Synthesis of oligosaccharides related to the HNK-1 antigen. 5. Synthesis of a sulfo-mimetic of the HNK-1 antigenic trisaccharide

Article abstract of DOI:10.1007/s11172-007-0258-y

2-Aminoethyl 3,6-di-O-sulfo-β-D-glucopyranosyl-(1→3)-β-D- galactopyranosyl-(1→4)-2-acetamido-2-deoxy-β-D-glucopyranoside, which is the sulfo-mimetic of the antigenic trisaccharide HNK-1, and the corresponding monosulfates, viz., 2-aminoethyl 3-O-sulfo-and 2-aminoethyl 6-O-sulfo-β-D-glucopyranosyl-(1→3)-β-D-galactopyranosyl-(1→ 4)-2-acetamido-2-deoxy-β-D-glucopyranosides, were synthesized. 2-Azidoethyl 2,4-di-O-benzoyl-β-D-glucopyranosyl-(1→3)-2,4,6-tri-O-benzoyl-β- D-galactopyranosyl-(1→ 4)-2-acetamido-3,6-di-O-benzyl-2-deoxy-β-D- glucopyranoside served as the common precursor for the sulfated trisaccharides. This compound was synthesized according to the [2+1] pattern from monosaccharidic precursors: 3,6-di-O-acetyl-2,4-di-O-benzoyl-D-glucopyranosyl trichloroacetimidate, allyl 2-O-benzoyl-4,6-O-benzylidene-β-D- galactopyranoside, and 2-azidoethyl 2-acetamido-3,6-di-O-benzyl-2-deoxy-β- D-glucopyranoside. The structures of the glycosyl donors and glycosylation conditions were optimized for the efficient synthesis of the glucosyl-β-(1→3)-galactose disaccharide block and its subsequent transformation into the target trisaccharide sequence.

Full text of DOI:10.1007/s11172-007-0258-y

Russian Chemical Bulletin, International Edition, Vol. 56, No. 8, pp. 1655—1670, August, 2007
1655
Synthesis of oligosaccharides related to the HNKꢀ1 antigen.
5.* Synthesis of a sulfoꢀmimetic of the HNKꢀ1 antigenic trisaccharide**
E. V. Sukhova,aꢀ A. V. Dubrovskii,b Yu. E. Tsvetkov,a and N. E. Nifantieva
aN. D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences,
47 Leninsky prosp., 119991 Moscow, Russian Federation.
Fax: +7 (499) 135 8784. Eꢀmail: nen@ioc.ac.ru
bHigher Chemical College, Russian Academy of Sciences,
9 Miusskaya pl., 125047 Moscow, Russian Federation.
2ꢀAminoethyl 3,6ꢀdiꢀOꢀsulfoꢀβꢀDꢀglucopyranosylꢀ(1→3)ꢀβꢀDꢀgalactopyranosylꢀ(1→4)ꢀ2ꢀ
acetamidoꢀ2ꢀdeoxyꢀβꢀDꢀglucopyranoside, which is the sulfoꢀmimetic of the antigenic trisacꢀ
charide HNKꢀ1, and the corresponding monosulfates, viz., 2ꢀaminoethyl 3ꢀOꢀsulfoꢀ and
2ꢀaminoethyl 6ꢀOꢀsulfoꢀβꢀDꢀglucopyranosylꢀ(1→3)ꢀβꢀDꢀgalactopyranosylꢀ(1→4)ꢀ2ꢀacetꢀ
amidoꢀ2ꢀdeoxyꢀβꢀDꢀglucopyranosides, were synthesized. 2ꢀAzidoethyl 2,4ꢀdiꢀOꢀbenzoylꢀβꢀDꢀ
glucopyranosylꢀ(1→3)ꢀ2,4,6ꢀtriꢀOꢀbenzoylꢀβꢀDꢀgalactopyranosylꢀ(1→4)ꢀ2ꢀacetamidoꢀ3,6ꢀdiꢀ
Oꢀbenzylꢀ2ꢀdeoxyꢀβꢀDꢀglucopyranoside served as the common precursor for the sulfated trisacꢀ
charides. This compound was synthesized according to the [2+1] pattern from monosaccharidic
precursors: 3,6ꢀdiꢀOꢀacetylꢀ2,4ꢀdiꢀOꢀbenzoylꢀDꢀglucopyranosyl trichloroacetimidate, allyl
2ꢀOꢀbenzoylꢀ4,6ꢀOꢀbenzylideneꢀβꢀDꢀgalactopyranoside, and 2ꢀazidoethyl 2ꢀacetamidoꢀ3,6ꢀ
diꢀOꢀbenzylꢀ2ꢀdeoxyꢀβꢀDꢀglucopyranoside. The structures of the glycosyl donors and
glycosylation conditions were optimized for the efficient synthesis of the glucosylꢀβꢀ(1→3)ꢀ
galactose disaccharide block and its subsequent transformation into the target trisaccharide
sequence.
Key words: HNKꢀ1 antigen, sulfoꢀmimetic, glycosylation, levoglucosan.
The HNКꢀ1 carbohydrate antigens, parts of the carboꢀ
hydrate chains of glycolipids and glycoproteins expressed
on nervous tissue cells, include epitopes of
the autoantibodies responsible for the development of seꢀ
rious diseases, viz., peripheral neuropathies.2 Although
the role of the HNKꢀ1 antigens has not been fully eluciꢀ
dated as yet, it was shown that they also determine the
adhesion of nervous cells and the growth and developꢀ
ment of nervous tissues3—5 and participate in the nerve
impulse transmission.6 A common structural unit of the
HNKꢀ1 antigenic oligosaccharides is the trisaccharide
–SO3ꢀ3GlcAβꢀ(1→3)ꢀGalβꢀ(1→4)ꢀGlcNAcβ (1) conꢀ
R1 = R2 = SO3Na (2a); R1 = H, R2 = SO3Na (2b);
R
taining a sulfo group at the O(3) atom of the glucuronic
acid residue.7,8
1 = SO3Na, R2 = H (2c)
This work continues our research dealing with the
synthesis of HNKꢀ1 antigenic oligosaccharides1,9—11 and
is devoted to the synthesis of a disulfated mimetic 2a of
the trisaccharide sequence 1 in which the sulfo group at
the О(6) atom of the glucose residue mimics the carboxy
group of glucuronic acid in structure 1. Apart from comꢀ
pound 2a, we also prepared the corresponding 3ꢀ and
6ꢀmonosulfates 2b and 2c. Sulfated oligosaccharides 2
were obtained as 2ꢀaminoethyl glycosides for their subseꢀ
quent transformation into molecular probes and neoꢀ
glycoconjugates, which would be used to elucidate the
possible role of anionic groups in positions 3 and 6 in the
biological recognition of the HNKꢀ1 antigens.
* For Part 4, see Ref. 1.
The retrosynthetic analysis (Scheme 1) has shown that
diol 3 is the common precursor of trisaccharides 2a—c;
** Dedicated to Academician V. A. Tartakovsky on the occasion
of his 75th birthday.
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 8, pp. 1593—1607, August, 2007.
1066ꢀ5285/07/5608ꢀ1655 © 2007 Springer Science+Business Media, Inc.

1656
Russ.Chem.Bull., Int.Ed., Vol. 56, No. 8, August, 2007
Sukhova et al.
Scheme 1
Scheme 2
we intended to obtain 3 from trisaccharide 4 containing
temporary protective groups at the О(3) and О(6) atoms
of the glucose residue. In the synthesis of trisaccharide 4,
benzoyl and benzyl groups can be used as the permanent
protective groups, while acetyl can serve as the temporary
protective group. The latter can selectively be removed in
the presence of benzoyl groups by mild acidꢀcatalyzed
methanolysis.12 The synthesis of trisaccharide 4 was
planned according to the [2+1] pattern using the disacꢀ
charide glucosylꢀβꢀ(1→3)ꢀgalactose 5 as the glycosyl doꢀ
nor and NꢀacetylꢀDꢀglucosamine derivative 6 as the acꢀ
ceptor. The monosaccharide precursors of disaccharide 5,
namely, compounds 7 and 8, can in turn be prepared
from levoglucosan and Dꢀgalactose βꢀpentaacetate.
3,6ꢀDiꢀOꢀacetylated derivatives, bromide 14 and
trichloroacetimidate 15, which correspond to the gluꢀ
cose residue 7, were used as the glycosylating agents
(Scheme 2).
The synthesis of 2,4ꢀdiꢀOꢀbenzoylated glucopyranose
derivatives from precursors with the 4C1ꢀconformation of
the pyranose ring is a nontrivial task, whereas the use of
levoglucosan 9 with the inverted ring conformation makes
possible rather efficient oneꢀstep 2,4ꢀdibenzoylation.13
Acetylation of the resulting dibenzoate 10 afforded acꢀ
etate 11, which was then subjected to acetolysis to give
1,3,6ꢀtriacetate 12 in quantitative yield. This product reꢀ
acted with HBr in AcOH affording glucosyl bromide 14 in
quantitative yield. For the preparation of trichloroꢀ
acetimidate 15, compound 12 was first selectively
Reagents and conditions: i. BzCl/pyridine (40%);
ii. Ac2O/pyridine (96%); iii. H2SO4(cat.)/Ac2O (98%);
iv. N2H4•HOAc/DMF (88%); v. 33% HBr in AcOH,
Ac2O/CH2Cl2 (99%); vi. CCl3CN, DBU/CH2Cl2 (81%).

Synthesis of oligosaccharides
Russ.Chem.Bull., Int.Ed., Vol. 56, No. 8, August, 2007
1657
deacetylated by treatment with hydrazinium acetate14 to
give hemiacetal 13 in 88% yield. The reaction of the prodꢀ
uct with CCl3CN in the presence of DBU10 furnished
trichloroacetimidate 15 in 81% yield.
The azidoethyl glycoside of glucosamine 6 was preꢀ
pared as shown in Scheme 3. The reaction of chloride 16
(see Ref. 15) with 2ꢀchloroetanol in the presence of merꢀ
curic cyanide afforded 2ꢀchloroethyl glycoside 17 in
73% yield. The βꢀconfiguration of the glycosidic bond in
product 17 was confirmed by the value of the coupling
constant J1,2 in the H NMR spectrum (Table 1), equal
to 8.3 Hz, while incorporation of the βꢀchloroethyl aglyꢀ
cone into the molecule is confirmed by the signal at δ 41.8
(Table 2) characteristic of the CH2Cl group in the
13C NMR spectrum. The reaction of chloro derivative 17
with NaN3 in the presence of a phaseꢀtransfer catalyst
1
Table 1. 1H NMR data for derivatives 2—4, 5b, 6, 10—18, 20—21, 25—27, 29, 30, 32—35, and 36—40 (CDCl3)
Comꢀ
pound
Residue
δ
J/Hz
H(1) H(2) H(3) H(4)
H(5)
3.99
H(6a)
4.33
H(6b) J1,2
J2,3
J3,4
J4,5
J5,6a J5,6b J6a,6b
2aa
2ba
2ca
3
Glc
Gal
4.77 3.58 4.32 3.65
4.52 3.69 3.83 4.22
4.19
7.9
7.9
8.2
8.0
7.9
8.3
7.9
7.9
7.9
7.6
8.0
6.9
7.6
8.6
9.2
9.1
3.1
5.8
<1
<1
GlcNAc 4.56 3.78
Glc
Gal
GlcNAc 4.53 3.79
Glc
Gal
GlcNAc 4.56 3.77
Glc
Gal
GlcNAc 4.46 3.62 3.87 4.00
Glc
Gal
4.77 3.56 4.32 3.63
4.58 3.72 3.85 4.18
9.1
8.7
9.1
3.0
4.67 3.40 3.52 3.46
4.52 3.69 3.82 4.22
3.66
4.33
4.18
9.1
3.0
9.4
<1
<1
5.6
9.7
4.87 4.92 3.93 5.01
4.68 5.56 3.99 5.93
3.70
3.90
3.36
3.86
3.93
3.32
3.84
4.37
3.57
4.82
4.80
3.74
4.31
3.58
4.31
4.38
3.55
4.30
4.34
3.55
4.27
3.45
4.15
4.23
3.45
4.17
4.07
7.8
8.4
6.8
7.7
8.6
9.5
3.5
6.8
9.6
3.0
9.5
<1
4.3
<1
4.9
3.2
10.4
11.4
11.4
10.4
12.2
10.9
10.4
7.5
4
4.84 5.09 5.43 5.30
4.60 5.50 3.98 5.78
9.6
<1
4.1
4.7
3.6
4.3
GlcNAc 4.52 3.55 3.86 3.98
Glc
Gal
5b
5.06 5.30 5.48 5.38
4.60 5.54 4.07 4.35
7.8
7.9
8.2
<1
7.9
8.0
9.3
<1
9.6
<1
9.3
<1
<1
9.6
<1
8.4
<1
<1
6
GlcNAc 4.96 3.29 4.08 3.62
3.71—3.79
4.38
4.24
3.3
<1
<1
10
11
12
13b
14
15
17
18
20
21
25
26
Glc
Glc
Glc
Glc
Glc
Glc
5.70 4.94 4.11 5.02
5.64 4.90 5.19 4.94
6.55 5.36 5.89 5.50
5.69 5.14 5.97 5.44
5.71 5.19 5.98 5.44
6.78 5.45 5.99 5.55
3.88
3.87
3.8
5.3
5.2
<1
<1
7.6
4.17—4.34
3.3
3.4
3.2
3.5
8.4
8.3
8.3
8.3
9.8
10.3
7.3
10.2
8.5
8.5
9.6
10.7 10.0
4.45
4.48
4.43
3.73
3.71
4.35
3.39
3.95
3.92
4.25
3.87
3.36
3.61
3.48
3.91
3.62
3.81
4.12
3.89
4.67
3.94
4.67
4.23
4.25—4.29
4.23
9.9
9.9
9.9
9.6
10.4
9.6
9.9
10.0
10.0
9.7
3.5
4.27
4.16
4.14
3.81
4.23
4.24
4.31
3.96
4.08
3.92
4.13
4.08
4.32
4.01
4.26
4.54
4.34
4.46
4.30
4.55
4.27
4.29
4.23
3.58
3.62
GlcNAc 4.81 3.88 5.33 5.07
GlcNAc 4.82 3.79 5.33 5.06
GlcNAc 5.11 3.24 4.37 3.69
GlcNAc 4.67 3.51 3.88 3.48
4.9
4.8
4.9
4.1
5.2
2.5
2.4
10.2 10.4
10.1 10.1
12.3
12.3
9.7
10.0 10.0
Glc
Glc
Gal
Glc
Gal
Glc
Gal
Glc
Gal
Glc
Gal
Glc
Gal
Glc
Gal
4.73 5.39 5.65 5.43
4.90 5.38 5.61 5.46
4.51 5.29 4.47 4.30
5.70 4.49 5.25 5.04
4.48 5.61 3.81 4.03
4.73 4.92 5.01 5.03
4.62 5.58 3.97 4.33
4.90 5.33 5.52 5.31
4.55 5.45 3.93 4.18
4.88 5.12 5.40 5.30
4.65 5.58 4.21 5.84
5.03 5.13 5.45 5.33
5.65 5.43 4.61 5.91
5.02 5.15 5.46 5.32
6.71 5.72 4.58 6.01
4.29 10.0
9.7
9.5
9.5
2.3
9.5
9.8
6.3
<1
3.6
9.2
9.8
9.7
2.9
12.3
4.05
4.21
4.14
4.32
4.25
4.33
4.17
3.88
4.14
4.47
4.19
4.43
4.20
4.38
7.8
9.6
5.3
27
29
30c
32
33
34
9.1
<1
9.2
<1
8.0
<1
9.7
<1
9.7
<1
9.7
<1
3.1
<1
2.4
<1
5.5
<1
4.2
<1
12.2
11.4
12.2
7.8
8.0
7.9
8.0
7.7
7.8
7.8
2.8
7.7
3.7
9.1
10.1 10.2
9.7
8.4
7.8
8.0
7.8
10.4
7.8
10.3
9.6
4.5
9.6
3.4
9.6
3.2
9.6
3.2
2.9
6.7
3.1
5.1
3.0
6.0
3.0
4.3
5.5
5.0
4.6
7.3
4.7
6.0
4.9
7.6
12.3
11.4
12.3
11.6
12.2
11.6
12.2
11.8
(to be continued)

1658
Russ.Chem.Bull., Int.Ed., Vol. 56, No. 8, August, 2007
Sukhova et al.
Table 1 (continued)
Comꢀ
pound
Residue
δ
J/Hz
H(1) H(2) H(3) H(4)
H(5)
H(6a)
H(6b) J1,2
J2,3
J3,4
J4,5
J5,6a J5,6b J6a,6b
35
Glc
Gal
Glc
Gal
4.90 5.12 5.41 5.31
4.64 5.61 4.24 5.90
4.95 5.07 4.86 5.24
4.73 5.51 4.31 5.92
3.84
4.17
4.19
4.09
3.17
4.21
3.96
3.11
4.18
4.14
3.18
4.13
3.88
3.46
4.40
4.18
3.18
4.26
4.12
3.12
4.20
3.96
3.10
4.18
4.15
3.19
4.16
4.50
3.20
4.19
4.29
3.13
4.07
4.49
3.18
4.31
4.52
4.29
4.41
3.60
4.47
4.29
3.59
4.25
4.41
3.65
4.57
4.32
3.56
4.30
4.42
3.67
4.29
4.42
3.61
4.48
4.28
3.56
4.22
4.40
3.63
4.21
4.68
3.43
4.45
4.53
3.39
4.21
4.69
3.45
4.16
4.44 10.0
7.7
7.7
9.8
8.3
8.3
9.4
8.0
9.8
9.6
3.3
9.1
3.1
9.7
<1
9.1
<1
3.1
5.1
4.6
7.2
12.1
11.8
36ad
4.18
4.08
3.42
4.47
3.87
3.40
4.24
4.01
3.48
4.57
4.26
3.48
4.30
7.7
8.1
8.2
7.9
8.0
8.4
8.7
8.5
4.5
11.3
GlcNAc 4.39 3.78 3.56 4.00
Glc
Gal
GlcNAc 4.38 3.80 3.55 3.98
Glc
Gal
GlcNAc 4.38 3.80 3.91 4.01
Glc
Gal
GlcNAc 4.50 3.60 3.84 3.98
Glc
Gal
GlcNAc 4.38 3.76 3.56 4.03
Glc
Gal
GlcNAc 4.30 3.78 3.50 4.00
Glc
Gal
GlcNAc 4.24 3.77 3.48 3.96
Glc
Gal
GlcNAc 4.29 3.76 3.52 3.99
Glc
Gal
9.5
36bd
36cc
37
5.10 5.12 4.95 5.36
4.71 5.55 4.19 5.88
9.6
3.3
9.6
<1
4.6
4.8
3.6
4.93 4.96 3.90 5.02
4.77 5.52 4.38 5.93
9.5
3.0
7.3
9.7
3.4
6.6
9.4
3.2
9.4
<1
7.3
9.8
<1
6.6
9.7
<1
9.6
10.5
4.99 5.30 5.73 5.54
4.60 5.54 4.06 5.89
7.8
9.8
9.7
9.8
7.5
9.4
8.2
4.4
7.8
7.0
11.5
10.3
38c
5.13 5.21 5.73 5.35
4.79 5.53 4.40 5.97
7.8
4.05 10.0 10.0
5.0
3.5
10.0
3.49
4.24
4.04
3.41
4.43
3.86
3.37
4.19
4.01
3.47
4.15
4.29
3.43
4.45
4.17
3.32
4.21
4.30
3.39
8.5
7.8
8.0
8.6
8.2
8.3
10.0 10.0
8.8
3.0
39ac
39bc
39cc
40ac
40bc
40cc
5.00 5.06 4.88 5.21
4.72 5.53 4.31 5.93
<1
4.4
3.0
3.6
11.3
10.3 10.6
9.9
5.11 5.12 4.96 5.36
4.68 5.56 4.18 5.88
8.0
8.1
7.9
8.2
9.5
3.3
9.2
9.3
3.0
9.6
9.2
3.0
9.6
<1
9.2
9.4
<1
9.4
4.90 4.92 3.88 5.01
4.75 5.50 4.36 5.92
7.4
8.1
8.4
8.3
9.6
7.9
8.4
8.3
7.9
8.3
9.9
8.8
8.4
9.4
3.7
3.6
11.4
10.2
5.01 5.04 4.81 5.19
5.00 5.57 4.64 6.00
7.9
7.9
8.3
8.0
8.0
9.3
<1
8.0
GlcNAc 4.28 3.75 3.12 3.18
Glc
Gal
GlcNAc 4.28 3.72 3.57 3.59
Glc
Gal
5.10 5.12 4.90 5.32
4.95 5.59 4.48 5.93
9.5
3.2
9.2
9.6
3.0
9.6
<1
4.93 4.94 3.83 5.01
4.98 5.59 4.62 6.00
7.8
8.3
9.4
9.6
<1
3.9
7.9
GlcNAc 4.30 3.72 3.62 3.66
Note. Other signals: PhCH2 4.25—4.97 ppm (for all compounds except for 40a—b, 2a—c), NHAc 5.77 ppm (for compounds 3 and 4),
O(O)CCH3 1.88, 1.64 ppm (for compound 4), NHCOCH3 1.81—1.90 ppm (for all compounds except for 2a—c), NHCOCH3
2.02—2.08 ppm (for compounds 2a—c), OCH2CH2N 3.25—3.88 ppm (for all compounds except for 2a—c), OCH2CH2N
3.10—3.41 ppm (for all compounds except for 2a—c), OCH2CH2N 3.74—4.09 ppm (for compounds 2a—c), OCH2CH2N
2.94—3.28 ppm (for compounds 2a—c).
a The spectrum was recorded in D2O after preliminary deuterium exchange.
b Data for the αꢀanomer.
c The spectrum was recorded in CD3OD.
d The spectrum was recorded in a CDCl3—CD3OD solvent mixture, 2 : 0.4.
gives 2ꢀazidoethyl glycoside 18 in 89% yield. The formaꢀ
tion of product 18 was accompanied by disappearance of
the signal of the CH2Cl group in the 13C NMR spectrum,
which was replaced by the signal for CH2N3 (δ 50.6).
Compound 18 was then deacetylated and the triol 19
thus formed was made to react with benzaldehyde diꢀ
methyl acetal in the presence of TsOH to be converted
into 4,6ꢀOꢀbenzylidene derivative 20; the free hydroxy
group in 20 was benzylated by benzyl bromide in the
presence of sodium hydride in DMF16 to give benzyl
ether 21 in 83% yield. Then compound 21 was converted
into 3,6ꢀdiꢀOꢀbenzyl derivative 6 (yield 84%) by means of
Me3N•BH3/AlCl3ꢀinduced regioselective reductive cleavꢀ
age of the benzylidene ring in the presence of 2 equiv. of
water.16 The position of the free hydroxy group in comꢀ
pound 6 was confirmed by NOESY correlation between

Synthesis of oligosaccharides
Russ.Chem.Bull., Int.Ed., Vol. 56, No. 8, August, 2007
1659
Table 2. 13C NMR data for derivatives 2—4, 5b, 6, 10—13, 15, 17—18, 20—21, 25—27, 29, 30, 32—37, and 39—40 (CDCl3)
Comꢀ
pound
Residue
δ
Comꢀ
pound
Residue
δ
C(1) C(2) C(3) C(4) C(5) C(6)
C(1) C(2) C(3) C(4) C(5) C(6)
2aa
2ba
2ca
3
Glc
Gal
GlcNAc
Glc
Gal
GlcNAc
Glc
Gal
GlcNAc
Glc
Gal
GlcNAc
Glc
Gal
GlcNAc
Glc
Gal
GlcNAc
Glc
Glc
Glc
Glc
Glc
GlcNAc
GlcNAc
GlcNAc
GlcNAc
Glc
Glc
Gal
Glc
Gal
Glc
Gal
Glc
Gal
Glc
Gal
104.7 73.5 85.3 69.7
68.7
33
Glc
Gal
Glc
Gal
Glc
Gal
Glc
Gal
GlcNAc
Glc
Gal
GlcNAc
Glc
Gal
GlcNAc
Glc
Gal
GlcNAc
Glc
Gal
GlcNAc
Glc
Gal
GlcNAc
Glc
Gal
GlcNAc
Glc
Gal
GlcNAc
Glc
Gal
GlcNAc
Glc
101.2 71.8 72.1 69.2 72.0 62.0
90.6 71.0 73.8 71.2 67.4 63.1
101.2 71.7 72.1 69.0 72.1 62.1
93.7 69.3 73.9 70.2 70.3 63.1
101.1 71.7 72.1 69.0 72.0 61.9
83.9 69.6 78.5 70.4 75.7 63.2
102.5 74.0 79.3 71.3 74.3 68.0
101.5 73.4 77.8 73.0 73.0 64.4
102.4 55.8 81.1 77.2 75.8 68.9
102.8 73.7 79.0 71.0 72.9 64.0
101.5 72.8 79.8 71.9 73.1 64.1
102.5 55.9 81.2 77.2 75.7 68.8
102.7 75.7 73.8 73.3 74.5 68.5
101.5 73.6 77.7 72.9 72.9 64.1
102.4 55.9 81.2 77.2 75.9 68.9
101.5 71.8 72.6 69.4 72.3 62.8
99.6 71.5 77.6 69.8 71.8 62.3
100.2 53.9 77.6 75.0 74.7 68.5
102.5 73.9 79.2 71.3 74.2 68.0
101.4 73.3 77.9 72.9 72.9 64.3
102.5 55.7 81.2 77.0 75.6 68.7
102.7 73.7 79.1 70.9 72.8 63.9
101.5 73.0 79.8 71.9 72.9 64.1
102.5 55.8 81.2 77.1 75.6 68.7
102.6 75.1 73.8 73.4 74.5 68.7
101.3 73.9 77.9 73.0 73.0 64.2
102.5 55.8 81.2 77.1 75.7 68.8
102.6 73.9 79.4 71.4 74.1 68.1
102.6 72.7 77.6 73.2 73.5 64.7
102.5 56.4 73.7 81.4 76.0 61.1
102.6 73.6 79.3 70.9 73.0 64.0
102.4 72.1 79.6 72.0 73.4 64.3
102.5 56.3 73.5 81.2 75.8 60.9
102.7 75.6 74.0 73.3 74.4 68.5
102.7 72.9 77.2 73.2 73.7 64.7
102.7 56.3 73.6 81.7 76.0 61.1
103.9
83.8 76.2
102.5 56.4
104.8
34
85.5
104.1
83.6 69.9
35
102.4 56.3
104.9 74.4 76.7 70.5 74.8 68.4
103.7 71.2 83.5 69.5
36ad
102.4 56.3
101.7 74.7 73.7 71.4 75.1 61.3
99.6 71.1 79.1 70.2 71.4 61.9
100.2 54.0 77.6 75.0 74.8 68.6
101.2 71.6 72.0 69.0 72.1 62.0
99.6 71.4 77.2 69.9 71.8 62.5
100.2 54.2 77.7 75.0 74.7 68.4
101.2 71.7 72.2 69.1 72.0 62.0
100.0 70.1 78.1 76.1 66.7 68.9
100.2 56.1 80.9 72.4 74.1 70.3
99.9 69.7 73.1 72.1 74.2 65.7
99.1 69.5 69.6 70.6 73.9 65.4
89.2
36bd
36cc
37
4
5b
6
10
11
12
13b
15
17
18
20
21
25
26
39ac
39bc
39cc
40ac
40bc
40cc
90.3
93.3
101.0 54.7 72.2 68.7 72.0 62.1
100.5 54.9 72.1 68.6 71.9 62.0
100.9 57.5 70.8 81.5 66.2 68.5
100.2 58.2 76.2 82.9 66.0 68.8
83.8 70.5 73.6 69.3 76.1 62.7
101.2 71.8 72.4 69.3 72.2 75.9
82.7 72.7 76.6 75.8 62.4 68.9
97.4 72.7 68.7 68.3 67.2 63.3
82.7 74.5 73.6 74.5 69.9 69.3
101.6 71.0 72.9 68.5 71.8 61.8
99.8 70.5 78.3 75.9 66.8 69.0
101.0 71.7 72.1 69.0 72.0 61.9
99.8 71.2 77.4 69.9 71.8 63.0
101.0 71.7 72.1 69.0 72.0 61.9
99.8 71.2 77.4 69.9 71.8 63.0
27
29
30c
32
Gal
GlcNAc
Note. Other signals: PhCH2 73.2—75.1 ppm (for all compounds except for 40a—b), NHCOCH3 22.9—23.6 ppm, O(O)CCH3 20.6,
20.4 ppm (for compound 4), OCH2CH2N 67.8—69.3 ppm, OCH2CH2N 50.4—51.8 ppm (for compounds 3 and 4, 36 and 37),
OCH2CH2N 40.8—41.0 ppm (for compounds 39 and 40), OCH2CH2N 67.4—70.3 ppm (for compounds 2a—c), OCH2CH2N
40.5—41.1 ppm (for compounds 2a—c).
a The spectrum was recorded in D2O after preliminary deuterium exchange.
b Data for the αꢀanomer.
c The spectrum was recorded in CD3OD.
d The spectrum was recorded in a CDCl3—CD3OD solvent mixture, 2 : 0.4.
the H(3) and H(6) protons of glucosamine and the benꢀ
zylic methylene protons and the correlation between the
H(4) and 4ꢀOH protons.
Using the obtained monosaccharide derivatives, glucoꢀ
syl donors 14, 15, benzobromoglucose (22, model comꢀ
pound), and known acceptors 23 17 and 24,18 we started
the synthesis of the disaccharide block Glcβꢀ(1→3)ꢀGalβ
5 (Scheme 4). The 4,6ꢀOꢀbenzylidene group in galactoꢀ
sides 23 and 24 is expected to favor effective glycosylation
at position 3 (see Refs 17 and 19) compared, for example,
with the 4,6ꢀdiꢀOꢀbenzoyl structure.20,21 The presence of
the benzoyl group at the О(2) atom in derivatives of the

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Sukhova et al.
Scheme 3
Scheme 4
14: R1 = R2 = Ac, R3 = Br
23: R4 = SEt
24: R4 = OAll
15: R1 = R2 = Ac, R3 = OC(NH)CCl3
22: R1 = R2 = Bz, R3 = Br
5a: R1 = R2 = Bz, R4 = SEt; 5b: R1 = R2 = Ac, R4 = OAll
Reagents and conditions: i. Hg(CN)2/2ꢀchloroethanol (73%);
ii. NaN3, 18ꢀcrownꢀ6/DMF (89%); iii. 1 M MeONa/MeOH;
iv. PhCH(OMe)2, TsOH•H2O/DMF (85% over two steps);
v. BnBr, NaH/DMF (83%); vi. Me3N•BH3, AlCl3,
H2O/THF (84%).
The Helferich glycosylation of thiogalactoside 23 with
bromide 14 in the presence of molecular sieves AW300
affords thioglycoside 25, resulting from migration of the
ethylthio group to the glucosyl donor, in 93% yield. When
this reaction is promoted by silver triflate (in the presence
of molecular sieves either 4 Å or AW300), the initial acꢀ
ceptor 23, ethylthio group migration product 25, and
1,6ꢀlinked disaccharide 26, resulting from 4,6→3,4 miꢀ
gration of the benzylidene group in the acceptor followed
by glycosylation at the 6ꢀOH group liberated in the galacꢀ
tose residue, were isolated from the reaction mixture in
approximately equal yields. The NMR spectra of disacꢀ
charide 26 (see Table 1 and 2) exhibited signals (δH 5.91,
δC 105.3) nontypical of the PhCH fragment of sixꢀmemꢀ
bered acetals of the 1,3ꢀdioxane type (δH 5.5—5.6,
δC 100—101) but coinciding with those for fiveꢀmemꢀ
bered 1,3ꢀdioxolane structures.22 Glycosylation carried
out in the presence of symꢀcollidine for decreasing the
acidity and suppressing the migration of the benzylidene
group furnished disaccharide orthoseter 27 in 46% yield.
The structure of product 27 was confirmed by the
1H NMR spectrum, which contained a lowꢀfield signal
for H(1) of the αꢀglucose residue (δ 5.70, J1,2 = 5.0 Hz), a
highꢀfield signal for H(2) of the glucose residue (δ 4.49),
i.e., in the region of ring protons for which the correꢀ
sponding hydroxy group is not acylated. One more proof
was provided by the unusual values of the spinꢀspin couꢀ
pling constant (J1,2 = 5.0 Hz, J2,3 = 3.4 Hz, J3,4< 1 Hz),
which is a consequence of distortion of the 4C1 conformaꢀ
tion in the orthoester structure of 27. Note that in the
13C NMR spectrum, the chemical shift for C(1) of the
glucose residue (δ 97.4) attests to αꢀanomeric configuraꢀ
type 8 is required for the control of the stereochemical
outcome of glycosylation by disaccharide donors such
as 5 obtained from monosaccharide derivatives 7 and 8.
The allyl protective group chosen for the anomeric center
in galactoside 24 allows one to easily pass from allyl glyꢀ
coside 5 (R = OAll) to the reducing derivative 5 (R = OH)
and further to glycosyl donors of different types for subseꢀ
quent glycosylation. The use of thiogalactoside 23 as
the glycosyl acceptor leads directly to disaccharide glycoꢀ
syl donor 5 (R = SEt) without any additional transforꢀ
mations.
Our attempts to obtain the target disaccharide strucꢀ
tures by glycosylation of acceptors 23 and 24 with broꢀ
mide 14 and benzobromoglucose 22 failed. Thus the
Helferich condensation of bromide 22 with allyl glycoꢀ
side 24 (both in the presence and in the absence of moꢀ
lecular sieves 3 Å) and the silver triflateꢀinduced condenꢀ
sation in nitromethane yielded complex mixtures of unꢀ
identifiable products.
The reaction of bromide 22 with thioglycoside accepꢀ
tor 23 in the presence of silver triflate and molecular
sieves 4 Å also gave a complex mixture of products where
unconsumed acceptor 23 was the major component (reꢀ
covery ~40—60%). The largest yield of disaccharide 5a
was only ~15%; the βꢀconfiguration of the glycosidic bond
was confirmed by the characteristic J1,2 value of 7.5 Hz in
the 1H NMR spectrum.

Synthesis of oligosaccharides
Russ.Chem.Bull., Int.Ed., Vol. 56, No. 8, August, 2007
1661
this difficulty, we treated the reaction mixtures with acid
to remove the 4,6ꢀOꢀbenzylidene groups; the products
thus formed differed in chromatographic mobilities and
could easily be separated by chromatography. Thus, after
glycosylation of allyl glycoside 24 with donor 15 in the
presence of TMSOTf and molecular sieves AW300 in
CH2Cl2 and treatment of the reaction mixture with aqueꢀ
ous acetic acid, the disaccharide 4,6ꢀdiol 30 and 3,4,6ꢀ
triol 31 were isolated in 28 and 40% yield, respectively.
The best results of glycosylation of allyl glycoside 24
with imidate 15 were obtained when BF3•Et2O was used
as the promoter and the reaction was performed in
toluene. After removal of 4,6ꢀOꢀbenzylidene groups by
treatment with pyridinium pꢀtoluenesulfonate, disacchaꢀ
ride 4,6ꢀdiol 30 was isolated in 36% yield by chromatoꢀ
graphy.
The yield of disaccharide 5b was increased to 48%
when the product was isolated from the reaction mixture
by direct crystallization. The βꢀconfiguration of the glyꢀ
cosidic bond was confirmed by characteristic spinꢀspin
1
coupling constant J1,2, equal to 7.8 Hz, in the H NMR
spectrum.
The 4,6ꢀOꢀbenzylidene group in disaccharide 5b was
replaced by acidꢀresistant benzoate; to this end, comꢀ
pound 5b was treated with pyridinium pꢀtoluenesulfonate
in aqueous acetonitrile to give 4,6ꢀdiol 30 in 98% yield
(Scheme 5). Subsequent benzoylation of disaccharide 30
provided 4,6ꢀdiꢀOꢀbenzoyl derivative 32 in quantitative
yield. Removal of the allyl group in glycoside 32 upon
treatment with PdCl2/AcONa in 95% acetic acid24 furꢀ
nished reducing disaccharide 33 (yield 67%), which was
transformed into trichloroacetimidate 34 by the reaction
with CCl3CN in the presence of DBU10 (yield 73%).
The attempt at glycosylation of acceptor 6 with donor
34 in the presence of TMSOTf was unsuccessful; only
gradual destruction of the donor was observed, while acꢀ
ceptor 6 was recovered almost quantitatively from the
reaction mixture. Therefore, we tested thioglycoside 35,
which was prepared by reaction of imidate 34 with
ethanethiol in the presence of TMSOTf in 98% yield.
Glycosylation of acceptor 6 with thioglycoside 35 in
the presence of NIS/TfOH and molecular sieves AW300
in CH2Cl2 afforded the target trisaccharide 4 in 50% yield.
The presence of the βꢀbond between the galactopyranose
and glucosamine residues in trisaccharide 4 was confirmed
tion of this residue, whereas the corresponding signal for
substituted disaccharide derivatives Glcβꢀ(1→3)ꢀGalβ
would have been located at δ ≈ 100—101.
Imidate 15 was used as the glycosyl donor for the
synthesis of disaccharides of type 5, or, in model experiꢀ
ments, this was its tetraacetyl analog 28 (see Ref. 23). In
the reaction of trichloroacetimidate 28 with allyl glycoꢀ
side 24 in the presence of TMSOTf and molecular sieves
AW300 in CH2Cl2, the highest yield of disaccharide 29
was 36%. The βꢀconfiguration of the glycosidic bond in
disaccharide 29 was confirmed by the value of the couꢀ
pling constant J1,2 in the 1H NMR spectrum (7.8 Hz).
Note that glycosylation with trichloroacetimidates was
accompanied by fewer side processes than it was observed
in experiments with glucosyl bromides. The isolation of
reaction products 29 and 5b was difficult in both cases,
because disaccharides and the glycosyl acceptor 24 had
similar chromatographic mobilities. In order to overcome
by the corresponding spinꢀspin coupling constant J1,2
8.6 Hz in the 1H NMR spectrum.
=
On treatment with HCl in methanol,12 3″,6″ꢀdiꢀ
acetate 4 was converted into 3″,6″ꢀdiol 3 in 81% yield
(Scheme 6). The structure of diol 3 was confirmed by the
fact that the signals for the two acetyl groups disappeared
from the 1H and 13C NMR spectra and by the upfield
1
shifts of the H NMR signals for the protons H(3) and
H(6) of the glucopyranose ring (by 1.5 and ~0.6 ppm,
respectively).

1662
Russ.Chem.Bull., Int.Ed., Vol. 56, No. 8, August, 2007
Sukhova et al.
Scheme 5
was prepared in 79% yield by selective 6ꢀsulfation of
3″,6″ꢀdiol 3 with complex SO3•Py at reduced temperaꢀ
ture.25 The position of the sulfate group in product 36c
followed from the downfield shifts observed in the 1H and
13C NMR spectra for H(6) (by ~0.5 ppm) and C(6)
(by 7 ppm) of the glucose residue with respect to those in
the starting diol 3. Meanwhile, the chemical shifts of the
H(3) signals in 1H NMR spectrum and the C(3) signals in
the 13C NMR spectrum have remained almost unchanged.
This indicates that the OH group at C(3) was not involved
in the reaction. Complete sulfation of diol 3 with SO3•Py
(see Ref. 26) resulted in disulfate 36a in 86% yield. The
structure of disulfated trisaccharide 36a was confirmed by
characteristic downfield shift of the signals for the H(3)
and H(6) protons of the glucose residue (see Table 1).
The 13C NMR signals for C(3) and C(6) atoms of the
glucopyranose residue also shifted downfield by 6 and
7 ppm, respectively.
For the synthesis of 3″ꢀsulfated trisaccharide derivaꢀ
tive 3, it was necessary first to protect the more reactive
primary hydroxy group (see Scheme 6). For this purꢀ
pose, diol 3 was monobenzoylated with benzoyl cyanide
(1.2 equiv.) in the presence of Et3N at room temperaꢀ
ture.27 The reaction was moderately regioselective and
resulted in a mixture containing monoꢀ and dibenzoylated
products along with the starting compound 3. Due to
similar chromatographic mobilities of these compounds,
they were not subjected to product separation. Instead,
the reaction mixture obtained upon benzoylation was subꢀ
jected to complete sulfation with an excess of SO3•Py. As
a result, fully benzoylated trisaccharide 37, disulfate 36a,
and the products of monobenzoylation−monosulfation of
diol 3, namely, compounds 36b and 38, were isolated.
Reagents and conditions: i. PPTS/90% aq. CH3CN (98%);
ii. BzCl/pyridine (99%); iii. PdCl2, AcONa/95% aq. AcOH
(67%); iv. CCl3CN,DBU/CH2Cl2 (73%); v. EtSH,
TMSOTf/CH2Cl2, MS 4 Å (98%); vi. 6, NIS, TfOH/CH2Cl2,
MS AW300 (50%).
Diol 3 served as the starting compound in the syntheꢀ
sis of three target sulfated trisaccharides, viz., 3″,6″ꢀdisulꢀ
fate 2a, 3″ꢀsulfate 2b, and 6″ꢀsulfate 2c. Compound 36c
Scheme 6
Reagents and conditions: i. AcCl/MeOH (81%; ii. SO3•Py/DMF (86%); iii. BzCN, Et3N/CH3CN; iv. SO3•Py/DMF (45% over two
steps); v. SO3•Py/pyridine (80%).

Synthesis of oligosaccharides
Russ.Chem.Bull., Int.Ed., Vol. 56, No. 8, August, 2007
1663
The presence of polar sulfate groups in products 36a,b
and 38 increased essentially the difference between their
chromatographic mobilities both compared with 3,6ꢀdiꢀ
benzoate 37 and between each other, which facilitated
the separation. Thus, product 37 was isolated in 10% yield,
disulfate 36a, in 32% yield, and 3ꢀsulfated trisaccharide
36b, in 45% yield (see Scheme 6).
prevents effective hydrogenolysis of benzyl groups,11 the
reduction products were treated with ethyl trifluoroacetate
to give trifluoroacetamides 39a—c in 62—83% yield. The
13C NMR spectra of compounds 39a—c displayed a charꢀ
acteristic change in the chemical shift of the signal for the
methylene group of the spacer (δ 50—52 → 40—41),
which
corresponds
to
the
transformation
The position of the sulfate group in isomeric monoꢀ
sulfates—monobenzoates 36b and 38 was established based
on the combination of 1H and 13C NMR data. Benꢀ
zoylation and sulfation induce similar downfield shifts of
the corresponding proton signals of the glucose residue in
the 1H NMR spectra with respect to those in unsubstituted
derivatives. At the same time, a comparison of the data
for diol 3, 3,6ꢀdibenzoate 37, and 3,6ꢀdisulfate 36a (see
Table 1) shows that benzoylation induces a greater shift
than sulfation. A comparison of the shifts of the signals
for H(3) and H(6a,b) for monosulfates 36b and 38 sugꢀ
gests that 36b is sulfated at position 3, and 38, at posiꢀ
tion 6. However, a more reliable proof for the structure of
monosulfate 36b comes from 13C NMR data, because the
sulfate group, unlike the benzoyl group, has a pronounced
αꢀeffect (5—7 ppm) (see Table 2).
CH2N3 → CH2NHCOCF3.
Subsequent removal of the benzyl groups in derivaꢀ
tives 39a—c by hydrogenolysis was accompanied by
partial desulfation. The optimization of the reaction conꢀ
ditions for each substrate allowed us to obtain deꢀ
benzylation products 40a—c in 44—83% yields. In the
final step of the preparation of the target compounds, the
benzoyl and Nꢀtrifluoroacetyl groups were removed by
treatment with an alkali, and the target sulfated trisacchaꢀ
rides 2a—c were isolated by gel chromatography on
Sephadex Gꢀ15. The presence and the positions of the
sulfate groups in compounds 2a—c were confirmed by
characteristic downfield shifts of the corresponding proꢀ
ton and carbon signals in the H and 13C NMR spectra
(see Tables 1 and 2).
Thus, we carried out the first synthesis of 2ꢀaminoethyl
glycosides of 6ꢀsulfoꢀmimetic of the natural HNKꢀ1 antiꢀ
genic trisaccharide and the corresponding monosulfated
derivatives.
1
The azide group in compounds 36a—c was conꢀ
verted into the amino group by catalytic hydrogenation
(Scheme 7). Since the presence of free amino groups
Scheme 7
R1 = R2 = SO3Na (36a, 39a, 40a); R1 = Bz, R2 = SO3Na (36b, 39b, 40b); R1 = SO3Na, R2 = H (36c, 39c, 40c)
Reagents and conditions: i. H2, 10% yield Pd(OH)2/C, AcOH/MeOH; ii. CF3CO2Et, Et3N/MeOH (62—83% yield over two steps);
iii. H2, 10% yield PdO/C, AcOH/MeOH (44—83% yield); iv. 1 M MeONa/MeOH; v. 1M NaOH/H2O (94—99% yield over two
steps).

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Sukhova et al.
(light petroleum—ethyl acetate, 2 : 1). Found (%): C, 60.56;
H, 5.16. C26H26O11. Calculated (%): C, 60.70; H, 5.09.
1H NMR (δ: 8.10—7.12 (m, 10 H, 2Ph); 2.21, 2.08, 1.89 (three s,
9 H, 3 CH3C(O)O). 13C NMR, δ: 21—20 (three signals,
3 CH3C(O)O).
Experimental
Commercial Fluka, Acros, and Merck chemicals were used.
The methods for solvent and reagent purification, conditions for
recording the NMR spectra and determination of physicochemiꢀ
cal parameters were described previously.28,29 All 2D correlaꢀ
tion NMR experiments were carried out by standard Bruker
procedures. The MALDIꢀTOF mass spectra were recorded on a
Microflex Bruker Daltonics instrument. The optical rotation
of solutions of the compounds obtained was measured in chloꢀ
roform (c = 1) on a PUꢀ07 digital polarimeter (Russia) at
19—21 °C. Thin layer chromatography was carried out on plates
with silica gel Kieselgelꢀ60 (Merck), the compounds were deꢀ
tected by spraying with a 10% (v/v) solution of orthophosphoric
acid in ethyl alcohol with subsequent heating at ~150 °C. Colꢀ
umn chromatography was carried out on silica gel Kiesegel 60
(Merck, 230—400 mesh). Melting points were determined of a
Koffler hot stage. Gel chromatography was carried out on
a 38×3 cm column with Sephadex Gꢀ15 gel using water as the
eluent (flow rate 1.5 mL min–1). Hydrogenolysis was performed
under atmospheric pressure and 20 °C.
3,6ꢀDiꢀOꢀacetylꢀ2,4ꢀdiꢀOꢀbenzoylꢀDꢀglucopyranose (13).
The salt N2H4•HOAc (225 mg, 2.44 mmol) was added at 4 °C to
a solution of triacetate 12 (505 mg, 0.98 mmol) in DMF (7 mL).
The mixture was kept for 2 h at room temperature, diluted with
EtOAc (60 mL), and washed with water (3×50 mL). The orꢀ
ganic layer was separated, dried with MgSO4, and concentrated.
Column chromatography of the residue (toluene—ethyl acetate,
3 : 1) gave hemiacetal 13 as a mixture of α,βꢀanomers in ~1 : 1
ratio. Yield 409 mg (88%), amorphous, [α]D +36, Rf 0.23; 0.29
(toluene—ethyl acetate, 4 : 1). Found (%): C, 60.82; H, 5.28.
C
24H24O10. Calculated (%): C, 61.01; H, 5.12. 1H NMR, δ:
8.10—7.40 (m, 10 H, 2 Ph); 3.95, 3.19 (both d, 2 H, 1ꢀOH
for β and α anomers, respectively); 2.05, 1.87 (both s, 6 H,
2 CH3C(O)O).
3,6ꢀDiꢀOꢀacetylꢀ2,4ꢀdiꢀOꢀbenzoylꢀαꢀDꢀglucopyranosyl broꢀ
mide (14). A 33% solution of HBr in AcOH (3.0 mL) and acetic
anhydride (0.15 mL) were added at 4 °C to a solution of triꢀ
acetate 12 (334 mg, 0.65 mmol) in CH2Cl2 (2.5 mL). The mixꢀ
ture was kept for 18 h at 4 °C, diluted with CHCl3 (50 mL), and
washed with ice water (3×30 mL) and a saturated solution of
NaHCO3 (3×30 mL). The organic layer was separated, the solꢀ
vent was evaporated, and the residue was dried in vacuo to give
bromide 14. Yield 344 mg (99%), foam, [α]D +212 (c 0.5,
CHCl3), Rf 0.52 (toluene—ethyl acetate, 8 : 1). 1H NMR, δ:
8.10—7.45 (m, 10 H, 2 Ph); 2.05, 1.85 (both s, 6 H, 2 CH3COO).
3,6ꢀDiꢀOꢀacetylꢀ2,4ꢀdiꢀOꢀbenzoylꢀαꢀDꢀglucopyranosyl triꢀ
chloroacetimidate (15). Trichloroacetonitrile (7.62 mL,
75.99 mmol) was added under dry argon to a solution of hemiꢀ
acetal (3.6 g, 7.63 mmol) 13 in CH2Cl2 (68 mL). Then 1,8ꢀdiꢀ
azabicyclo[5.4.0]undecꢀ7ꢀene (1.45 mL, 9.54 mmol) was added
at 4 °C. After the reaction mixture has warmed to room temꢀ
perature (2 h), chromatography in the toluene—ethyl acetate
system (9 : 1) containing 1% (v/v) Et3N was carried out to give
trichloroacetimidate 15. Yield 3.81 g (81%), foam, [α]D +60,
Rf 0.32 (toluene—ethyl acetate, 9 : 1). 1H NMR, δ: 8.75 (s, 1 H,
OC(NH)CCl3); 8.12—7.12 (m, 10 H, 2 Ph); 2.12, 1.75 (both s,
6 H, 2 CH3C(O)O).
2ꢀChloroethyl 2ꢀacetamidoꢀ3,4,6ꢀtriꢀOꢀacetylꢀ2ꢀdeoxyꢀβꢀDꢀ
glucopyranoside (17). A suspension of chloride 16 (see Ref. 20)
(5.0 g, 13.70 mmol) and Hg(CN)2 (6.93 g, 27.43 mmol) in
2ꢀchloroethanol (14 mL) was heated at 60 °C until the promoter
completely dissolved (3 h). The reaction mixture was concenꢀ
trated, the residue was dissolved in chloroform (100 mL), the
precipitated mercury salts were filtered off through a celite bed,
the filtrate was washed successively with a 1 M solution of KBr,
a saturated aqueous solution of NaHCO3, and water, the orꢀ
ganic layer was separated, and the solvent was evaporated.
The residue was recrystallized from isopropyl alcohol to give
chloroethyl glycoside 17. Yield 4.14 g (73% yield), m.p. 143 °C,
[α]D –16 (c 0.5, CH3OH), Rf 0.28 (toluene—acetone, 7 : 4).
Found (%): C, 46.76; H, 5.72; N, 3.68. C16H24ClNO9. Calcuꢀ
lated (%): C, 46.89; H, 5.90; N, 3.42. 1H NMR, δ: 5.77 (d, 1 H,
NHAs, J2,NHAc = 8.7 Hz); 4.19—3.60 (m, 4 H, OCH2CH2Cl);
2.11—1.92 (four s, 12 H, 4 CH3C(O)). 13C NMR, δ: 69.7
(OCH2CH2Cl); 42.9 (OCH2CH2Cl); 23.4 (CH3C(O)N);
20.7—20.8 (three signals, 3 CH3C(O)O).
1H and 13C NMR data for the pyranose ring signals in the
synthesized compounds are summarized in Tables 1 and 2.
1,6ꢀAnhydroꢀ2,4ꢀdiꢀOꢀbenzoylꢀβꢀDꢀglucopyranose (10). Benꢀ
zoyl chloride (7.5 mL, 65.12 mmol) was added dropwise at 4 °C
to a solution of 1,6ꢀanhydroꢀβꢀDꢀglucopyranose 9 (5.25 g,
32.38 mmol) in pyridine (25 mL) and the reaction mixture was
kept for 2 h at the same temperature, diluted with CHCl3
(100 mL), and washed with 1M H2SO4 (3×50 mL), water
(3×50 mL), and saturated solution of NaHCO3 (3×50 mL). The
organic layer was separated and concentrated. Column chromaꢀ
tography (ethyl acetate—light petroleum, 12 : 5) gave dibenꢀ
zoate 10. Yield 4.89 g (40%), white crystals, [α]D –34 (lit.13
:
[α]D –34), Rf 0.10 (toluene—ethyl acetate, 10 : 1), m.p. 130 °C
(lit.13: m.p. 128—129 °C). Found (%): C, 64.60; H, 4.76.
C
20H18O7. Calculated (%): C, 64.86; H, 4.90. 1H NMR, δ:
8.10—7.10 (m, 10 H, 2Ph); 3.33 (d, 1 H, 3ꢀOH, J3,OH = 5.3 Hz).
1,6ꢀAnhydroꢀ3ꢀOꢀacetylꢀ2,4ꢀdiꢀOꢀbenzoylꢀβꢀDꢀglucopyraꢀ
nose (11). Dibenzoyl derivative 10 (3.8 g, 10.26 mmol) was
acetylated with acetic anhydride (4.9 mL, 52 mmol) in pyridine
(8.5 mL) at room temperature for 24 h. The mixture was conꢀ
centrated, the residue was dissolved in toluene, and the solvent
was evaporated (3×5 mL). The residue was crystallized from an
ethyl acetate—light petroleum mixture; subsequent column chroꢀ
matography of the mother liquor (toluene—ethyl acetate, 25 : 1)
gave additional amount of acetate 11. Overall yield 4.06 g
(96% yield), m.p. 125 °C, [α]D –35, Rf 0.35 (toluene—ethyl
acetate, 10 : 1). Found (%): C, 64.18; H, 4.60. C22H20O8. Calꢀ
culated (%): C, 64.07; H, 4.89. 1H NMR, δ: 8.12—7.48 (m,
10 H, 2 Ph); 2.12 (s, 3 H, CH3C(O)O).
1,3,6ꢀTriꢀOꢀacetylꢀ2,4ꢀdiꢀOꢀbenzoylꢀαꢀDꢀglucopyranose
(12). Concentrated H2SO4 (0.25 mL, 4.69 mmol) was added
dropwise at 4 °C to a solution of derivative 11 (4.0 g, 9.70 mmol)
in Ac2O (35 mL). The reaction mixture was kept for 18 h at the
same temperature and poured onto ice (200 mL). The mixture
was stirred for 2 h and extracted with chloroform (2×100 mL).
The extract was washed with water (2×100 mL) and a cold
saturated solution of NaHCO3 (2×100 mL) and concentrated,
the residue was dissolved in toluene, the solvent was evaporated
(4×20 mL), and the residue was dried in vacuo to give triꢀ
acetate 12. Yield 4.97 g (98%), amorphous, [α]D +57, Rf 0.33

Synthesis of oligosaccharides
Russ.Chem.Bull., Int.Ed., Vol. 56, No. 8, August, 2007
1665
2ꢀAzidoethyl 2ꢀacetamidoꢀ3,4,6ꢀtriꢀOꢀacetylꢀ2ꢀdeoxyꢀβꢀ
Dꢀglucopyranoside (18). 2ꢀChloroethyl derivative 17 (4.1 g,
10.00 mmol) was dissolved in anhydrous DMF (65 mL), then
NaN3 (13.2 g, 0.20 mol) and 18ꢀcrownꢀ6 (264 mg, 1.00 mmol)
were added. The mixture was stirred for 36 h at 70 °C, diluted
with EtOAc (200 mL), and washed with water (3×200 mL). The
organic layer was concentrated and the residue was dried in a
waterꢀjet pump vacuum to give 2ꢀazidoethyl glycoside 18, yield
3.70 g (89%), m.p. 149 °C, [α]D –30, Rf 0.29 (toluene—acetone,
7 : 4). Found (%): C, 45.87; H, 5.65; N, 13.68. C16H24N4O9.
13C NMR, δ: 101.3 (PhCH < O); 74.7 (OCH2Ph); 68.8
(OCH2CH2N3); 50.7 (OCH2CH2N3); 23.7 (CH3C(O)N).
2ꢀAzidoethylꢀ2ꢀacetamidoꢀ3,6ꢀdiꢀOꢀbenzylꢀ2ꢀdeoxyꢀβꢀDꢀ
glucopyranoside (6). Anhydrous AlCl3 (350 mg, 2.62 mmol) was
added at 4 °C under dry argon to a solution of 4,6ꢀOꢀbenꢀ
zylidene derivative 21 (205 mg, 0.44 mmol) and Me3N•BH3
(127 mg, 1.74 mmol) in anhydrous THF (7 mL). After complete
dissolution of aluminum chloride, water (15.8 µL, 0.88 mmol)
was added. The mixture was stirred for 12 h at 20 °C, diluted
with EtOAc (50 mL), and washed successively with 1 M HCl
(40 mL), brine (40 mL), and water (40 mL), and the organic
layer was dried and concentrated. The residue was recrystallized
from isopropyl alcohol to give 3,6ꢀdiꢀOꢀbenzyl derivative 6. Yield
173 mg (84%), m.p. 243 °C, [α]D –17 (c 1, CH3OH), Rf 0.25
(toluene—acetone, 20 : 6). Found (%): C, 60.97; H, 6.23;
N, 11.74. C24H30N4O6. Calculated (%): C, 61.26; H, 6.43;
N, 11.91. 1H NMR, δ: 7.45—7.20 (m, 10 H, 2 Ph); 5.73 (d, 1 H,
NHAs, J2,NHAc = 7.6 Hz); 4.84—4.78 (both d, 2 H, CH2Ph,
1
Calculated (%): C, 46.15; H, 5.81; N, 13.46. H NMR, δ: 5.60
(d, 1 H, NHAs, J2,NHAc = 8.6 Hz); 4.08—3.64 (m, 2 H,
OCH2CH2N3); 3.51—3.22 (m, 2 H, OCH2CH2N3); 2.08—1.92
(four s, 12 H, 4 CH3C(O)). 13C NMR, δ: 68.4 (OCH2CH2N3);
50.6 (OCH2CH2N3); 23.4 (CH3C(O)N); 20.8—20.6 (three sigꢀ
nals, 3 CH3C(O)O).
2ꢀAzidoethyl 2ꢀacetamidoꢀ4,6ꢀOꢀbenzylideneꢀ2ꢀdeoxyꢀβꢀ
Dꢀglucopyranoside (20). A 1 M solution of sodium methoxide in
methanol (0.9 mL) was added to a solution of 2ꢀazidoethyl
glycoside 18 (3.7 g, 8.89 mmol) in anhydrous MeOH (12 mL).
After 3 h, the mixture was deionized by the cation exchange
resin KUꢀ2 (H+), the resin was filtered off and washed with
methanol, and the filtrate was concentrated to give 2.47 g of
triol 19. α,αꢀDimethoxytoluene (2.56 mL, 17 mmol) was added
to a solution of triol 19 (2.47 g, 8.51 mmol) and TsOH•H2O
(81 mg, 0.43 mmol) in anhydrous DMF (14 mL), and the mixꢀ
ture was stirred for 5 h at 60 °C and neutralized with Et3N
(120 µL, 0.86 mmol). The reaction mixture was diluted
with CH2Cl2 (150 mL) and washed with water (3×100 mL),
and the organic layer was concentrated. Column chromatoꢀ
graphy of the residue (chloroform—methanol, 40 : 1.2) gave
4,6ꢀOꢀbenzylidene derivative 20. Yield 2.86 g (85% yield), m.p.
239 °C, [α]D –92 (c 0.5, CH3OH), Rf 0.48 (chloroform—methaꢀ
nol, 40 : 1.2). Found (%): C, 53.94; H, 5.91; N, 14.68.
Jgem = 11.7 Hz); 4.65—4.53 (both d, 2 H, CH2Ph, Jgem
=
12.1 Hz); 4.11—3.63 (m, 2 H, OCH2CH2N3); 3.53—3.19 (m,
2 H, OCH2CH2N3); 2.80 (d, 1 H, 4ꢀOH, J4,OH < 1 Hz); 1.85 (s,
3 H, CH3C(O)N). 13C NMR (δ: 74.6, 73.6 (2 OCH2Ph); 68.1
(OCH2CH2N3); 50.6 (OCH2CH2N3); 23.6 (CH3C(O)N).
Glycosylation of ethyl thiogalactoside 23 with glucosyl broꢀ
mide 22. A mixture of ethylthio derivative 23 (29 mg, 69 µmol),
glucosyl bromide 22 (70 mg, 97 µmol), and molecular sieves
MS 4 Å (170 mg) in anhydrous CH2Cl2 (2 mL) was stirred for
2 h under dry argon and cooled to –22 °C. A solution of AgOTf
(37 mg, 0.14 mmol) in anhydrous toluene (0.5 mL) was added.
The reaction mixture was heated to 0 °C over a period of 2 h.
Then pyridine (0.1 mL) was added and the mixture was diluted
with chloroform (80 mL), filtered through a celite bed, and
washed successively with a saturated aqueous solution of
Na2S2O3 (80 mL) and water (80 mL). The organic layer was
concentrated, the residue was dissolved in toluene, and the solꢀ
vent was evaporated. The residue was chromatographed in a
toluene—ethyl acetate system (8 : 1) to give 16 mg (55%) of the
starting glycosyl acceptor 23 and 10 mg (15%) of disacchaꢀ
ride 5a, amorphous, Rf 0.28 (toluene—acetone, 15 : 1).
C
17H22N4O6. Calculated (%): C, 53.96; H, 5.86; N, 14.81.
1H NMR, δ: 7.48—7.26 (m, 5 H, Ph); 5.49 (s, 1 H, PhCH<O);
3.98—3.58 (m, 2 H, OCH2CH2N3); 3.47—3.19 (m, 2 H,
OCH2CH2N3); 1.93 (s, 3 H, CH3C(O)N). 13C NMR, δ: 101.7
(PhCH < O); 68.3 (OCH2CH2N3); 50.6 (OCH2CH2N3); 22.9
(CH3C(O)N).
Glycosylation of ethyl thiogalactoside 23 with glucosyl broꢀ
mide 14. A (in the presence of molecular sieves 4 Å and AgOTf ).
Under the conditions of glycosylation of ethyl thiogalactoside
23 with glucosyl bromide 22, derivative 23 (15 mg, 36 µmol) was
made to react with glucosyl bromide 14 (25 mg (47 µmol) in
anhydrous CH2Cl2 (2 mL) in the presence of molecular sieves
MS 4 Å (220 mg) and AgOTf (20.5 mg, 80 µmol) in anhydrous
toluene (0.5 mL). Chromatography in a toluene—ethyl acetate
system (8 : 1) gave 5 mg (33%) of the starting acceptor 23 (amorꢀ
phous, Rf 0.21 (toluene—acetone, 7 : 1)), 6 mg (32%) of the
ethylthio group migration product 25 (amorphous, Rf 0.50 (toluꢀ
ene—acetone, 7 : 1)), and 8 mg (26%) of 1,6ꢀbound disacchaꢀ
ride 26 (amorphous, Rf 0.42 (toluene—acetone, 7 : 1)). 1H NMR
(25), δ: 8.09—7.42 (m, 10 H, 2 Ph); 2.76 (m, 2 H, SCH2CH3);
2.02, 1.81 (both s, 6 H, 2 CH3C(O)O); 1.29 (t, 3 H, SCH2CH3).
13C NMR, δ: 29.6 (SCH2CH3); 20.6, 20.4 (two signals,
2ꢀAzidoethyl 2ꢀacetamidoꢀ3ꢀOꢀbenzylꢀ4,6ꢀOꢀbenzylideneꢀ2ꢀ
deoxyꢀβꢀDꢀglucopyranoside (21). A mixture of 4,6ꢀOꢀbenzylidene
derivative 20 (2.75 g, 7.28 mmol) and a 60% mineral oil suspenꢀ
sion of NaH (814 mg, 20.30 mmol) in anhydrous DMF (35 mL)
was cooled to –20 °C, and benzyl bromide (0.96 mL, 8.03 mmol)
was added with stirring. The cooling bath was removed and,
after warmingꢀup to room temperature, the reaction mixture
was stirred for 1 h. Then the mixture was cooled to –40 °C and
acetic acid (1.95 mL) was added. After warmingꢀup to room
temperature, the reaction mixture was diluted with CH2Cl2
(150 mL) and washed with water and saturated aqueous solution
of NaHCO3, and the organic layer was dried and concentrated.
Crystallization of the residue from an ethyl acetate—light petroꢀ
leum mixture gave 3ꢀOꢀbenzyl derivative 21. Yield 2.84 g (83%),
m.p. 242 °C, [α]D –71 (c 0.5, CH3OH), Rf 0.20 (toluene—ethyl
acetate, 3 : 2). Found (%): C, 61.32; H, 5.81; N, 11.81.
C24H28N4O6. Calculated (%): C, 61.53; H, 6.02; N, 11.96.
1H NMR, δ: 7.51—7.23 (m, 10 H, 2 Ph); 5.63 (d, 1 H, NHAs,
J2,NHAc = 7.3 Hz); 5.57 (s, 1 H, PhCH<O); 4.88—4.63 (2d, 2 H,
CH2Ph, Jgem = 11.7 Hz); 4.04—3.68 (m, 2 H, OCH2CH2N3);
3.48—3.23 (m, 2 H, OCH2CH2N3); 1.89 (s, 3 H, CH3C(O)N).
1
2 CH3C(O)O); 14.8 (SCH2CH3). H NMR (26), δ: 8.15—7.10
(m, 20 H,
4 Ph); 5.91 (s, 1 H, PhCH<O); 2.45 (m,
2 H, SCH2CH3); 2.01, 1.79 (both s, 6 H, 2 CH3C(O)O); 1.05
(t, 3 H, SCH2CH3). 13C NMR, δ: 105.2 (PhCH<O); 24.0
(SCH2CH3); 20.6, 20.4 (two signals, 2 CH3C(O)O); 14.7
(SCH2CH3).

1666
Russ.Chem.Bull., Int.Ed., Vol. 56, No. 8, August, 2007
Sukhova et al.
B (in the presence of molecular sieves AW300 and AgOTf ).
Glycosylation of derivative 23 (28 mg, 67 µmol) with glucosyl
bromide 14 (50 mg, 93 µmol) in anhydrous CH2Cl2 (2 mL) in
the presence of molecular sieves AW300 (200 mg) and AgOTf
(35 mg, 136 µmol) in anhydrous toluene (0.5 mL) under aboveꢀ
described conditions gave, after chromatography, 12 mg (42%)
of the starting acceptor 23, 8 mg (23%) of ethylthio group transꢀ
fer product 25, and 15 mg (25%) of 1,6ꢀbound disaccharide 26.
C (in the presence of molecular sieves 4 Å, AgOTf, and symꢀ
collidine). A mixture of ethylthio derivative 23 (28.7 mg,
68.9 µmol), glucosyl bromide 14 (51.6 mg, 96.5 µmol), and
molecular sieves MS 4 Å (170 mg) in anhydrous CH2Cl2 (2 mL)
was stirred for 2 h under dry argon and cooled to –22 °C. symꢀ
Collidine (15 µL, 0.11 mmol) and, 5 min later, a solution of
AgOTf (37.1 mg, 0.14 mmol) in anhydrous toluene (0.5 mL)
were added. The reaction mixture was heated to 0 °C over a
period of 2 h and worked up as described above. Chromatoꢀ
graphy in a toluene—acetone system (15 : 1) gave orthoester 27.
Yield 27.7 mg (46% yield), amorphous. Rf 0.19 (toluene—acꢀ
etone, 15 : 1). 1H NMR, δ: 8.03—7.24 (m, 20 H, 4 Ph); 5.36 (s,
1 H, PhCH<O); 2.90—2.71 (m, 2 H, SCH2CH3); 1.99, 1.91
(both s, 6 H, 2 CH3C(O)O); 1.37 (t, 3 H, SCH2CH3). 13C NMR,
δ: 101.1 (PhCH<O); 22.7 (SCH2CH3); 20.6, 20.6 (two signals,
2 CH3C(O)O); 14.8 (SCH2CH3).
D (in the presence of molecular sieves AW300, Hg(CN)2,, and
HgBr2). A mixture of ethylthio derivative 23 (31 mg, 75 µmol),
glucosyl bromide 14 (59 mg, 110 µmol), and molecular sieves
AW 300 (200 mg) in anhydrous CH2Cl2 (4 mL) was stirred for
2 h under dry argon, and Hg(CN)2 (37 mg, 0.14 mmol) and
HgBr2 (37 mg, 0.14 mmol) were added. The reaction mixture
was stirred for 12 h, diluted with chloroform (80 mL), and
filtered through a celite bed. The filtrate was washed succesꢀ
sively with a saturated aqueous solution of NaBr + NaHCO3
(1 : 1) (80 mL) and water (80 mL). The organic layer was conꢀ
centrated, the residue was dissolved in toluene, and the solvent
was evaporated. Chromatography in a toluene—acetone system
(15 : 1) gave the product of ethylthio group migration to glycosyl
acceptor 25. Yield 36 mg (93%).
Allyl (2,3,4,6ꢀtetraꢀOꢀacetylꢀβꢀDꢀglucopyranosyl)ꢀ(1→3)ꢀ
4,6ꢀOꢀbenzylideneꢀ2ꢀOꢀbenzoylꢀβꢀDꢀgalactopyranoside (29). Anꢀ
hydrous CH2Cl2 (2 mL) was added under dry argon to a mixture
of allyl galactoside 24 (62 mg, 0.15 mmol), trichloroacetimidate
28 (74 mg, 0.15 mmol), and molecular sieves AW300 (210 mg),
the mixture was stirred for 1 h at 20 °C and cooled to –20 °C,
and TMSOTf (3 µL, 17 µmol) was added. The reaction mixture
was stirred for 1 h at –20 °C and heated to 10 °C over a period of
1.5 h, Et3N (50 µL) was added, and the mixture was stirred
for 10 min, filtered through a celite bed, and washed with
dichloromethane (80 mL). The filtrate was washed with a satuꢀ
rated aqueous solution of NaHCO3 (80 mL) and water (80 mL).
The organic layer was filtered through a cotton wool bed and
concentrated. The residue was chromatographed in an ethyl
acetate—light petroleum system (1 : 1) to give disaccharide 29.
Yield 40 mg (36%), amorphous, Rf 0.30 (ethyl acetate—light
petroleum, 3 : 1). 1H NMR, δ: 8.05—7.30 (m, 10 H, 2 Ph);
5.28—5.18 (m, 1 H, OCH2CH=CH2); 5.55 (s, 1 H, PhCH<O);
5.15—5.01 (both dd, 2 H, OCH2CH=CH2); 4.33—4.10 (both d,
2 H, OCH2CH=CH2); 2.01, 1.98, 1.89, 1.52 (four s, 12 H,
4 CH3C(O)O). 13C NMR, δ: 100.8 (PhCH<O).
argon to a mixture of allyl galactoside 24 (18 mg, 44 µmol),
trichloroacetimidate 15 (33 mg, 53 µmol), and molecular sieves
AW300 (100 mg), the mixture was stirred for 1 h at 20 °C and
cooled to –20 °C, and TMSOTf (1 µL, 6 µmol) was added. The
reaction mixture was stirred for 2 h at –20 °C and for 12 h at
–10 °C, and heated to 10 °C over a period of 1.5 h. Triethylꢀ
amine (50 µL) was added, and the mixture was stirred for 10 min,
filtered through a celite bed, and washed with dichloromethane
(80 mL). The filtrate was washed with a saturated aqueous soluꢀ
tion of NaHCO3 (80 mL) and water (80 mL). The organic layer
was filtered through a cotton wool layer and concentrated to a
volume of ~5 mL, 75% aqueous AcOH (4 mL) was added, and
the mixture was stirred for 4 h at 80 °C. The organic layer was
concentrated, the residue was dissolved in toluene, and the solꢀ
vent was evaporated. The residue was chromatographed in an
ethyl acetate—light petroleum system (7 : 3) to give 9.5 mg of
disaccharide 4,6ꢀdiol 30 (28%, amorphous, Rf 0.30 (ethyl acꢀ
etate—light petroleum, 7 : 3)) and 5.7 mg of 3,4,6ꢀtriol 31 (40%,
amorphous, Rf 0.08 (ethyl acetate—light petroleum, 7 : 3)).
Glycosylation of allyl galactoside 24 with trichloroacetꢀ
imidate 28. Anhydrous toluene (5 mL) was added under dry
argon to a mixture of allyl galactoside 24 (40 mg, 97 µmol),
trichloroacetimidate 28 (84 mg, 136 µmol), and molecular sieves
AW300 (500 mg), the mixture was stirred for 1 h at 20 °C and
cooled to 0 °C, and BF3•Et2O (10 µL, 80 µmol) was added. The
reaction mixture was stirred for 2 h at 0 °C and for 48 h at
–10 °C. The temperature was raised to 10 °C over a period of
2.5 h, and the mixture was diluted with CH2Cl2 (5 mL), stirred
for 10 min, filtered through a celite bed, and washed with a
dichloromethane—ethyl acetate mixture (3 : 1) (2×50 mL). The
filtrate was concentrated without heating, and the residue was
diluted with chloroform (50 mL) and washed with a saturated
aqueous solution of NaHCO3 (2×50 mL) and water (50 mL).
The organic layer was concentrated and the residue was dried
in vacuo. The residue was dissolved in 90% aq. CH3CN (3 mL),
and Py•TsOH (20 mg, 80 µmol) was added. The mixture was
stirred for 4 h at 80 °C, concentrated without heating, diluted
with chloroform (50 mL), and washed with a saturated aqueous
solution of NaHCO3 (2×50 mL) and water (50 mL). The orꢀ
ganic layer was concentrated. The residue was chromatographed
in a toluene—ethyl acetate system (10 : 3) to give 27.2 mg of
disaccharide 4,6ꢀdiol 30 (36%).
Allyl (3,6ꢀdiꢀOꢀacetylꢀ2,4ꢀdiꢀOꢀbenzoylꢀβꢀDꢀglucopyranoꢀ
syl)ꢀ(1→3)ꢀ4,6ꢀOꢀbenzylideneꢀ2ꢀOꢀbenzoylꢀβꢀDꢀgalactopyranoꢀ
side (5b). Molecular sieves AW300 (800 mg) were added unꢀ
der dry argon to a solution of allyl galactoside 24 (116 mg,
0.28 mmol) and trichloroacetimidate 15 (174 mg, 0.28 mmol) in
anhydrous toluene (8 mL), the mixture was stirred for 1 h at
20 °C and cooled to 0 °C, and BF3•Et2O (21.3 µL, 0.17 mmol)
was added. The reaction mixture was stirred for 48 h at 4 °C. The
temperature was raised to 10 °C over a period of 2.5 h, and the
mixture was diluted with dichloromethane (5 mL), stirred for
10 min, filtered through a celite bed, and washed with a
dichloromethane—ethyl acetate mixture (3 : 1) (2×80 mL). The
filtrate was concentrated without heating, diluted with chloroꢀ
form (100 mL), and washed with a saturated aqueous solution of
NaHCO3 (2×80 mL) and water (80 mL). The organic layer was
concentrated. Crystallization of the residue from an ethyl acꢀ
etate—light petroleum mixture gave disaccharide 5b. Yield
121 mg (48%), m.p. 251 °C, [α]D +10, Rf 0.38 (toluene—acꢀ
etone, 20 : 6). Found (%): C, 65.12; H, 5.48. C47H46O16. Calcuꢀ
Glycosylation of allyl galactoside 24 with trichloroacetꢀ
imidate 15. Anhydrous CH2Cl2 (1 mL) was added under dry

Synthesis of oligosaccharides
Russ.Chem.Bull., Int.Ed., Vol. 56, No. 8, August, 2007
1667
1
lated (%): C, 65.12; H, 5.35. H NMR, δ: 7.95—7.13 (m, 20 H,
imidate (34). Trichloroacetonitrile (1.16 mL, 11.62 mmol) and
1,8ꢀdiazabicyclo[5.4.0]undecꢀ7ꢀene (0.22 mL, 1.45 mmol) were
added at 4 °C under dry argon to a solution of hemiacetal 33
(1.10 g, 1.16 mmol) in anhydrous dichloromethane (6 mL).
Over a period of 2 h, the temperature of the reaction mixture
was raised to 20 °C. Chromatography in the ethyl acetate—light
petroleum system (2 : 1.5) containing 1% (v/v) of triethylamine
gave trichloroacetimidate 34. Yield 931 mg (73%), foam,
[α]D +50, Rf 0.42 (ethyl acetate—light petroleum, 1 : 1).
1H NMR, δ: 8.49 (s, 1 H, OC(NH)CCl3); 8.11—7.06 (m, 25 H,
5 Ph); 1.99, 1.68 (both s, 6 H, 2 CH3C(O)O). 13C NMR, δ: 20.6,
20.2 (two signals, 2 CH3C(O)O).
Ethyl (3,6ꢀdiꢀOꢀacetylꢀ2,4ꢀdiꢀOꢀbenzoylꢀβꢀDꢀglucopyraꢀ
nosyl)ꢀ(1→3)ꢀ2,4,6ꢀtriꢀOꢀbenzoylꢀ1ꢀthioꢀβꢀDꢀgalactopyranoside
(35). Molecular sieves 4 Å (500 mg) and ethanethiol (105 µL,
1.42 mmol) were added under dry argon to a solution of
trichloroacetimidate 34 (913 mg, 0.84 mmol) in anhydrous
CH2Cl2 (5 mL). The mixture was stirred for 40 min and cooled
to 4 °C, and TMSOTf (53 µL, 0.29 mmol) was added. The
reaction mixture was stirred for 2 h, filtered through a celite bed,
and washed with CH2Cl2 (80 mL). The filtrate was washed with
a saturated aqueous solution of NaHCO3 and water and the
solvent was evaporated. Column chromatography in a light peꢀ
troleum—ethyl acetate system (2 : 1.3) gave thioglycoside 35.
Yield 815 mg (98%), m.p. 84 °C, [α]D +12, Rf 0.33 (light petroꢀ
leum—ethyl acetate, 2 : 1.5). Found (%): C, 64.00; H, 5.30.
C53H50O17S. Calculated (%): C, 64.23; H, 5.09. 1H NMR, δ:
8.12—7.13 (m, 25 H, 5 Ph); 2.76—2.61 (m, 2 H, SCH2CH3);
1.91, 1.64 (both s, 6 H, 2 CH3C(O)O); 1.18 (t, 3 H, SCH2CH3).
13C NMR, δ: 24.1 (SCH2CH3); 20.5, 20.2 (two signals,
2 CH3C(O)O); 14.8 (SCH2CH3).
2ꢀAzidoethyl (3,6ꢀdiꢀOꢀacetylꢀ2,4ꢀdiꢀOꢀbenzoylꢀβꢀDꢀglucoꢀ
pyranosyl)ꢀ(1→3)ꢀ(2,4,6ꢀtriꢀOꢀbenzoylꢀβꢀDꢀgalactopyranosyl)ꢀ
(1→4)ꢀ2ꢀacetamidoꢀ3,6ꢀdiꢀOꢀbenzylꢀ2ꢀdeoxyꢀβꢀDꢀglucopyranoꢀ
side (4). A mixture of thioglycoside 35 (50 mg, 0.05 mmol),
acceptor 6 (15 mg, 0.03 mmol), and molecular sieves AW300
(300 mg) in anhydrous CH2Cl2 (3 mL) was stirred under dry
argon for 40 min and cooled to –25 °C. NꢀIodosuccinimide
(16 mg, 0.06 mmol) and, 5 min later, trifluoromethanesulfonic
acid (7 µL, 0.08 mmol) were added. The reaction mixture was
stirred for 2.5 h with gradual temperature rise to –10 °C, and
then pyridine (0.8 mL) was added. The mixture was diluted with
dichloromethane (80 mL) and filtered through a celite bed, the
filtrate was washed successively with a 1 M solution of Na2S2O3
(80 mL) and a saturated aqueous solution of NaHCO3 (80 mL).
The organic layer was concentrated and the residue was chroꢀ
matographed in a light petroleum—ethyl acetate system (1 : 2)
to give trisaccharide 4. Yield 22 mg (50%), m.p. 77 °C, [α]D –14,
Rf 0.23 (light petroleum—ethyl acetate, 1 : 2). Found (%):
C, 64.32; H, 5.16; N, 4.22. C75H74N4O23. Calculated (%):
C, 64.37; H, 5.33; N, 4.00.
2ꢀAzidoethyl (2,4ꢀdiꢀOꢀbenzoylꢀβꢀDꢀglucopyranosyl)ꢀ(1→3)ꢀ
(2,4,6ꢀtriꢀOꢀbenzoylꢀβꢀDꢀgalactopyranosyl)ꢀ(1→4)ꢀ2ꢀacetꢀ
amidoꢀ3,6ꢀdiꢀOꢀbenzylꢀ2ꢀdeoxyꢀβꢀDꢀglucopyranoside (3). A soꢀ
lution of HCl in MeOH (5.2 mL, prepared by adding 0.2 mL of
acetyl chloride to 5 mL of anhydrous MeOH at 0—5 °C) was
added to trisaccharide 4 (747 mg, 0.53 mmol). The mixture was
stirred for 16 h at 4 °C, diluted with CH2Cl2 (100 mL), and
washed with a saturated aqueous solution of NaCl + NaHCO3
(1 : 1) (100 mL). The organic layer was concentrated. Chromaꢀ
tography of the residue in a chloroform—methanol system
4 Ph); 5.71—5.62 (m, 1 H, OCH2CH=CH2); 5.51 (s, 1 H,
PhCH<O); 5.14—4.97 (two dd,
4.28—4.13 (both d, 2 H, OCH2CH=CH2); 1.92, 1.70 (both s,
6 H, 2 CH3C(O)O). 13C NMR, δ: 129.7 (OCH2CH=CH2);
2 H, OCH2CH=CH2);
117.0
(OCH2CH=CH2);
100.8
(PhCH<O);
68.9
(OCH2CH=CH2); 20.6, 20.3 (two signals, 2 CH3C(O)O).
Allyl (3,6ꢀdiꢀOꢀacetylꢀ2,4ꢀdiꢀOꢀbenzoylꢀβꢀDꢀglucopyraꢀ
nosyl)ꢀ(1→3)ꢀ2ꢀOꢀbenzoylꢀβꢀDꢀgalactopyranoside (30). Salt
Py•TsOH (946 mg, 3.77 mmol) was added to a solution
of 4,6ꢀOꢀbenzylidene derivative 5b (1.75 g, 1.98 mmol) in
90% aq. acetonitrile (170 mL) and the reaction mixture was
stirred at 80 °C for 36 h and concentrated. The diol derivative
was extracted from the aqueous phase with dichloromethane
(3×80 mL). The extract was concentrated and the residue was
dried in an oil pump vacuum. The yield of disaccharide 30 was
1.51 g (98%), syrup, [α]D +3, Rf 0.27 (toluene—acetone, 2 : 1).
Found (%): C, 61.53; H, 5.42. C40H42O16. Calculated (%):
C, 61.69; H, 5.44. 1H NMR, δ: 7.95—7.13 (m, 20 H, 4 Ph);
5.71—5.62 (m, 1 H, OCH2CH=CH2); 5.51 (s, 1 H, PhCH<O);
5.14—4.97 (two dd, 2 H, OCH2CH=CH2); 4.28—4.13 (both d,
2 H, OCH2CH=CH2); 1.92, 1.70 (both s, 6 H, 2 CH3C(O)O).
13C NMR, δ: 129.7 (OCH2CH=CH2); 117.0 (OCH2CH=CH2);
100.8 (PhCH<O); 68.9 (OCH2CH=CH2); 20.6, 20.3 (two sigꢀ
nals, 2CH3C(O)O).
Allyl (3,6ꢀdiꢀOꢀacetylꢀ2,4ꢀdiꢀOꢀbenzoylꢀβꢀDꢀglucopyranoꢀ
syl)ꢀ(1→3)ꢀ2,4,6ꢀtriꢀOꢀbenzoylꢀβꢀDꢀgalactopyranoside (32).
Benzoyl chloride (1.38 mL, 11.90 mmol) was added at –10 °C to
a solution of diol 30 (1.54 g, 1.98 mmol) in pyridine (15 mL),
the mixture was stirred for 3 h at room temperature, diluted with
dichloromethane (100 mL), washed successively with 1 M HCl
(80 mL), water (80 mL), and a saturated aqueous solution of
NaHCO3 (80 mL), and the solvent was evaporated. Column
chromatography (gradient elution with light petroleum—ethyl
acetate (2 : 1) → ethyl acetate) gave benzoylated product 32.
Yield 1.95 g (99%), amorphous, [α]D +16, Rf 0.33 (light petroꢀ
leum—ethyl acetate, 1 : 0.8). Found (%): C, 65.74; H, 5.08.
54H50O18. Calculated (%): C, 65.71; H, 5.11. 1H NMR,
δ: 8.13—7.13 (m, 25 H, Ph); 5.70—5.61 (m, H,
OCH2CH=CH2); 5.09—4.96 (both dd, 2 H, OCH2CH=CH2);
4.27—4.03 (both d, 2 H, OCH2CH=CH2); 1.91, 1.63 (both s,
6 H, 2 CH3C(O)O). 13C NMR, δ: 132.7 (OCH2CH=CH2);
117.6 (OCH2CH=CH2); 69.7 (OCH2CH=CH2); 20.5, 20.2 (two
signals, 2 CH3C(O)O).
(3,6ꢀDiꢀOꢀacetylꢀ2,4ꢀdiꢀOꢀbenzoylꢀβꢀDꢀglucopyranosyl)ꢀ
(1→3)ꢀ2,4,6ꢀtriꢀOꢀbenzoylꢀβꢀDꢀgalactopyranose (33). A suspenꢀ
sion of allyl glycoside 32 (2.06 g, 2.09 mmol), palladium chloꢀ
ride (422 mg, 2.38 mmol), and sodium acetate (414 mg,
5.05 mmol) in 95% aq. acetic acid (40 mL) was heated for 3 h
at 70 °C. The reaction mixture was diluted with chloroform
(70 mL) and filtered through celite, and the filtrate was concenꢀ
trated. The residue was dissolved in toluene and the solvent was
evaporated. Column chromatography (light petroleum—ethyl
acetate, 2 : 1) gave hemiacetal 33. Yield 1.33 g (67%), amorꢀ
phous, [α]D +33, Rf 0.30 (light petroleum—ethyl acetate, 2 : 1.5).
Found (%): C, 64.42; H, 5.08. C51H46O18. Calculated (%):
C, 64.69; H, 4.90. 1H NMR, δ: 8.10—6.99 (m, 25 H, 5 Ph);
1.92, 1.62 (both s, 6 H, 2 CH3C(O)O). 13C NMR (δ: 20.7, 20.3
(two signals, 2 CH3C(O)O).
C
5
1
(3,6ꢀDiꢀOꢀacetylꢀ2,4ꢀdiꢀOꢀbenzoylꢀβꢀDꢀglucopyranosyl)ꢀ
(1→3)ꢀ2,4,6ꢀtriꢀOꢀbenzoylꢀDꢀgalactopyranosyl trichloroacetꢀ

1668
Russ.Chem.Bull., Int.Ed., Vol. 56, No. 8, August, 2007
Sukhova et al.
(20 : 1) gave diol 3. Yield 571 mg (81%), amorphous, [α]D –15,
Rf 0.19 (ethyl acetate—light petroleum, 2 : 1). Found (%):
C, 64.96; H, 5.62; N, 4.31. C71H70N4O21. Calculated (%):
C, 64.83; H, 5.36; N, 4.26.
(2 mL) was added. The mixture was stirred for 20 min and
filtered, the resin was washed with methanol (10 mL), and the
filtrate was concentrated. Chromatography of the residue in a
chloroform—methanol system (10 : 1) gave 6ꢀsulfated prodꢀ
uct 36c. Yield 18 mg (79%), amorphous, [α]D –14 (c 1, CH3OH),
Rf 0.19 (chloroform—methanol, 10 : 1). MALDIꢀTOFꢀMS, calꢀ
culated for [C71H69N4NaO24S + Na]+: 1440.4. Found: 1440.1.
Calculated for [C71H69N4NaO24S + K]+: 1456.4. Found: 1456.1.
Disodium salt of 2ꢀtrifluoroacetamidoethyl (2,4ꢀdiꢀOꢀbenzoylꢀ
3,6ꢀdiꢀOꢀsulfoꢀβꢀDꢀglucopyranosyl)ꢀ(1→3)ꢀ(2,4,6ꢀtriꢀOꢀ
benzoylꢀβꢀDꢀgalactopyranosyl)ꢀ(1→4)ꢀ2ꢀacetamidoꢀ3,6ꢀdiꢀOꢀ
benzylꢀ2ꢀdeoxyꢀβꢀDꢀglucopyranoside (39a). 3,6ꢀDisulfate 36a
(54 mg, 35 µmol) in anhydrous MeOH (2 mL) was hydrogeꢀ
nated for 1 h in a hydrogen atmosphere in the presence of acetic
acid (10 µL) and 10% Pd(OH)2/C (30 mg). The reaction mixꢀ
ture was filtered through a celite bed, which was then washed
with methanol (30 mL) and the combined filtrates were concenꢀ
trated. The residue was dissolved in anhydrous methanol
(3.8 mL), and ethyl trifluoroacetate (25 µL, 0.21 mmol) and
triethylamine (20 µL, 0.14 mmol) were added. After 3 h, a
MeOH—H2O mixture (3 : 1) (2 mL) and cation exchange resin
Amberlite IRꢀ120 (Na+) (2 mL) were added. The reaction mixꢀ
ture was stirred for 20 min and filtered, the resin was washed
with methanol (10 mL), and the filtrate was concentrated. Chroꢀ
matography of the residue in a chloroform—methanol system
(5 : 1) gave Nꢀtrifluoroacetylated product 39a. Yield 47 mg
(83%), amorphous, [α]D –9 (c 1, CH3OH), Rf 0.32 (chloroꢀ
form—methanol, 10 : 3). MALDIꢀTOFꢀMS, calculated for
[C73H69F3N2Na2O28S2 + Na]+: 1612.4. Found: 1611.7. Calcuꢀ
lated for [C73H69F3N2Na2O28S2 + K]+: 1628.4. Found: 1627.7.
Sodium salt of 2ꢀtrifluoroacetamidoethyl (2,4,6ꢀtriꢀOꢀbenꢀ
zoylꢀ3ꢀOꢀsulfoꢀβꢀDꢀglucopyranosyl)ꢀ(1→3)ꢀ(2,4,6ꢀtriꢀOꢀbenꢀ
zoylꢀβꢀDꢀgalactopyranosyl)ꢀ(1→4)ꢀ2ꢀacetamidoꢀ3,6ꢀdiꢀOꢀbenꢀ
zylꢀ2ꢀdeoxyꢀβꢀDꢀglucopyranoside (39b). 3ꢀSulfate 36b (42 mg,
28 µmol) was hydrogenated in a similar way. The product
was converted into Nꢀtrifluoroacetate 39b, which was isolated in
a chloroform—methanol system (10 : 1), yield 36 mg (81%),
amorphous, [α]D +4 (c 1, CH3OH), Rf 0.40 (chloroꢀ
form—methanol, 5 : 1). MALDIꢀTOFꢀMS, calculated for
[C80H74F3N2NaO26S + Na]+: 1614.5. Found: 1614.4. Calcuꢀ
lated for [C80H74F3N2NaO26S + K]+: 1630.5. Found: 1630.4.
Sodium salt of 2ꢀtrifluoroacetamidoethyl (2,4ꢀdiꢀOꢀbenzoylꢀ
6ꢀOꢀsulfoꢀβꢀDꢀglucopyranosyl)ꢀ(1→3)ꢀ(2,4,6ꢀtriꢀOꢀbenzoylꢀβꢀDꢀ
galactopyranosyl)ꢀ(1→4)ꢀ2ꢀacetamidoꢀ3,6ꢀdiꢀOꢀbenzylꢀ2ꢀdeoxyꢀ
βꢀDꢀglucopyranoside (39c). A similar procedure for 6ꢀsulfate 36c
(24 mg, 17 µmol) gave Nꢀtrifluoroacetate 39s, yield 16 mg (63%),
amorphous, [α]D –12 (c 0.5, CH3OH), Rf 0.21 (chloroꢀ
form—methanol, 5 : 3). MALDIꢀTOFꢀMS, calculated for
[C59H58F3N2NaO25S + Na]+: 1510.4. Found: 1510.1. Calcuꢀ
lated for [C59H58F3N2NaO25S + K]+: 1526.4. Found: 1526.1.
Disodium salt of 2ꢀtrifluoroacetamidoethyl (2,4ꢀdiꢀOꢀbenzoylꢀ
3,6ꢀdiꢀOꢀsulfoꢀβꢀDꢀglucopyranosyl)ꢀ(1→3)ꢀ(2,4,6ꢀtriꢀOꢀbenꢀ
zoylꢀβꢀDꢀgalactopyranosyl)ꢀ(1→4)ꢀ2ꢀacetamidoꢀ2ꢀdeoxyꢀβꢀDꢀ
glucopyranoside (40a). 3,6ꢀDisulfate 39a (21 mg, 13 µmol) was
hydrogenated in anhydrous MeOH (2 mL) for 40 h in the presꢀ
ence of acetic acid (10 µL) and 10% PdO/C (15 mg). The
reaction mixture was filtered through a celite bed, which was
then washed with methanol (30 mL). The filtrate was concenꢀ
trated, chromatography of the residue in a chloroform—methaꢀ
nol system (5 : 1) gave debenzylated product 40a. Yield 15 mg
(83%), amorphous, [α]D +5 (c 1, CH3OH), Rf 0.32
Disodium salt of 2ꢀazidoethyl (2,4ꢀdiꢀOꢀbenzoylꢀ3,6ꢀdiꢀOꢀ
sulfoꢀβꢀDꢀglucopyranosyl)ꢀ(1→3)ꢀ(2,4,6ꢀtriꢀOꢀbenzoylꢀβꢀDꢀ
galactopyranosyl)ꢀ(1→4)ꢀ2ꢀacetamidoꢀ3,6ꢀdiꢀOꢀbenzylꢀ2ꢀdeoxyꢀ
βꢀDꢀglucopyranoside (36a). The complex SO3•Py (60 mg,
0.38 mmol) was added to a solution of 3,6ꢀdiol 3 (50 mg, 38 µmol)
in DMF (1 mL), the reaction mixture was stirred for 1.5 h at
20 °C, then NaHCO3 (54 mg, 0.64 mmol) was added, and the
mixture was stirred for 1 h and filtered. The precipitate was
washed on the filter with methanol (10 mL) and the filtrate was
concentrated. The residue was dissolved in aq. MeOH (10 : 1)
(5 mL) and the cation exchange resin Amberlite IRꢀ120 (Na+)
(2 mL) was added. The mixture was stirred for 20 min and
filtered, the resin was washed with methanol (10 mL), and the
filtrate was concentrated. Chromatography of the residue in a
chloroform—methanol system (10 : 1) gave disulfate 36a. Yield
49 mg (86%), amorphous, [α]D +5 (c 1, CH3OH), Rf 0.28 (chloꢀ
roform—methanol, 20 : 1.8). MALDIꢀTOFꢀMS, calculated for
[C71H68N4Na2O27S2 + Na]+: 1542.4. Found: 1542.2. Calcuꢀ
lated for [C71H68N4Na2O27S2 + K]+: 1558.4. Found: 1558.2.
Sodium salt of 2ꢀazidoethyl (2,4,6ꢀtriꢀOꢀbenzoylꢀ3ꢀOꢀsulfoꢀ
βꢀDꢀglucopyranosyl)ꢀ(1→3)ꢀ(2,4,6ꢀtriꢀOꢀbenzoylꢀβꢀDꢀgalactoꢀ
pyranosyl)ꢀ(1→4)ꢀ2ꢀacetamidoꢀ3,6ꢀdiꢀOꢀbenzylꢀ2ꢀdeoxyꢀβꢀDꢀ
glucopyranoside (36b). Benzoyl cyanide (17 mg, 0.13 mmol) and
triethylamine (15 µL, 0.11 mmol) were added to a solution of
3,6ꢀdiol 3 (141 mg, 0.11 mmol) in anhydrous CH3CN (4 mL).
The mixture was stirred for 12 h at 20 °C, methanol (7 mL) was
added, and 15 min later, the solvent was evaporated to dryness.
The residue was dissolved in DMF (3 mL) and the complex
SO3•Py (119 mg, 0.75 mmol) was added. The reaction mixture
was stirred for 3 h at 20 °C, NaHCO3 (128 mg, 1.78 mmol) was
added, and the mixture was stirred for 1 h and filtered. The
precipitate was washed with methanol (10 mL) and the filtrate
was concentrated. The residue was dissolved in a MeOH—H2O
mixture (10 : 1) (5.5 mL) and the cation exchange resin
Amberlite IRꢀ120 (Na+) (2 mL) was added. The mixture was
stirred for 20 min and filtered, the resin was washed with methaꢀ
nol (10 mL), and the filtrate was concentrated. Chromatography
of the residue in a chloroform—methanol system (20 : 1) gave
73 mg (45%) of 3ꢀsulfated product 36b; the other isolated
products included 16 mg (10%) of fully benzoylated prodꢀ
uct 37, 13 mg of a mixture of 3ꢀsulfate 36b and 6ꢀsulfate 38, and
54 mg (32%) of disulfated product 36a. Data for 3ꢀsulfate 36b:
amorphous, [α]D +4 (c 1, CH3OH), Rf 0.49 (chloroꢀ
form—methanol, 5 : 1). MALDIꢀTOFꢀMS, calculated for
[C78H73N4NaO25S + Na]+: 1544.5. Found: 1544.4. Calculated
for [C78H73N4NaO25S + K]+: 1560.5. Found: 1560.4.
Sodium salt of 2ꢀazidoethyl (2,4ꢀdiꢀOꢀbenzoylꢀ6ꢀOꢀsulfoꢀβꢀ
Dꢀglucopyranosyl)ꢀ(1→3)ꢀ(2,4,6ꢀtriꢀOꢀbenzoylꢀβꢀDꢀgalactoꢀ
pyranosyl)ꢀ(1→4)ꢀ2ꢀacetamidoꢀ3,6ꢀdiꢀOꢀbenzylꢀ2ꢀdeoxyꢀβꢀDꢀ
glucopyranoside (36c). The complex SO3•Py (7.6 mg, 48 µmol)
was added with ice cooling to a solution of 3,6ꢀdiol 3 (21 mg,
16 µmol) in pyridine (1.5 mL). The reaction mixture was stirred
for 12 h at 4 °C, NaHCO3 (6.8 mg, 94 µmol) was added, and the
mixture was stirred for 1 h and filtered. The precipitate was
washed with methanol (10 mL) and the filtrate was evaporated.
The residue was dissolved in a MeOH—H2O mixture (10 : 1)
(5.5 mL) and the cation exchange resin Amberlite IRꢀ120 (Na+)

Synthesis of oligosaccharides
Russ.Chem.Bull., Int.Ed., Vol. 56, No. 8, August, 2007
1669
(chloroform—methanol, 10 : 3). MALDIꢀTOFꢀMS, calculated
for [C59H57F3N2Na2O28S2 + Na]+: 1432.2. Found: 1432.2.
Calculated for [C59H57F3N2Na2O28S2
Found: 1448.1.
N,Oꢀdeacetylated as described for derivative 40a. Gel chromaꢀ
tography on a column with Sephadex Gꢀ15 in water followed by
freeze drying gave 6ꢀsulfated trisaccharide 2c. Yield 16 mg
(94%), amorphous, [α]D –10 (c 1, water), Rf 0.52 (acetoꢀ
nitrile—water—methanol—butanol—propanol—0.1 N HCl,
+
K]+: 1448.2.
Sodium salt of 2ꢀtrifluoroacetamidoethyl (2,4,6ꢀtriꢀOꢀbenꢀ
zoylꢀ3ꢀOꢀsulfoꢀβꢀDꢀglucopyranosyl)ꢀ(1→3)ꢀ(2,4,6ꢀtriꢀOꢀbenꢀ
zoylꢀβꢀDꢀgalactopyranosyl)ꢀ(1→4)ꢀ2ꢀacetamidoꢀ2ꢀdeoxyꢀβꢀDꢀ
glucopyranoside (40b). 3ꢀSulfate 39b (13 mg, 8 µmol) was hydroꢀ
genated in anhydrous methanol (1 mL) for 5 h in the presence
of acetic acid (5 µL) and 10% PdO/C (26 mg). The reaction
mixture was filtered through a celite bed, which was then
washed with methanol (30 mL). The filtrate was concenꢀ
trated, chromatography of the residue in a chloroform—methaꢀ
nol system (10 : 1) gave debenzylated product 40b. Yield
5 mg (44%), amorphous, [α]D +18 (c 0.5, CH3OH), Rf 0.37
(chloroform—methanol, 5 : 1). MALDIꢀTOFꢀMS, calcuꢀ
lated for [C66H62F3N2NaO26S + Na]+: 1434.3. Found: 1434.0.
1 : 1 : 1 : 1 : 2 : 1).
MALDIꢀTOFꢀMS,
calculated
for
[C22H39N2NaO19S + Na]+: 713.6. Found: 713.3. Calculated for
[C22H39N2NaO19S + K]+: 729.6. Found: 729.3.
The authors are grateful to A.S. Shashkov and A. A.
Grachev (Institute of Organic Chemistry, Russian Acadꢀ
emy of Sciences) for recording NMR spectra.
References
1. A. V. Kornilov, E. V. Sukhova, and N. E. Nifantiev,
Carbohydr. Res., 2001, 336, 309.
2. R. Kleene and M. Schachner, Nat. Rev. Neurosci.,
2004, 5, 195.
Calculated for [C66H62F3N2NaO26
Found: 1450.0.
S
+
K]+: 1450.3.
Sodium salt of 2ꢀtrifluoroacetamidoethyl (2,4ꢀdiꢀOꢀbenzoylꢀ
6ꢀOꢀsulfoꢀβꢀDꢀglucopyranosyl)ꢀ(1→3)ꢀ(2,4,6ꢀtriꢀOꢀbenzoylꢀβꢀ
Dꢀgalactopyranosyl)ꢀ(1→4)ꢀ2ꢀacetamidoꢀ2ꢀdeoxyꢀβꢀDꢀglucoꢀ
pyranoside (40c). 6ꢀSulfate 39c (16 mg, 11 µmol) was hydrogeꢀ
nated in anhydrous methanol (2 mL) for 12 h in the presence of
acetic acid (10 µL) and 10% PdO/C (16 mg). The reaction
mixture was filtered through a celite bed, which was then washed
with methanol (30 mL).The filtrate was concentrated, chromaꢀ
tography of the residue in a chloroform—methanol system
(10 : 1) gave debenzylated product 40c. Yield 8 mg (56%), amorꢀ
phous, [α]D +4 (c 0.5, CH3OH), Rf 0.40 (chloroform—methaꢀ
nol, 10 : 1).
Disodium salt of 2ꢀaminoethyl (3,6ꢀdiꢀOꢀsulfoꢀβꢀDꢀglucoꢀ
pyranosyl)ꢀ(1→3)ꢀβꢀDꢀgalactopyranosylꢀ(1→4)ꢀ2ꢀacetamidoꢀ2ꢀ
deoxyꢀβꢀDꢀglucopyranoside (2a). A 1 M solution of sodium
methoxide in methanol (0.16 mL) was added to a solution of
trisaccharide 40a (22 mg, 15 µmol) in methanol (1.5 mL) and
the mixture was stirred for 18 h. A 1 M aqueous solution of
NaOH (100 µL) was added and the mixture was stirred for 24 h,
neutralized by acetic acid (15 µL, 0.25 mmol), and concenꢀ
trated. Gel chromatography on a column with Sephadex Gꢀ15
in water followed by freeze drying gave 12 mg (96%) of 3,6ꢀdiꢀ
sulfated trisaccharide 2a, amorphous, [α]D –5 (c 0.5, water),
Rf 0.43 (acetonitrile—water—methanol—butanol—proꢀ
panol—0.1 N HCl, 1 : 1 : 1 : 1 : 2 : 1). MALDIꢀTOFꢀMS,
calculated for [C22H38N2Na2O22S2 + Na]+: 815.6. Found:
815.1. Calculated for [C22H38N2Na2O22S2 + K]+: 831.6.
Found: 831.1.
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Sodium salt of 2ꢀaminoethyl (3ꢀOꢀsulfoꢀβꢀDꢀglucopyranosyl)ꢀ
(1→3)ꢀβꢀDꢀgalactopyranosyl)ꢀ(1→4)ꢀ2ꢀacetamidoꢀ2ꢀdeoxyꢀβꢀDꢀ
glucopyranoside (2b). Trisaccharide 40b (19 mg, 13 µmol) was
N,Oꢀdeacetylated as described for derivative 40a. Gel chroꢀ
matography on a column with Sephadex Gꢀ15 in water folꢀ
lowed by freeze drying gave 9 mg (99%) of 3ꢀsulfated trisacchaꢀ
ride 2b, amorphous, [α]D –5 (c 0.5, water), Rf 0.43 (acetoꢀ
nitrile—water—methanol—butanol—propanol—0.1 M HCl,
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1 : 1 : 1 : 1 : 2 : 1).
MALDIꢀTOFꢀMS,
calculated
for
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[C22H39N2NaO19S + Na]+: 713.6. Found: 714.3. Calculated for
[C22H39N2NaO19S + K]+: 729.6. Found: 730.2.
Sodium salt of 2ꢀaminoethyl (6ꢀOꢀsulfoꢀβꢀDꢀglucopyranosyl)ꢀ
(1→3)ꢀβꢀDꢀgalactopyranosylꢀ(1→4)ꢀ2ꢀacetamidoꢀ2ꢀdeoxyꢀβꢀDꢀ
glucopyranoside (2c). Trisaccharide 40c (32 mg, 25 µmol) was

1670
Russ.Chem.Bull., Int.Ed., Vol. 56, No. 8, August, 2007
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Received June 21, 2007;
in revised form July 23, 2007