (1 H, dd, J6a,5 6.7, J6a,6b 11, H6a), 4.740
(1 H, dd, J6b,5 6, H6b), 4.845 [1 H, dd (t), H5], 5.855 (1
1,2-é-Benzylidene-3,4,6-tri-é-benzoyl-a-D-
galactopyranose (VI). Tetrabutylammonium iodide
(3.99 g, 10.8 mmol) was added to a mixture of benzoyl-
bromogalactose (V) (13 g, 19.7 mmol), anhydrous ace-
tonitrile (50 ml) and sodium borohydride (1.06 g,
28 mmol); the mixture was stirred at room temperature
for 48 h and then quenched carefully with an acetic acid
solution (2.2 ml in 15 ml of water) at stirring. The trans-
parent solution was diluted with chloroform (250 ml)
and washed with water (3 × 200 ml). The chloroform
solution was concentrated in a vacuum to give the mix-
ture of S- and R-isomers (in 9 : 5 ratio according to the
1H NMR) [18] of benzylidene derivative (VI) as a
syrup, which was used in the next step without purifica-
tion; 1H NMR, S-isomer: 4.378 (1 H, dd, J6‡,6b 12, J6a,5
6, H6a), 4.477 (1 H, dd, J2,1 = J2,3 5, H2), 5.60 (1 H, dd,
J3,2 6, J3,4 4, H3), 5.858 (1 H, dd, J4,3 = J4,5 3.5–4.0, H4),
4.57–4.61 (in m, H5), 5.916 (d, J2,1 5, H1), 5.988 (1 H,
s, CHPh), 7.5 (m, Ar), 8.0 (m, Ar); R-isomer: 4.312 (1
H, dd, J6a,6b 14, J6a,5 6, H6), 4.57–4.61 (in m, H2, H5),
5.66 (1 H, dd, J3,2 7, J3,4 3.5, H3), 5.962 (1 H, m, J1,2 4,
H4), 6.34 (1 H, s, CHPh), 7.5 (m, Ar), 8.0 (m, Ar).
H, dd, J2,1 3.5, J2,3 11, H2), 6.215 (1 H, dd, J4,3 3, J4,5
≤
1, H4), 5.938 (1 H, dd, H3), 6.725 (1 H, d, H1), 7.50–
8.20 (m, Ar); β-anomer: 2.13 and 2.35 (3 H, 2 s, 2 Ac),
4.565 (1 H, dd, J6a,5 6.7, J6a,6b 11, H6a), 4.70 (m, H6b),
4.845 [1 H, dd (t), J5,4 ≈ 1, J5,6a ≈ J5,6b 5.5–6.0, H5],
5.646 (1 H, dd, J3,2 10.5, J3,4 3.5, H3), 5.818 (1 H, dd,
J2,1 8, H2), 6.08 (1 H, d, H1), 6.138 (1 H, dd, H4), 7.50–
8.20 (m, Ar).
2-é-Acetyl-3,4,6-tri-é-benzoyl-a-D-galactopyr-
anosyl bromide (II). A solution of (IIa) (4.05 g,
7.02 mmol) was dissolved in a mixture of chloroform
(40 ml) and AcOH (20 ml) and cooled to 0°ë; AcBr
(9 ml, 122 mmol) and then a solution of water (1.26 ml,
70 mmol) in AcOH (5 ml) were added. Cooling was
removed, and the reaction mixture was kept for 3 h at
room temperature, monitoring the process with TLC
(1 : 9 ethyl acetate–toluene) for the starting acetate,
Rf 0.47, and for the bromide, Rf 0.71. The reaction mix-
ture was poured on ice and diluted with chloroform.
The organic layer was twice washed with saturated
NaHCO3, dried, and evaporated to dryness to give
4.18 g (quantitative) of chromatographically individual
bromide (II) as light-yellow foam, which was immedi-
ately used in the synthesis of (Ic); 1H NMR: 2.07 (3 H,
s, An), 4.44 (1 H, dd, J6a,5 6, J6a,6b 11.5, H6a), 4.61 (1 H,
dd, J6b,5 6.8, H6b), 4.86 (1 H, ddd, J5.4 ≤1, H5), 5.42
(1 H, dd, J2,1 4, J2,3 10.5, H2), 5.86 (1 H, dd, J3,4 3.3,
H3), 6.07 (1 H, dd, H4), 6.87 (1 H, d, H1), 8.08–7.32
(m, Ar).
3,4,6-Tri-é-benzoyl-a,b-D-galactopyranose VII.
The product (VI) was dissolved in chloroform (75 ml),
a mixture of TFA (40 ml) and water (2 ml) was added,
and the mixture was kept for 2 h until the complete dis-
appearance of the starting compound (VI) [(Rf 0.80,
2 : 8 ethyl acetate–toluene) and Rf 1.00 (9 : 1 : 1 chloro-
form–methanol–hexane)] and formation of diol (VII)
(Rf 0.00 (2 : 8 ethyl acetate–toluene) and 0.51 and 0.49
(the mixture of α- and β-anomers, 9 : 1 : 1 chloroform–
methanol–hexane)]. The solution was washed with
water (2 × 150 ml), saturated Na2CO3 (4 × 200 ml), fil-
tered through a cotton layer, and concentrated. The res-
idue was chromatographed in a gradient of methanol
1,6-Anhydro-2-acetamido-4-é-(2-é-acetyl-3,4,6-
tri-é-benzoyl-b-D-galactopyranosyl)-2-deoxy-b-D-
glucopyranose (Ic). Diol (IIIa) (1.42 g, 7 mmol), mer-
cury cyanide (1.77 g, 7 mmol), mercury bromide
(0.25 g, 0.7 mmol), and powdered molecular sieves
4Å(5 g) were stirred in a mixture of nitromethane
(50 ml) and anhydrous benzene (5 ml) at room temper-
ature for 2 h. The mixture was heated at a moderate
reflux (~80°ë) and a solution of bromide (II) [obtained
from 7.02 mmol of diacetate (II‡)] in anhydrous ben-
0
3) in chloroform to give diol (VII) (a mixture of
anomers) as white foam; yield 8.46 g (87% from the
bromide); [α]2D0 +50.5° (c 0.93; chloroform); 1H NMR,
α-anomer: 4.32 [1 H, ddd (m), J2,1 3, H5], 4.36 (1 H, dd,
J6a,6b 11, J6a,5 6, H6a), 4.59 (1 H, dd, J6b,6a 11, J6b,5 7,
H6b), 5.58 [1 H, dd (t), J1,2 = J1,OH 3–3.5, H1], 5.66 (1
H, dd, J3,2 10, J3,4 3–3.5, H3), 5.96 (1 H, dd, J4,5 1–1.5,
J4,3 3.5, H4), 2.40 (1 H, br. d, JOH,1 5, 2-OH), 3.28 (1 H,
RUSSIAN JOURNAL OF BIOORGANIC CHEMISTRY Vol. 33 No. 1 2007

104
BYRAMOVA et al.
zene (30 ml) was added for 0.5 h at a vigorous stirring.
The resulting mixture was heated for another 2 h and
kept for 16 h at room temperature. The mixture was fil-
tered; the sieves were washed with chloroform (2 ×
10 ml) and 1 : 1 chloroform–methanol (2 × 10 ml); the
combined filtrate and organic washings were concen-
trated; and the residue was dissolved in chloroform
(200 ml). The organic layer was washed with water (2 ×
75 ml), 1 N sodium iodide (75 ml), and water (100 ml);
dried; and evaporated to dryness to give 4.64 g of the
residue, which was chromatographed in a gradient of
1,6-anhydro-2-acetamido-4-é-(2-é-acetyl-3,4,6-
tri-é-benzoyl-a-D-galactopyranosyl)-2-deoxy-b-D-
glucopyranose (IX): 73 mg (1.4%); Rf 0.52 (hexane–
chloroform–isopropanol 4 : 2 : 1); 1H NMR: 1.974 and
2.068 (2 × 3 H, s, 2OAc), 3.487 (1 H, dd, J6a,6b 7.4, J6a,5
5.7, H6a, GlcNAc), 3.681 [1 H, dd (br. s), H3, GlcNAc],
3.888 [1 H, dd (br. s), H4, GlcNAc], 4.056 [1 H, ddd (br.
d), J2,HN 9.4, H2, GlcNAc], 5.400 [1 H, d (br. s), H1,
GlcNAc], 5.423 (1 H, d, J1,2 3.6, H1, Gal), 5.523 (1 H,
dd, J2,3 10.8, H2, Gal), 5.810 (1 H, dd, J3,4 3.3, H3, Gal),
5.942 (1 H, dd (br. d), H4, Gal), 6.329 (1 H, d, NH,
GlcNAc);
methanol (0
2%) in chloroform. Fractions contain-
ing disaccharide (Ic) (Rf 0.45, 9 : 1 : 1 chloroform–
methanol–hexane) were combined, concentrated and
dried to give 1.78 g of the product containing the
admixtures of three more compounds (obviously ste-
reo- and regioisomeric disaccharides). The resulting
mixture was additionally fractured by LC on silica gel
1,6-Anhydro-2-acetamido-3-é-acetyl-4-é-(2-é-
acetyl-3,4,6-tri-é-benzoyl-b-D-galactopyranosyl)-
2-deoxy-b-D-glucopyranose (Ib). (A) Mercury cya-
nide (835 mg, 3.3 mmol) and mercury bromide
(119 mg, 0.33 mmol) were added to a solution of
acceptor (IIIc) (540 mg, 2.2 mmol) in a mixture of
anhydrous nitromethane (7 ml) and anhydrous ben-
zene; the mixture was stirred with freshly calcined
molecular sieves 4Å(3 g) for 3 h. A solution of bromide
(II) [prepared from 1.9 g (3.3 mmol) of diacetate (II‡)
in anhydrous benzene (10 ml)] was added to the reac-
tion mixture together with molecular sieves 4Å (2 g).
The mixture was stirred at room temperature for 16 h.
Then, mercury cyanide (279 mg, 1.1 mmol), mercury
bromide (40 mg, 0.1 mmol), and bromide (II)
(1.1 mmol) were added. The mixture was stirred at
room temperature for 16 h, diluted with chloroform,
and filtered off; the sieves were washed with chloro-
form on filter; and the filtrate was concentrated. The
residue was dissolved in chloroform (30 ml); washed
with 2 N sodium iodide, water, saturated NaHCO3, and
water; filtered through a cotton layer; and concentrated.
The residue was chromatographed on silica gel (30 g)
(100 g) in a gradient of isopropanol (0
12%) in
2 : 1 hexane–chloroform; yield 1.02 g (20%) of pure
disaccharide (Ic); Rf 0.45 (4 : 2 : 1 hexane–chloroform–
isopropanol). [α]2D0 –24° (c 1, chloroform); H NMR:
1
2.040 and 2.085 (2 × 3 H, 2 s, NAc, OAc), 3.659 (1 H,
br. s, II, GlcNAc), 3.735 [1 H, dd (br. s), J4,3 ≤ 1, J4,5 ≤ 1,
H4, GlcNAc], 3.765 (1 H, dd, J6a,6b7.2, J6a,5 5.5, H6a,
GlcNAc), 3.894 [1 H, dd (br. s), J3,2 ≤ 1, H3, GlcNAc],
4.175 [1 H, ddd (br. d), J2, NH 10, J2,1 ≤ 1, H2, GlcNAc],
4.247 [1 H, ddd (br. t), J5,4 ≤ 1, J5,6a 6.2, J5,6b 6.6, H5,
Gal], 4.297 [1 H, dd (d), J6b,5 ≤ 1, H6b, GlcNAc], 4.375
(1 H, dd, J6a,6b 11.5, H6a, Gal), 4.528 [1 H, ddd (br. d),
H5, GlcNAc], 4.613 (1 H, dd, H6b, Gal), 4.742 (1 H, d,
J1,2 7.2, H1, Gal), 5.341 [1 H, d (br. s), H1, GlcNAc],
5.467 (1 H, dd, J2,3 10.2, H2, Gal), 5.504 (1 H, dd, J3,4
~ 3, H3, Gal), 5.932 [1 H, dd (d), H4, Gal], 6.348 (1 H,
d, NH), 7.286, 7.393, and 7.458 [3 × 2 H, ttt, m-H(Bz)],
7.479, 7.524, and 7.545 [3 × 1 H, ttt, para-H(Bz)],
7.802, 7.971, and 8.033 [3 × 2 ç, ddd, o-H(Bz)].
in a gradient of isopropanol (0
3%) in 2 : 1 hexane–
chloroform to give 1.192 g (71%) of disaccharide (Ib);
[α]2D0 –24° (c 1, chloroform); H NMR: 1.991, 2.012,
1
We have also isolated
and 2.068 (3 × 3 H, 3 s, NAc, 2 OAc), 3.735 [1 H, dd
(br. s), J4.3 ≤ 1, J4.5 ≤ 1, H4, GlcNAc], 3.792 (1 H, dd,
J6a,6b 7.5, J6a,5 5.5, H6a, GlcNAc), 4.059 [1 H, dd (d),
J6b,5 ≤ 1, H6b, GlcNAc], 4.073 [1 H, ddd (br. d), J2,NH
10, J2.1 ≤ 1, J2,3 ≤ 1, H2, GlcNAc], 4.266 [1 H, ddd (t),
J5,4 ≤ 1, J5,6 = J5,6b 7, H5, Gal], 4.401 (1 H, dd, J6a,6b 11.5,
H6a, Gal), 4.517 [1 H, ddd (br. d), H5-GlcNAc], 4.576
(1 H, dd, H6b, Gal), 4.800 (1 H, d, J1,2 7.3, H1, Gal),
4.995 [1 H, dd (br. s), H3-GlcNAc], 5.322 [1 H, d (br.
s), H1-GlcNAc], 5.463 (1 H, dd, J3,2 10.2, J3,4 ~ 3, H3,
Gal), 5.509 (1 H, dd, H2, Gal), 5.916 [1 H, dd (d), H4,
Gal], 6.288 (1 H, d, NH-GlcNAc), 7.289, 7.387, and
7.479 [3 × 2 H, ttt, metha-H(Bz)], 7.480, 7.520, and
7.611 [3 × 1 H, ttt, para-H(Bz)], 7.805, 7.958, and
8.049 [3 × 2 H, ddd, o-H(Bz)].
1,6-anhydro-2-acetamido-3-é-(2-é-acetyl-3,4,6-
tri-é-benzoyl-b-D-galactopyranosyl)-2-deoxy-b-D-
glucopyranose (VIII): 360 mg (7%), Rf 0.36 (4 : 2 : 1
hexane–chloroform–isopropanol); 1H NMR: 1.960 and
2.039 (2 × 3 H, s, 2OAc), 2.892 [1 H, dd (br. s), H4,
GlcNAc]; 3.707 (1 H, dd, J6a,6b 7.4, J6a,5 6.1, H6a,
GlcNAc), 3.774 [1 H, dd (br. s), H3, GlcNAc], 3.902
[1 H, dd (br. s), H4, GlcNAc], 3.971 [1 H, ddd (br. d),
J
2,HN, 9.4, H2, Gal], 4.131 [1 H, dd (br. d), I6b,
GlcNAc], 4.323 [1 H, ddd (dd), J5,6a 6.5, J5,6b 6.2, H5,
Gal]; 4.371 (1 H, dd, J6a,6b 11, H6a, Gal), 4.516 [1 H,
ddd (br. d), H5, GlcNAc], 4.645 (1 H, dd, H6b, Gal);
5.005 (1 H, d, J1,2 7.9, Gal), 5.353 [1 H, d (br. s), H1,
GlcNAc], 5.517 (2 H, m, H2, H3, Gal); 5.960 [1 H, dd
(br. d), J4,3 < 1.5, H4, Gal], 6.240 (1 H, d, NH, GlcNAc),
7.305, 7.409, and 7.466 [3 × 2 H, ddd, Jm,o 8, Jm,p 7.7,
metha-H(Bz)], 7.490, 7.545, and 7.605 [3 × 1 H, ttt,
para-H(Bz)], 7.833, 7.994, and 8.048 [3 × 2 H, ddd,
ortho-H(Bz)];
(B) Acetylation of monohydroxy derivative (Ic)
with acetic anhydride in pyridine resulted in (Ib) in
1
quantitative yield. According to the H NMR, the
RUSSIAN JOURNAL OF BIOORGANIC CHEMISTRY Vol. 33 No. 1 2007

1,6-ANHYDRO-N-ACETYL-β-D-GLUCOSAMINE
105
(9 : 1 : 6 chloroform–methanol–hexane); [α]2D0 –24°
resulting compound was identical to diacetate (Ib)
obtained as described above.
(c 1, chloroform); 1H NMR: 2.040 and 2.085 (2 × 3 H,
2 s, NAc, OAc), 3.659 (1 H, br. s, OH, GlcNAc), 3.735
[1 H, dd (br. s), J4,3 ≤ 1, J4,5 ≤ 1, H4, GlcNAc], 3.765
(1 H, dd, J6a,6b7.2, J6a,5 5.5, H6a, GlcNAc), 3.894 [1 H,
dd (br. s), J3,2 ≤ 1, H3, GlcNAc], 4.175 [1 H, ddd (br. d),
1,6-Anhydro-2-acetamido-4-é-(3,4,6-tri-é-ben-
zoyl-b-D-galactopyranosyl)-2-deoxy-b-D-glucopyr-
anose (Ia). (A) By deacetylation of monoacetate (Ic).
A solution of HCl in methanol prepared by a dropwise
addition of acetyl chloride (0.5 ml, 7 mmol) to metha-
nol (8 ml) at 0°ë was added to a solution of monoace-
tate (Ic) (1.02 g, 1.417 mmol) in chloroform (2 ml). The
mixture was kept at room temperature for 24 h, diluted
with chloroform, and washed with saturated NaHCO3.
The aqueous washings were extracted with chloroform.
The combined organic extracts were washed with
water, dried, and concentrated. The residue (980 mg)
was subjected to column chromatography in a gradient
J
2,NH 10, J2.1 ≤ 1, H2, GlcNAc], 4.247 [1 H, ddd (br. t),
J5,4 ≤ 1, J5,6a 6.2, J5,6b 6.6, H5, Gal], 4.297 [1 H, dd (d),
J6b,5 ≤ 1, H6b, GlcNAc], 4.375 (1 H, dd, J6a,6b 11.5, H6a,
Gal), 4.528 [1 H, ddd (br. d), H5, GlcNAc), 4.613 (1 H,
dd, H6b, Gal], 4.742 (1 H, d, J1,2 7.2, H1, Gal), 5.341
[1 H, d (br. s), H1, GlcNAc], 5.467 (1 H, dd, J2,3 10.2,
I2, Gal), 5.504 (1 H, dd, J3,4 ~ 3, H3, Gal), 5.932 [1 H,
dd (d), H4, Gal], 6.348 (1 H, d, NH, GlcNAc), 7.286,
7.393, and 7.458 [3 × 2 H, ttt, m-H(Bz)], 7.479, 7.524,
and 7.545 [3 × 1 H, ttt, p-H(Bz)], 7.802, 7.971, and
8.033 [3 × 2 H, ddd, o-H(Bz)];
of isopropanol (4
15%) in 2 : 1 hexane–chloro-
form; yields: 500 mg (52%) of diol (I‡), Rf 0.25 (4 : 2 : 1
hexane–chloroform–isopropanol); [α]2D0 –14.9° (c 1,
chloroform) and 190 mg (19%) of the starting (Ic), Rf
1,6-anhydro-2-acetamido-4-é-(3,4,6-tri-é-ben-
zoyl-b-D-galactopyranosyl)-3-é-acetyl-2-deoxy-b-
D-glucopyranose (Id); yield 77 mg (8%), Rf 0.28 (9 :
1
0.49 (4 : 2 : 1 hexane–chloroform–isopropanol). H
NMR of (Ia): 1.905 (3 H, s, NAc), 3.522 (1 H, br. s,
OH), 3.650 (1 H, dd, J6a,6b7.5, J6a,5 5.5, H6a, GlcNAc); 1 : 6 chloroform–methanol–hexane), [α]2D0 –15.5° (c,
chloroform); 1H NMR: 1.936 and 2.016 (2 × 3 H, 2 s,
NAc, OAc), 3.766 [1 H, dd (br. s), J4,3 ≤ 1, J4,5 ≤ 1, H4,
GlcNAc], 3.766 (1 H, dd, J6a,6b7.8, J6a,5 5.3, H6a,
GlcNAc), 4.010 [1 H, ddd (br. d), J2,NH 8.8, J2,1 ≤ 1,
J2,3 ≤ 1, I2, GlcNAc], 4.010 [1 H, dd (d), J6b,5 ≤ 1, H6b,
GlcNAc), 4.200 (1 H, dd, J2,1 7.8, J2,3 10, H2, Gal],
4.414 [1 H, ddd (br. q), J5,4 ≤ 1, J5,6a 5.1, J5,6b 7.8, H5,
Gal], 4.470 (1 H, dd, J6a,6b 11.5, H6a, Gal), 4.520 (1 H,
dd, H6b, Gal), 4.701 [1 H, ddd (br. d), H5, GlcNAc],
4.950 (1 H, d, H1, Gal), 5.164 [1 H, dd (br. s), H3,
GlcNAc], 5.429 (1 H, dd, J3,4 3.5, H3, Gal), 5.439 [1 H,
d (br. s), H1, GlcNAc], 5.898 [1 H, dd (d), H4, Gal],
6.456 (1 H, d, NH, GlcNAc), 7.311, 7.412, and 7.498
[3 × 2 H, ttt, m-H(Bz)], 7.505, 7.543, 7.646 [3 × 1 H, ttt,
para-H(Bz)], 7.852, 7.970, and 8.063 [3 × 2 H, ddd,
o-H(Bz)];
3.687 (1 H, br. s, OH'), 3.857 [1 H, dd (br. s), J4,3 ≤ 1,
J4,5 ≤ 1, J3,2 ≤ 1, H4, GlcNAc], 3.945 [1 H, dd (br. s),
J
2,NH 9.5, J2,1 ≤ 1, H3, GlcNAc], 4.004 [1 H, ddd (br. d),
J2,NH 9.5, J2,1 ≤ 1, H2, GlcNAc], 4.103 (1 H, dd, J2,1 7.3,
J2,3 10, H2, Gal), 4.192 [1 H, dd (d), J6b,5 ≤ 1, H6b-
GlcNAc], 4.254 [1 H, ddd (t), J5,4 ≤ 1, J5,6a = J5,6b 6.5,
H5, Gal], 4.343 (1 H, dd, J6a,6b H1, H6a, Gal), 4.545
(1 H, dd, H6b, Gal), 4.679 [1 H, ddd (br. d), H5-
GlcNAc], 4.800 (1 H, d, H1, Gal), 5.383 [1 H, d (br. s),
H1-GlcNAc], 5.397 (1 H, dd, J3,4 ~ 3.5, H3, Gal), 5.858
[1 H, dd (d), H4, Gal], 6.480 (1 H, d, NH-GlcNAc),
7.246, 7.370, and 7.439 [3 × 2 H, ttt, metha-H(Bz)],
7.445, 7.504, and 7.586 [3 × ç, ttt, para-H(Bz)], 7.802,
7.945, and 8.017 [3 × 2 ç, 3 d, ortho-H(Bz)].
(B) By deacetylation of diacetate (Ib). A solution
of HCl in methanol [prepared from acetyl chloride
(2.4 ml, 34 mmol) and methanol (30 ml) at 0°ë] was
added to a solution of diacetate (Ib) (1.07 g, 1.4 mmol)
in a mixture of chloroform (20 ml) and methanol
(10 ml). The mixture was kept at room temperature for
20 h until disappearance (TLC) of the starting (Ib)
(Rf 0.39, 9 : 1 : 6 chloroform–methanol–hexane). The
reaction mixture was quenched with anhydrous sodium
acetate and evaporated to dryness. The residue was dis-
solved in chloroform (30 ml); the organic layer was
washed with water (10 ml), saturated NaHCO3, and
water; dried with anhydrous sodium sulfate; and con-
centrated. The residue was chromatographed in a gradi-
and the target disaccharide diol (Ia), yield 385 mg
(40%), identical to diol (Ia) obtained from (Ic) as
described above.
1,6-Anhydro-2-acetamido-3-é-(2,3,4-tri-é-ben-
zyl-a-L-fucopyranosyl)-4-é-[2-é-(2,3,4-tri-é-ben-
zyl-a-L-fucopyranosyl)-3,4,6-tri-é-benzoyl-b-D-
galactopyranosyl]-2-deoxy-b-D-glucopyranose (X).
A suspension of diol (Ia) (500 mg, 0.738 mmol), tetra-
ethylammonium bromide (1.06 g, 5.04 mmol), and
molecular sieves 4Å (1 g) in anhydrous methylene chlo-
ride (20 ml) was stirred at 20°ë for 2 h. A solution of
diisopropylethylamine (1.06 ml, 6.17 mmol) in DMF
(5 ml) and then a solution of fucosyl bromide (IV)
obtained from the corresponding thioglycoside (2.41 g,
5.04 mmol) and Br2 (287 µl, 5.56 mmol) in dichlo-
romethane (5 ml) were added. The reaction mixture
was stirred at room temperature for 48 h and filtered;
and the residue was washed on filter with chloroform
ent of isopropanol (0
10%) in 2 : 1 chloroform–
hexane to give (in the order of elution): the starting
diacetate (Ib); yield 40 mg (4%);
1,6-anhydro-2-acetamido-4-é-(2-é-acetyl-3,4,6-
tri-é-benzoyl-b-D-galactopyranosyl)-2-deoxy-b-D-
glucopyranose (Ic); yield 311 mg (31%), Rf 0.32
RUSSIAN JOURNAL OF BIOORGANIC CHEMISTRY Vol. 33 No. 1 2007

106
BYRAMOVA et al.
powder; [α]2D0 –157° (c 1, water); H NMR (D2O):
(5 × 5 ml). The filtrate was washed with 1 N HCl, water,
saturated NaHCO3, and water; dried; and evaporated to
dryness. The residue (the brownish-red syrup) was
chromatographed on silica gel (25 g) in a gradient of
1
1.242 and 1.255 (2 × 3 H, dd, J6,5 6.5, H6, Fuc1, H6,
Fuc2), 2.059 (3 H, s, Ac), 3.704 [1 H, ddd (br dq), I5,
Gal], 3.709 (1 H, dd, J2,1 7.8, J2,3 10, H2, Gal), 3.757
(2 H, m, H6a, Gal, H6b, Gal), 3.788 (1 H, dd, J2,1 4, J2,3
10.4, H2, Fuc1), 3.84 and 3.89 (5 H and 3 H, mm, H4,
GlcNAc, H6, GlcNAc, H3, Gal, H3, Fuc1, H4, Fuc1,
H2, Fuc2, H3, Fuc2, H4, Fuc2), 3.930 [1 H, dd (br s),
H3, GlcNAc], 3.966 [1 H, dd (br d), J4,3 3.5, H4, Gal],
4.063 [1 H, dd (br s), H2, GlcNAc], 4.129 [1 H, dq
(br q), H5, Fuc1], 4.222 [1 H, dd (br d), J6b,6a 7.8, H6b,
GlcNAc], 4.377 [1 H, dq (br q), H5, Fuc2], 4.680 (1 H,
d, J1,2 7.8, H1, Gal), 4.796 [1 H, ddd (br d), J5,6 5.5, I5,
GlcNAc], 5.062 (1 H, d, J1,2 4, H1, Fuc1), 5.329 (1 H,
d, J1,2 3.8, H1, Fuc2), 5.537 [1 H, d (br. d), I1, GlcNAc].
1,6-Anhydro-2-acetamido-4-é-[2-é-(2,3,4-tri-é-
acetyl-L-a-fucopyranosyl)-3,4,6-tri-é-acetyl-b-D-
galactopyranosyl]-3-é-(2,3,4-tri-é-acetyl-a-L-fuco-
pyranosyl)-2-deoxyb-D-glucopyranose (XIII). Ace-
tic anhydride (5 ml) was added to a solution of (XII)
(216 mg, 0.328 mmol) in pyridine (5 ml); the mixture
was kept for 48 h at room temperature and then was
cooled to 0°ë; methanol (7 ml) was added dropwise to
quench the excess of acetic anhydride; and methyl ace-
tate was removed in a vacuum. The residue was dis-
solved in chloroform (30 ml); washed with 1 N HCl,
water, and saturated NaHCO3; dried; and evaporated to
dryness. The residue was purified by LC on silica (25 g)
ethyl acetate (12
20%) in toluene. The fractions
containing (X) (Rf 0.58, 1 : 2 ethyl acetate–toluene)
were combined and evaporated to dryness to yield 1.2 g
of syrup, which was then debenzoylated without further
purification.
1,6-Anhydro-2-acetamido-3-é-(2,3,4-tri-é-ben-
zyl-a-L-fucopyranosyl)-4-é-[2-é-(2,3,4-tri-é-ben-
zyl-a-L-fucopyranosyl)-b-D-galactopyranosyl]-2-
deoxy-b-D-glucopyranose (XI). A 2 N solution of
sodium methylate in methanol (2.5 ml) was added to a
solution of (X) (1.2 g) in anhydrous methanol (25 ml).
The mixture was kept for 17 h at room temperature,
quenched with acetic acid (75 µl), and concentrated.
The residue was chromatographed on silica gel (25 g)
in a gradient of isopropanol (0
12%) in 1 : 2 chlo-
roform–hexane to give 504 mg (57%) of triol (XI); Rf
0.47 (4 : 2 : 1 chloroform–hexane–isopropanol), [α]2D0
1
–72° (c 3, chloroform). H NMR (CD3OD): 1.347 and
1.388 (2 × 3 H, dd, J6,5 6.5, H6, Fuc1 and H6, Fuc2),
2.044 (3 H, s, OAc), 3.703 (1 H, dd, J5,6a 6.3, J5,6b 5.9,
H5, Gal), 3.855 (1 H, dd, J6‡,6b 7.2, J6a,5 6.3, H6a,
GlcNAc), 3.904 (4 H, m, H4, GlcNAc, H6a, Gal, H6b,
Gal, H4, Fuc1), 3.970 [1 H, dd (br. d), H4, Fuc1], 3.992
(2 H, m, H2, Gal, H3, Gal), 4.007 [1 H, dd (br. s), H3,
GlcNAc], 4.052 [1 H, dd (br. d), J4,3 2, H4, Gal], 4.094
(1 H, dd, J3,2 10.3, J3,4 2.8, H3, Fuc1), 4.165 (1 H, dd,
in a gradient of ethyl acetate (30
80%) in toluene
to give 319 mg (94%) of peracetate (XIII); Rf 0.33 (3 :
1 ethyl acetate–toluene), Rf 0.42 (4 : 2 : 1 hexane–chlo-
roform–isopropanol); [α]2D0 –127 (Ò 1, chloroform); 1H
NMR: 1.171 and 1.198 (2 × 3 H, dd, J6,5 = J6,5 6.5, H6,
Fuc1, H6, Fuc2), 1.988, 2.000, 2.008, 2.020, 2.039,
2.067, 2.110, 2.143, 2.162, and 2.165 (10 × 3 H, 10 s,
J
2,3 10.3, J2,1 3.6, H2, Fuc1), 4.175 (2 H, m, H2, Fuc2,
H3, Fuc2), 4.189 [1 H, dq (br. d), H5, Fuc1], 4.197
[1 H, ddd (br. s), H2, GlcNAc], 4.313 (1 H, dd, J6b,5 ~ 1,
H6b, GlcNAc), 4.467 [1 H, dq (br q), H5, Fuc2], 4.743
(1 H, d, J1,.2 7, H1, Gal), 4.787 and 4.796 (2 × 1 H, dd,
J 11.2, CH-Ar), 4.803 [1 H, ddd (br. d), H5, GlcNAc], 10An), 3.725 [1 H, dd (br. s), H4, GlcNAc], 3.808 (1 H,
4.841 (1 H, d, J 11.7, CH-Ar), 4.92–5.02 (7 H, m, CH- dd, J6a,6b 7.2, J6a,5 6.1, H6, GlcNAc), 3.886 (1 H, dd, J2,1
Ar), 5.090 and 5.105 (2 × 1 H, dd, J 11.2, CH-Ar),
5.343 (1 H, d, J1,2 3.6, H1, Fuc1), 5.414 (1 H, d, J1,2 3.1,
H1, Fuc2), 5.465 (1 H, d (br. s), H1, GlcNAc), 7.44–
7.61 (30 H, m, Ar).
7.7, J2,3 10, H2, Gal), 3.892 [1 H, ddd (br. dd), H5, Gal],
3.931 [1 H, dd (br s), H3, GlcNAc], 4.005 [1 H, ddd
(br d), J2,HN 9.6, H2, GlcNAc], 4.006 (1 H, dd, J6a,6b
11.4, J6a,5 6.7, H6a, Gal), 4.114. [1 H, dq (br. q), H5,
Fuc1], 4.161 (1 H, dd, J6b,5 6.4, H6b, Gal), 4.190 [1 H,
dd (br. d), H6b, GlcNAc], 4.583 (1 H, d, H1, Gal),
4.585 [1 H, ddd (br. d), H5, GlcNAc], 4.620 [1 H, dq
(br q), H5, Fuc2], 5.029 (1 H, dd, J2,1 3.7, J2,3 11, H2,
Fuc1), 5.049 (1 H, dd, J3,4 3.5, H3, Gal), 5.092 (1 H, dd,
J2,1 3.9, J2,3 10.8, H2, Fuc2), 5.272 (1 H, dd, J3,4 3.3, H3,
Fuc2), 5.299 [1 H, dd (br. d), H4, Fuc1], 5.302 [1 H, d
(br. s), H1, GlcNAc], 5.321 [1 H, dd (br. s), H4, Gal],
5.328 [1 H, dd (br. s), H4, Fuc2], 5.352 (1 H, dd, J3,4
3.3, H3, Fuc1), 5.431 (1 H, d, H1, Fuc2), 5.470 (1 H, d,
H1, Fuc1), 6.013 (1 H, d, NH, GlcNAc).
1,6-Anhydro-2-acetamido-3-é-a-L-fucopyrano-
syl-4-é-[2-é-a-L-fucopyranosyl-b-D-galactopyra-
nosyl]-2-deoxy-b-D-glucopyranose (XII). Palladium
on carbon (10%, 10 mg) was added to a solution of triol
(XI) (450 mg, 0.376 mmol) in a mixture of methanol
(24 ml) and ethyl acetate (6 ml). The reaction mixture
was subjected to hydrogenolysis at 20°ë and atmo-
spheric pressure under stirring for 20 h. The reaction
was monitored by TLC [Rf of the starting triol (XI) is
0.82 (4 : 3 : 2 isopropanol–ethyl acetate–water), Rf of
the target (XII) is 0.25 (4 : 3 : 2 isopropanol–ethyl ace-
tate–water)]. The suspension was filtered, the precipi-
2-Acetamido-1,6-di-é-acetyl-3-é-(2,3,4-tri-é-
tate was washed on filter with methanol, and the filtrate acetyl-a-L-fucopyranosyl)-4-é-[2-é-(2,3,4-tri-é-
was evaporated to dryness to give 236 mg (96%) of tet- acetyl-a-L-fucopyranosyl)-3,4,6-tri-é-acetyl-b-D-
rasaccharide (XII) as white downy semicrystalline galactopyranosyl]-2-deoxy-a,b-D-glucopyranose
RUSSIAN JOURNAL OF BIOORGANIC CHEMISTRY Vol. 33 No. 1 2007

1,6-ANHYDRO-N-ACETYL-β-D-GLUCOSAMINE
107
(XIV). A 10 vol % solution of concentrated H2SO4 in
acetic acid (0.5 ml) was added to a solution of anhydro
derivative (XIII) (289 mg, 0.279 mmol) in acetic acid
(5 ml) and acetic anhydride (5 ml); the mixture was
kept at room temperature for 40 h. According to TLC,
the mixture contained peracetate (XIV) as the mixture
of α- and β-anomers and oxazoline (XVI) with Rf 0.44,
0.37, and 0.58, respectively (4 : 2 : 1 hexane–chloro-
form–isopropanol). Ground anhydrous NaOAc (0.5 g)
and then pyridine (25 ml) were added to the reaction
mixture; the mixture was cooled to 0°ë; and water
(15 ml) was added carefully portionwise. The mixture
was kept for 1 h at room temperature and diluted with
chloroform. The chloroform layer was washed with 1 N
HCl, water, saturated NaHCO3, and water; dried; and
evaporated to dryness. The residue, a mixture of ano-
meric acetates (XIV) and the product of oxazoline
hydrolysis as anomeric derivatives (XV) with Rf 0.31
and 0.21 (4 : 2 : 1 hexane–chloroform–isopropanol)
according to TLC, was subjected to additional acetyla-
tion with acetic anhydride (4 ml) in pyridine (4 ml).
After 16 h, the mixture was cooled to 0°ë and
quenched with methanol as described above for obtain-
ing acetate (XIII). The solution was concentrated; the
residue was diluted with chloroform; extracted with 1
N HCl, water, saturated NaHCO3, and water; dried; and
evaporated to dryness. The residue (370 mg) was chro-
matographed on a silica gel column (25 g) in a gradient
2-Acetamido-6-é-acetyl-3-é-(2,3,4-tri-é-acetyl-
a-L-fucopyranosyl)-4-é-[2-é-(2,3,4-tri-é-acetyl-
a-L-fucopyranosyl)-3,4,6-tri-é-acetyl-b-D-galacto-
pyranosyl]-2-deoxy-a,b-D-glucopyranose
(XV).
Hydrazine acetate (100 mg) was added to a solution of
acetate (XIV) (218 mg, 192 µmol) in acetonitrile
(10 ml); the mixture was stirred at room temperature
for 40 h and then concentrated. The residue was diluted
with chloroform; washed with 0.5 N HCl, saturated
NaHCO3, and water; dried; and evaporated to dryness.
The residue was chromatographed on silica gel in a gra-
dient of isopropanol (4
9%) in chloroform to give
167 mg (79%) of monohydroxy derivative (XV) as a
mixture of anomers (Rf 0.31 and 0.21, 4 : 2 : 1 hexane–
chloroform–isopropanol); [α]2D0 –111° (c 1, chloro-
form, 1.5 h) and 15 mg (7%) of the starting (XIV).
3-Trifluoroacetamidopropyl 2-acetamido-6-é-
acetyl-3-é-(2,3,4-tri-é-acetyl-a-L-fucopyranosyl)-
4-é-[2-é-(2,3,4-tri-é-acetyl-a-L-fucopyranosyl)-
3,4,6-tri-é-acetyl-b-D-galactopyranosyl]-2-deoxy-
b-D-glucopyranoside (XVII). Collidine (200 µl,
1.52 mmol) and then mesyl chloride (60 µl, 0.77 mmol)
were added to a solution of (XV) (156 mg, 142 µmol)
in anhydrous methylene chloride (4.5 ml). After 5 h, the
solution containing oxazoline (XVI) (Rf 0.58, 4 : 2 : 1
hexane–chloroform–isopropanol) as the only product
was diluted with chloroform, washed with saturated
NaHCO3 and water, dried, concentrated, and dried in a
vacuum (1 mm Hg) to give (XVI). It was dissolved in
anhydrous benzene (7 ml), 3-trifluoroacetamidopro-
panol (1 ml, 8.19 mmol) was added, and then a solution
of anhydrous TsOH in anhydrous toluene was added at
vigorous stirring. The addition was controlled by mea-
suring pH of the sample of the reaction mixture with
wet indicator paper, so that pH maintained within 3–4.
The reaction mixture was stirred for 3 h at room tem-
perature; diluted with chloroform; washed with 1 N
HCl, water, saturated NaHCO3, and water; dried; con-
centrated, and dried in a vacuum. The residue was chro-
matographed on a silica gel column (15 g) in a gradient
of isopropanol (4
13%) in 2 : 1 hexane–chloroform
to give 284 mg (89%) of acetate (XIV) as a mixture of
anomers. The sample of the mixture was rechromato-
graphed for analytical purposes to give the minor
β-anomer, Rf 0.44 (4 : 2 : 1 hexane–chloroform–isopro-
panol), [α]2D0 –109° (Ò 1, chloroform) and the major
α-anomer, Rf 0.37 (4 : 2 : 1 hexane–chloroform–isopro-
panol), [α]2D0 –80° (Ò 1, chloroform); H NMR: 1.194
1
(6 H, dd, J6,5 6.6, H6, Fuc1, H6, Fuc2), 1.962, 1.964,
1.970, 1.992, 2.018, 2.093, 2.112, 2.148, 2.157, 2.162,
2.166, and 2.167 (12 × 3 H, 12 s, 12 Ac), 3.736 (1 H,
dd, J2,1 8, J2,3 10, H2, Gal), 3.858 [1 H, ddd (br dd), H5,
Gal], 3.882 (1 H, dd, J3,2 10.3, J3,4 8.3, H3, GlcNAc),
4.010 (2 H, m, H4, H5, GlcNAc), 4.262 (1 H, dd, J6‡,6b
12.2, J6a,5 4.5, H6a, GlcNAc), 4.294 (1 H, dd, J6a,6b 11.6,
J6a,5 7.6, H6a, Gal), 4.456 [1 H, dq (br q), H5, Fuc1],
4.473 (1 H, d, J1,2 8, H1, Gal), 4.494 (1 H, dd, J6b,5 6.5,
H6b, Gal), 4.542 (1 H, dd, J6b,5 1.5, H6b, GlcNAc),
4.607 (1 H, ddd, J2,1 3.9, J2,NH 10.4, H2, GlcNAc),
4.957 [1 H, dq (br q), H5, Fuc2], 5.018 (1 H, dd, J3,4 3.7,
of isopropanol (5
12%) in 2 : 1 hexane–chloroform
to give 144 mg (81%) of glycoside (XVII), [α]2D0 –111°
(c 2, chloroform), Rf 0.32 (4 : 2 : 1 hexane–chloroform–
isopropanol) and 0.47 (4 : 2 :1 hexane–chloroform–eth-
anol); 1H NMR: 1.196 and 1.203 (6 H, dd, J6,5 6.5, H6,
Fuc1, H6, Fuc2), 1.967, two 1.971, 1.987, 2.007, 2.072,
2.121, 2.147, two 2.152, and 2.1156 (11 × 3 H, 11 s, 11
An), 3.290 (1 H, ddd, ëHNH), 3.590 (4 H, m, ëH'NH,
OCH and ëëç2ë), 3.528 (1 H, ddd, J5,6a 2.2, J5,6b 5, I5,
H3, Gal), 5.031 (1 H, dd, J2,1 3.9, J2,3 11, H2, Fuc1), GlcNAc), 3.640 (1 H, ddd, J2,1 8.3, J2,3 9.5, J2,NH 9, I2,
GlcNAc), 3.764 (1 H, dd, J2,1 8, J2,3 10, H2, Gal), 3.863
[1 H, ddd (br. dd), J5,6a 7.5, J5,6b 6, H5, Gal], 3.894 (1 H,
dd, J4,3 9.5, J4,5 9.5, H4, GlcNAc), 3.908 (ddd, JOCH’,OCH
10, OCH’), 4.043 (1 H, dd, H3, GlcNAc), 4.233 (1 H,
dd, J6‡,6b 12.5, H6a, GlcNAc), 4.265 (1 H, dd, J6a,6b
11.5, H6a, Gal), 4.422 [1 H, dq (br. q), H5, Fuc2], 4.500
5.057 (1 H, dd, J2,1 3.9, J2,3 11, H2, Fuc2), 5.147 (1 H,
dd, J3,4 3.3, H3, Fuc1), 5.196 (1 H, dd, J3,4 3.3, H3,
Fuc2), 5.261 (1 H, d, NH, GlcNAc), 5.308 [1 H, dd (br
d), H4, Fuc1], 5.342 (1 H, d, H1, Fuc1), 5.358 [1 H, dd
(br d), H4, Gal], 5.374 (1 H, d, H1, Fuc2), 5.387 [1 H,
dd (br. d), H4, Fuc2], 5.954 (1 H, d, H1, GlcNAc).
RUSSIAN JOURNAL OF BIOORGANIC CHEMISTRY Vol. 33 No. 1 2007

108
BYRAMOVA et al.
(1 H, dd, H6b, Gal), 4.518 (1 H, d, H1, Gal), 4.630 ences) for registration of NMR spectra and to
(1 H, d, H1, GlcNAc), 4.696 (1 H, dd, H6b, GlcNAc), G.V. Pazynina for participation in the synthesis of the
4.926 [1 H, dq (br. q), H5, Fuc1], 5.007 (1 H, dd, J2,1 starting 1,6-anhydro-GlcNAc.
3.5, J2,3 11, H2, Fuc2), 5.010 (1 H, dd, J2,1 3.5, J2,3 11,
H2, Fuc1), 5.028 (1 H, dd, J3,4 3.5, H3, Gal), 5.138
(1 H, dd, J3,4 3.5, H3, Fuc2), 5.194 (1 H, dd, J3,4 3.5, H3,
REFERENCES
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3-Aminopropyl 2-acetamido-2-deoxy-3-é-(a-L-
fucopyranosyl)-4-é-[2-é-(a-L-fucopyranosyl)-3,4,6-
b-D-galactopyranosyl]-b-D-glucopyranoside (XVIII).
Ion-exchange resin Amberlist A-26 (OH−) (2 ml) was
added to a solution of glycoside (XVII) (61.6 mg, 49.3
µmol) in a mixture of methanol (8 ml) and water (0.3
ml); the mixture was stirred for 20 h at room tempera-
ture and filtered; the resin was washed on filter with
methanol and 2 : 1 methanol–water; and the filtrate was
concentrated and dried in a vacuum to give 34.8 mg
(96%) of aminopropyl glycoside (XVIII). Rf 0.49
(3 : 1 : 1 : 0.3 ethanol–water–pyridine–acetic acid);
[α]2D0 –118° (c 1.5, water); 1H NMR (D2O): 1.232 and
1.264 (6 H, dd, J6,5 6.7, H6, Fuc1, H6, Fuc2), 1.831 (2
H, m, CCH2C) 2.885 (2 H, t, ëç2N), 2.034 (3 H, s,
NHAc), 3.660 (1 H, m, OCH), 3.983 (1 H, m, OCH’),
4.252 [1 H, dq (br q), H5, Fuc2], 4.518 (1 H, d, J1,2 7.7,
H1, Gal), 4.630 (1 H, d, J1,2 8.8, I1, GlcNAc), 4.864 [1
H, dq (br q), H5, Fuc1], 5.101 (1 H, d, J1,2 4, H1, Fuc1),
5.273 (1 H, d, J1,2 3, H1, Fuc2); 13C NMR (D2O):
102.21 (N1, GlcN), 101.47 (C1, Gal), 100.66 (C1,
Fuc2), 99.84 (C1, Fuc1), 77.57 (C2, Gal), 76.79 (C3,
GlcN), 76.10 (C5, GlcN, C5, Gal), 74.78 (C3, Gal),
74.54 (C4, GlcN), 73.15 (C4, Fuc2), 72.92 (C4, Fuc1),
70.95 (C3, Fuc2), 70.39 (C3, Fuc1), 69.96 (C4, Gal),
69.48 (C2 Fuc1, C2 Fuc2), 68.90 (OC), 68.05 (C5,
Fuc1, C5, Fuc2), 62.67 (C6, Gal), 61.13 (C6, GlcN),
38.77 (NC), 30.57 (CCC), 23.40 (CCON), 18.62 (C6,
Fuc1, C6, Fuc2).
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Izv. Akad. Nauk SSSR, Ser. Khim., 1985, no. 5, pp. 1122–
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Backinowsky, L.V., Tetrahedron, 1985, vol. 16,
pp. 3363–3375.
ACKNOWLEDGMENTS
We are grateful to A.S. Shashkov (Zelinsky Institute
of Organic Chemistry, Russian Academy of Sciences)
and I.V. Maslennikov (Shemyakin–Ovchinnikov Insti-
tute of Bioorganic Chemistry, RussianAcademy of Sci-
RUSSIAN JOURNAL OF BIOORGANIC CHEMISTRY Vol. 33 No. 1 2007

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RUSSIAN JOURNAL OF BIOORGANIC CHEMISTRY Vol. 33 No. 1 2007