Reactivity of the Hydroxy Groups in Melezitose and Their Selective Protection

Article abstract of DOI:10.1023/A:1025593715104

The reactivity of melezitose hydroxy groups was studied by tritylation in pyridine with subsequent acetylation. After partial detritylation of the products, acetyl group transfer from position 4 to 6 was observed. The structure of the prepared melezitose

Full text of DOI:10.1023/A:1025593715104

Russian Journal of Organic Chemistry, Vol. 39, No. 3, 2003, pp. 384 391. Translated from Zhurnal Organicheskoi Khimii, Vol. 39, No. 3, 2003,
pp. 415 421.
Original Russian Text Copyright
2003 by Tsao, Dou, Sun’, Lyu, Koroteev, Krasnov.
Reactivity of the Hydroxy Groups in Melezitose
and Their Selective Protection
L. Tsao1, Kh. Dou1, G. Sun’2, Yu. Lyu1, A. M. Koroteev3, and G. B. Krasnov3
1
Faculty of Chemistry, Sinjiang University, Urumqi, China
2
Faculty of Chemistry, Tianjin Medical University, Tianjin, China
State Central Laboratory of Organometallic Compounds, Nankai University, Tianjin, China
3
Moscow State Pedagogical University, ul. M. Pirogovskaya 1, Moscow, 119992 Russia
e-mail: chemdept@mtu-net.ru
Received July 5, 2002
Abstract The reactivity of melezitose hydroxy groups was studied by tritylation in pyridine with subsequent
acetylation. After partial detritylation of the products, acetyl group transfer from position 4 to 6 was observed.
1
The structure of the prepared melezitose derivatives was established on the basis of their IR, H, 13C, and
1H 1H COSY NMR, and mass spectra (fast atom bombardment), as well as from the results of model calcula-
tions performed with the aid of SGI Indigo Molecule-Pattern-Work-Station software package (Biosym) where
the potential energy function was approximated with the CVFF potential. The reactivity of primary hydroxy
groups in melezitose was found to decrease in the following order: 6 > 6
6 > 1 .
Melezitose (I) is a natural trisaccharide, which is
isolated as a white secretion from discharges of leaves
of Alhagi pseudolhagi Desv. legumes and also from
sweet discharges of a number of trees, in particular
teil and poplar. This oligosaccharide exhibits a strong
physiological activity and is widely used in chinese
medicine, e.g., as antibacterial agent [1]. Melezitose
is a nonreducing sugar, -D-glucopyranosyl(1 3)-
-D-fructofuranosyl(2 1)- -D-glucopyranoside. The
goal of the present study was to examine the reactivity
of the melezitose hydroxy groups and the possibility
for selective protection of its primary hydroxy groups.
For this purpose, melezitose was treated with trityl
chloride, and the resulting trityl ethers were subjected
to acetylation with acetic anhydride (Scheme 1).
It is known that triphenylmethyl chloride selec-
tively reacts with primary hydroxy groups of carbo-
hydrates and that acetic anhydride is less selective.
The molecule of melezitose contains 11 hydroxy
groups, four of which are primary. At a TrCl-to-
melezitose molar ratio of 2:1, the major products
were compounds II and III. According to the data
of elemental analysis, molecule II contains two tri-
phenylmethyl groups, and molecule III, only one.
However, it was difficult to determine the position of
trityl moieties in compounds II and III. As reported
in [2, 3, 4], the reactivity of the fructose 1 -OH group
in oligosaccharides containing a saccharose fragment
(e.g., raffinose [5]) is lower than the reactivity of the
other primary hydroxy groups, while the 6 -OH group
is the most reactive. In order to determine the relative
reactivities of primary hydroxy groups in melezitose,
we made an attempt to simulate molecular models of
key compounds II and III. The calculations were per-
formed with the aid of SGI Indigo Molecule-Pattern-
Work-Station software package developed by Biosym.
The potential energy function was approximated with
the CVFF potential [6].
Satisfactory results were obtained by calculation
of compound III. In the tritylation of melezitose,
the reaction at the 1 -OH group is ruled out for the
above reason, and trityl group can be introduced to the
oxygen atom in position 6, 6 , or 6 . The minimal
energies of the corresponding predominant conformers
are 58.06, 41.17, and 61.40 kJ/mol, respectively.
Therefore, the trityl group in molecule III is most
likely to occur just at the 6 -position. This conclusion
1
is supported by the IR, H and 13C NMR, and mass
spectra of compounds II and III.
On the basis of the spectral data, compound II was
assigned the structure of 6,6 -di-O-trityl-1 ,2,2 ,3,-
3 ,4,4 ,4 ,6 -nona-O-acetylmelezitose, and compound
1070-4280/03/3903-0384$25.00 2003 MAIK Nauka/Interperiodica

REACTIVITY OF THE HYDROXY GROUPS IN MELEZITOSE
385
Scheme 1.
II, R1 = R2 = Tr, R3 = R4 = R5 = R6 = Ac; III, R2 = Tr, R1 = R3 = R4 = R5 = R6 = Ac; IV, R1 = Tr, R2 = R3 = R4 = R5 = R6 = Ac;
V, R1 = R2 = R3 = Tr, R4 = R5 = R6 = Ac; VI, R1 = R2 = H, R3 = R4 = R5 = R6 = Ac; VII, R4 = R5 = H, R1 = R2 = R3 = R6 = Ac;
VIII, R5 = H, R1 = R2 = R3 = R4 = R6 = Ac; IX, R2 = H, R1 = R3 = R4 = R5 = R6 = Ac; X, R1 = H, R2 = R3 = R4 = R5 = R6 = Ac;
XI, R2 = Tr, R1 = R3 = R4 = R5 = R6 = H.
III, the structure of 6 -O-trityl-1 ,2,2 ,3,3 ,4,4 ,4 ,6,6 -
deca-O-acetylmelezitose. When the TrCl-to-melezitose
was raised to 4:1, we obtained compound V, 6,6 ,6 -
tri-O-trityl-1 ,2,2 ,3,3 ,4,4 ,4 -octa-O-acetylmelezitose.
This result proves that only three of the four primary
hydroxy groups undergo tritylation. Mote sterically
hindered 1 -OH group fails to react. However, we
observed formation of compound IV which contains
only one trityl group in a different position than in
III, namely at position 6 of the glucose moiety. Thus,
the primary hydroxy groups in melezitose exhibit
different reactivities. The most active is that located
at the 6 -position of the fructose ring while the 1 -OH
group in the same fragment is the least reactive
because of steric hindrances.
It should be noted that heating in acid medium of
the product formed by removal of the trityl protection
from position 6 or 6 of acetylated melezitose leads
to acetyl group migration from position 4 or 4 to
6 or 6 . Such migrations have been well documented
[7]. Insofar as mixture VIII/IX was difficult to
separate, it was heated in acid medium until the
and
5.84 ppm, J1,2 = 3.93 Hz. In the 13C NMR
spectrum, the signal from C2 in the fructofuranose
moiety is displaced downfield due to the presence of
protective groups [8]. We also found that the trityl
group exerts a stronger shielding effect on the neigh-
boring carbon atom than does acetyl group; the corre-
sponding upfield shift ranges from 2 to 3 ppm.
Fast atom bombardment (FAB) mass spectra turned
out to be very useful in the structure determination
of the compounds prepared. The application of FAB
mass spectrometry to structure determination of
oligosaccharides was reported in [9, 10]; in particular,
the mass spectra of melezitose (I) obtained under
bombardment by alkali metal atoms were analyzed
[11, 12]. We were the first to examine the FAB mass
spectra of tritylated and acetylated melezitose deriva-
tives II, III, V VIII, X, and XI which were isolated
by column chromatography. The results are given
in table. The fragmentation pattern is shown in
Scheme 2. Initially, the trisaccharide readily decom-
poses into di- and monosaccharide fragments which
then give rise to smaller species.
It is seen that the relative intensity of the [M+Li]+
ion is as low as 21% if the hydroxy group is located
in position 4 of the fructose moiety and that the
[M+Li]+ ion peak is the most abundant (Irel = 100%)
if the hydroxy group occupies position 6 of the
glucose fragment. It was impossible to determine the
effect of the 6 -OH group on the bond cleavage. The
observed fragment peaks are formed by cleavage of
4
6-Ac migration was complete.
In the H NMR spectra of compounds II and III,
1
signals from the 1 -H proton appear in a stronger
field (as compared with free melezitose) due to effect
of the acetyl groups, so that they fall into the region
corresponding to other protons of carbohydrate rings.
The chemical shifts of 1-H were determined from the
1H H COSY spectra: 5.85 ppm, J1,2 = 3.78 Hz (II),
1
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 39 No. 3 2003

386
TSAO et al.
Scheme 2.
glycoside bonds in the trisaccharide, followed by
successive elimination of acetyl groups.
and the second is formed with participation of the
fructose ring in X (Scheme 3).
Melezitose derivatives having no trityl groups, e.g.,
compounds VIII and X, are characterized by a dif-
ferent fragmentation pattern. The mass spectra of
these compounds contain fragment ion peaks with
m/z 289 and 229, respectively. Presumably, the first
of these originates from the glucose ring of VIII,
Thus our results show that the reactivity of primary
hydroxy groups in melezitose molecule decreases in
the following series: 6 > 6 6 > 1 . On the other
hand, secondary hydroxy groups in the molecule of
the same trisaccharide are characterized by almost
similar reactivities.
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 39 No. 3 2003

REACTIVITY OF THE HYDROXY GROUPS IN MELEZITOSE
387
Scheme 3.
EXPERIMENTAL
10 ps. Every picosecond, one conformer was selected.
Total of 100 conformers were selected, from which
one having the minimal energy was chosen by the
least-squares procedure (RMSD). It was tempered at
lower temperature and optimized again by molecular
All syntheses were carried out in pure anhydrous
solvents. Thin-layer chromatography was performed
on GF-254 plates (China) using the following solvent
systems: A, benzene acetone (7:1); B, diethyl ether
petroleum ether (6:1); C, diethyl ether petroleum
ether (3:1); D, ethyl acetate diethyl ether (2:3); E,
ethyl acetate petroleum ether (2:1); F, ethyl acetate
petroleum ether (1 : 1.5); G, chloroform methanol
(2:1). The melting points were determined on
a Yanaco MP-S3 heating device (Japan). The optical
rotations were measured with a Perkin Elmer-241 MC
polarimeter. Elemental analyses were obtained with
the aid of MT-3 and Perkin Elmer 2400 automatic
analyzers. The IR spectra were recorded on a Perkin
Elmer 325 spectrometer in KBr. The 1H and 13C NMR
spectra were obtained on Bruker AX-400 (400 MHz
Fast atom bombardment mass spectra of melezitose
derivatives II, III, V VIII, X, and XI
Comp.
no.
m/z (Irel, %)
II
1366 [M]+ (7), 1019 [M C6H7O2(OAc)4]+
(7), 242 (100)
III
V
1166 [M]+ (9), 1089 [M C6H5]+ (35), 819
(7), 471 (7), 331 (100)
1589 [M+ Na]+ (0.6), 1573 [M+Li]+ (1.1), 932
[M C6H7O2(OAc)3Tr C2H5OAc]+
(9),
for H and 103.6 MHz for 13C) and Bruker AC-80
1
387 (11), 242 (47.1)
1
instruments (80 MHz for H and 20.1 MHz for 13C)
VI
905 [M+ Na]+ (100), 889 [M+Li]+ (100), 847
[M+ Li CH2CO]+ (28), 863 [M+ Na
CH2CO]+ (25)
using CDCl3 or D2O as solvent and TMS as internal
reference. The mass spectra were run on a VG-ZAB-
HS mass spectrometer (scan range 2000 200 amu,
scan rate 20 s, accelerating voltage 8 kV); bombard-
ment by fast argon atoms; HSCH2CH(OH)CH2OH
NaCl LiCl matrix.
Calculation of molecular models. The calcula-
tions were performed with the use of SGI Indigo
Molecule-Pattern-Work-Station software package
developed by Biosym. The potential energy function
was approximated by the CVFF potential. The initial
conformation was optimized by molecular mechanics
using the fastest descend technique. A sample was
balanced in succession at 300, 500, and 800 K during
VII
905 [M+ Na]+ (100), 889 [M+Li]+ (91), 847
[M+ Li CH2CO]+ (30), 863 [M+ Na
CH2CO]+ (23), 289 (6), 229 (12)
VIII
X
947 [M+ Na]+ (5), 931 [M+Li]+ (21), 331 (7),
289 (9), 229 (18), 169 (60)
947 [M+ Na]+ (20), 931 [M+Li]+ (100), 625
[619+ Li H]+ (7.7), 331 (27), 311 (11), 289
(18), 229 (35)
XI
769 [M+ Na]+ (10), 753 [M+Li]+ (9), 243
[Tr]+ (100), 77 [C6H5]+ (20)
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 39 No. 3 2003

388
TSAO et al.
mechanics. In such a way, the most favorable con-
former was obtained.
128.7, 128.2, 127.9, 127.7, 127.5, 127.1 (Carom);
101.8 (C2 ), 97.5 (C1 ), 92.8 (C1), 88.4 (C3 ), 87.4
(C5 ), 76.6 (C4 ), 75.4 (C2 ), 74.1 (C2), 73.9 (C3 ), 73.5
(C3), 73.4 (C4 ), 72.6 (C4), 72.3 (C5 ), 71.8 (C5), 70.2
(C6 ), 64.1 (C1 ), 63.4 (C6 ), 62.4 (C6), 20.7 (CH3CO).
Found, %: C 64.84; H 5.77. C74H78O25. Calculated,
%: C 64.98; H 5.75.
Isolation of melezitose (I) from the natural blend
Alhagi pseudolhagi Desv. A 200-g portion of the
raw material was kept in hot water (80 90 C) for
30 min, the mixture was filtered, alcohol was added
to the filtrate until it became turbid, and the mixture
was left to stand for 2 3 h. The sticky material was
separated, and 95% ethanol was added to the solution
until a solid precipitated. The precipitate was filtered
off and recrystallized from aqueous ethanol, mp 159
Compound III. Colorless syrup. Yield 3.1 g
(26.8%); Rf 0.28 (A), 0.17 (B); [ ]2D5 +22.6 C (c = 1,
1
CHCl3). IR spectrum, , cm : 1754 (C O), 1493
1
160 C, [ ]2D5 +86.1 (c = 1, H2O).
(Ar). H NMR spectrum (CDCl3), , ppm (J, Hz):
7.43 7.22 m (15H, Harom), 5.84 d.d (1H, 1-H, J1,2
=
6,6 -Di-O-triphenylmethyl-1 ,2,2 ,3,3 ,4,4 ,4 ,6 -
nona-O-acetylmelezitose (II) and 6 -O-triphenyl-
methyl-1 ,2,2 ,3,3 ,4,4 ,4 ,6,6 -deca-O-acetylmele-
zitose (III). Anhydrous melezitose, 5 g (10 mmol),
and triphenylmethyl chloride, 6 g (22 mmol), were
dissolved in 125 ml of dry pyridine, the mixture was
stirred for 18 h at 65 C and cooled to room tempera-
ture, 100 ml of acetic anhydride was added, and the
mixture was stirred for 24 h at room temperature
( 25 C). The mixture was then stirred with ice water
containing 1% of HCl, the precipitate was filtered
off and dissolved in 150 ml of CHCl3, the solution
was washed with water, dried over Na2SO4, and
evaporated under reduced pressure, and the residue
was subjected to column chromatography on silica gel
using diethyl ether petroleum ether (1:1 and 6:1) as
eluent. As a result, compound II was isolated as
a colorless powder, and compound III, as a colorless
syrup.
3.93), 5.79 d.d (1H, 1 -H, J1 ,2 = 3.76), 5.58 m (1H,
4 -H), 5.38 m (1H, 3-H), 5.34 m (1H, 3 -H), 5.19 m
(1H, 4 -H), 5.16 m (1H, 4-H), 4.96 t (1H, 2 -H,
J2 ,3 = 4.56), 4.92 t (1H, 2-H, J2,3 = 3.96), 4.49 d.d
(1H, 3 -H, J3 ,4 = 6.81), 4.37 m (2H, 5-H, 5 -H),
4.29 m (2H, 6-HB, 6 -HB), 4.09 m (1H, 5 -H), 3.99 m
(1H, 6 -HB), 3.95 m (2H, 6-HA, 6 -HA), 3.75 m (1H,
6 -HA), 3.55 d.d (1H, 1 -HB, J1A ,1B = 7.72), 3.34 d.d
(1H, 1 -HA, J1A ,1B = 7.72), 2.13 1.92 (30H,
10CH3CO). 13C NMR spectrum (CDCl3), C, ppm:
170.7, 170.5, 170.3, 169.9, 169.6, 169.4, 169.2
(C O); 143.8, 129.9, 129.3, 128.9, 128.6, 128.4,
127.9, 127.7, 127.6, 127.3 (Carom); 101.7 (C2 ), 97.6
(C1 ), 92.9 (C1), 88.4 (C3 ), 87.5 (C5 ), 76.7 (C4 ), 75.6
(C2 ), 74.2 (C2), 73.9 (C3 ), 73.7 (C3), 73.5 (C4 ), 72.8
(C4), 72.6 (C5 ), 71.9 (C5), 70.1 (C6 ), 64.1 (C1 ), 62.9
(C6 ), 61.3 (C6), 20.6 (CH3CO). Found, %: C 58.38;
H 5.69. C57H66O26. Calculated, %: C 58.64; H 5.70.
Compound II. Colorless crystals from CHCl3
MeOH. Yield 1.3 g (9.6%); mp 178 180 C; Rf 0.54
6-O-Triphenylmethyl-1 ,2,2 ,3,3 ,4,4 ,4 ,6 ,6 -
deca-O-acetylmelezitose (IV) and 6,6 ,6 -tri-O-tri-
phenylmethyl-1 ,2,2 ,3,3 ,4,4 ,4 -octa-O-acetyl-
melezitose (V). Following an analogous procedure,
compounds IV and V were obtained from 5 g
(10 mmol) of anhydrous melezitose and 13 g
(44 mmol) of triphenylmethyl chloride.
(A), 0.39 (B), 0.25 (C); [ ]2D5 +118 (c = 0.1, CHCl3).
1
IR spectrum, , cm : 1751 (C O); 1648, 1490 (Ar).
1H NMR spectrum (CDCl3), , ppm (J, Hz): 7.42
7.22 m (30H, Harom), 5.85 d.d (1H, 1-H, J1,2 = 3.78),
5.77 d.d (1H, 1 -H, J1 ,2 = 4.09), 5.45 m (1H, 3 -H),
5.39 m (1H, 4 -H), 5.36 d.d (1H, 3-H, J3,4 = 9.46),
5.20 d.d (1H, 4-H, J4,5 = 8.29), 4.96 d.d (1H, 4 -H,
Compound IV. Colorless syrup. Yield 1.9 g
1
(16.4%); Rf 0.27 (A), 0.16 (B). IR spectrum, , cm :
1
J4 ,5
4.85 d.d (1H, 2-H, J2,3 = 7.98), 4.49 d.d (1H, 3 -H,
J3 ,4 = 5.91), 4.33 d.d (1H, 5-H, J5,6A = 2.0, J5,6B
=
4.49), 4.92 d.d (1H, 2 -H, J2 ,3 = 4.25),
1753 (C O), 1498 (Ar). H NMR spectrum (CDCl3),
, ppm (J, Hz): 7.40 7.25 m (15H, Harom), 5.80 d.d
=
(1H, 1-H, J1,2 = 3.89), 5.78 d.d (1H, 1 -H, J1 ,2
=
4.60), 4.30 m (1H, 6 -HB), 4.28 m (1H, 5 -H),
4.16 d.d (1H, 6-HB, J6A,6B = 8.03), 4.02 m (1H,
6 -HA), 4.00 m (1H, 5 -H), 3.95 d.d (1H, 6-HA,
J6A,6B = 8.03), 3.83 m (1H, 6 -HB), 3.73 m (1H,
6 -HA), 3.30 d.d (1H, 1 -HB, J1A ,1B = 8.04), 3.13 d.d
(1H, 1 -HA, J1A ,1B = 8.04), 2.15 1.90 (27H,
9CH3CO). 13C NMR spectrum (CDCl3), C, ppm:
170.9, 170.6, 170.4, 170.3, 170.1, 169.7, 169.5,
169.3, 169.1 (C O); 143.6, 129.8, 129.1, 128.9,
3.76), 5.56 d.d (1H, 4 -H, J4 ,5 = 7.21), 5.35 d.d (1H,
3-H, J3,4 = 9.18), 5.31 m (1H, 3 -H), 5.15 d.d (1H,
4 -H, J3 ,4 = 3.57), 5.12 d.d (1H, 4-H, J3,4 = J4,5
=
9.18), 4.95 d.d (1H, 2 -H, J2 ,3 = 3.24), 4.91 d.d (1H,
2-H, J2,3 = 3.78), 4.49 d.d (1H, 3 -H, J3 ,4 = 6.78),
4.38 m (1H, 5 -H), 4.29 m (1H, 5 -H), 4.27 m (1H,
6 -HB), 4.24 m (1H, 5-H), 4.17 m (1H, 6 -HB), 4.00 m
(1H, 6 -HA), 3.97 m (1H, 6 -HA), 3.77 m (1H, 6-HB),
3.65 m (1H, 6-HA), 3.57 d.d (1H, 1 -HB, J1A ,1B
=
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 39 No. 3 2003

REACTIVITY OF THE HYDROXY GROUPS IN MELEZITOSE
389
8.04), 3.33 d.d (1H, 1 -HA, J1A ,1B = 8.04), 2.15 1.97
(30H, 10CH3CO). 13C NMR spectrum (CDCl3),
J4 ,5 = 10.35), 5.37 m (1H, 3-H), 5.29 d.d (1H, 4-H,
J4,5 = 8.36), 4.98 d.d (1H, 4 -H, J4 ,5 = 5.34),
4.75 d.d (1H, 2 -H, J2 ,3 = 5.68), 4.45 d.d (1H, 2-H,
J2,3 = 4.10), 4.49 d.d (1H, 3 -H, J3 ,4 = 8.21), 4.34 m
(1H, 5-H), 4.31 m (1H, 6 -HB), 4.29 m (1H, 5 -H),
,
C
ppm: 170.6, 170.4, 170.2, 169.8, 169.6, 169.3, 169.1
(C O); 143.8, 129.9, 129.3, 128.9, 128.7, 128.5,
127.9, 127.8, 127.5, 127.2 (Carom); 102.3 (C2 ), 98.1
(C1 ), 92.9 (C1), 88.1 (C3 ), 87.3 (C5 ), 76.6 (C4 ), 75.4
(C2 ), 74.1 (C2), 73.8 (C3 ), 73.6 (C3), 73.3 (C4 ), 72.6
(C4), 72.4 (C5 ), 71.8 (C5), 70.1 (C6 ), 64.3 (C1 ), 62.8
(C6 ), 62.5 (C6), 20.8 (CH3CO). Found, %: C 58.47;
H 5.57. C57H66O26. Calculated, %: C 58.64; H 5.70.
4.09 m (1H, 6 -HA), 4.06 d.d (1H, 6-HB, J6A,6B
=
10.0), 3.91 m (1H, 5 -H), 3.82 m (1H, 6 -HB), 3.78 d.d
(1H, 6-HA, J6A,6B = 10.0), 3.71 m (1H, 6 -HA), 3.65 d.d
(1H, 1 -HB, J1A ,1B = 6.01), 3.61 d.d (1H, 1 -HA,
J1A ,1B = 6.01), 2.15 1.90 (27H, 9CH3CO). Found, %:
C 49.46; H 5.70. C36H50O25. Calculated, %: C 48.96;
H 5.71.
Compound V. Colorless syrup. Yield 5.3 g
(34.2%); Rf 0.65 (A); [ ]2D5 +91.3 C (c = 0.1, CHCl3).
1 ,2,2 ,3,3 ,4 ,6,6 ,6 -Nona-O-acetylmelezitose
(VII). Compound VI, 0.5 g (0.6 mmol), was dissolved
in 10 ml of benzene, and 3 ml of glacial acetic acid
was added to the solution. The mixture was heated to
the boiling point on an oil bath and was stirred for
16 h. The progress of the reaction was monitored by
TLC using solvent system D. When the reaction was
complete, the mixture was evaporated under reduced
pressure, and the residue was subjected to preparative
thin-layer chromatography on silica gel using solvent
system D. Product VII was isolated as a colorless
syrupy substance. Yield 0.38 g (76%); Rf 0.41 (D),
0.19 (E); [ ]2D5 +71 (c = 0.1, CHCl3). IR spectrum,
1
IR spectrum, , cm : 1745 (C O); 1600, 1490 (Ar).
1H NMR spectrum (CDCl3), , ppm (J, Hz): 7.43
7.20 m (45H, Harom), 5.66 d.d (1H, 1-H, J1,2 = 3.67),
5.65 d.d (1H, 1 -H, J1 ,2 = 3.62), 5.41 d.d (1H, 3 -H,
J3 ,4 = 5.94), 5.38 m (2H, 3-H, 3 -H), 4.99 m (2H,
4-H, 4 -H), 4.86 m (2H, 2-H, 2 -H), 4.51 d.d (1H,
4 -H, J4 ,5 = 6.34), 4.29 m (2H, 5-H, 5 -H), 4.01 m
(1H, 6 -HB), 3.86 m (4H, 6-H, 6 -H), 3.82 m (1H,
5 -H), 3.74 m (1H, 6 -HA), 3.32 d.d (1H, 1 -HB,
J1A ,1B = 8.04), 3.15 d.d (1H, 1 -HA, J1A ,1B = 8.04),
2.15 1.90 (24H, 8 CH3CO). 13C NMR spectrum
(CDCl3), C, ppm: 171.1, 170.9, 170.6, 170.3, 170.2,
169.8, 169.6, 169.2, 168.9 (C O); 143.7, 129.9,
129.2, 128.9, 128.8, 128.3, 127.9, 127.7, 127.3, 126.7
(Carom); 101.9 (C2 ), 95.6 (C1 ), 92.8 (C1), 89.0 (C3 ),
87.1 (C5 ), 76.4 (C4 ), 75.3 (C2 ), 74.1 (C2), 73.8 (C3 ),
73.5 (C3), 73.3 (C4 ), 72.4 (C4), 72.1 (C5 ), 71.5 (C5),
70.1 (C1 ), 63.4 (C6 ), 63.0 (C6 ), 62.2 (C6), 20.7
(CH3CO). Found, %: C 70.50; H 6.02. C91H90O24.
Calculated, %: C 69.72; H 5.79.
1
1
, cm : 3422 (4,4 -OH), 1750.6 (C O). H NMR
spectrum (CDCl3), , ppm (J, Hz): 5.74 d.d (1H, 1-H,
J1,2 = 4.58), 5.61 d.d (1H, 1 -H, J1 ,2 = 3.32), 5.47 m
(1H, 3 -H), 5.36 m (1H, 3-H), 4.96 d.d (1H, 4 -H,
J4 ,5 = 4.49), 4.92 d.d (1H, 2 -H, J2 ,3 = 5.25),
4.85 d.d (1H, 2-H, J2,3 = 3.78), 4.52 d.d (1H, 3 -H,
J3 ,4 = 5.91), 4.40 m (1H, 4 -H), 4.32 m (1H, 5-H),
4.30 m (1H, 6 -HB), 4.28 m (1H, 5 -H), 4.21 m (1H,
6-HB), 4.05 m (1H, 6 -HB), 4.02 m (1H, 6 -HA),
4.00 m (1H, 6-HA), 3.96 m (1H, 6 -HA), 3.83 m (1H,
1 ,2,2 ,3,3 ,4,4 ,4 ,6 -Nona-O-acetylmelezitose
(VI). Compound II, 4.5 g (3.3 mmol), was dissolved
in 40 ml of methylene chloride, 40 ml of glacial acetic
acid and 0.8 ml of concentrated hydrochloric acid
were added to the solution, and the mixture was
stirred for 1.5 h on cooling with ice water. The prog-
ress of the reaction was monitored by TLC (solvent
system D). The mixture was neutralized with a sa-
turated solution of NaHCO3, washed with water, dried
over Na2SO4, and evaporated under reduced pressure.
The residue was subjected to column chromatography
on silica gel using ethyl acetate petroleum ether
(1:1 and 2:1) to isolate compound VI as a colorless
syrupy substance. Yield 1.9 g (73%); Rf 0.29 (D),
0.11 (E); [ ]2D5 +101 (c = 0.1, CHCl3). IR spectrum,
5 -H), 3.58 m (1H, 4-H), 3.33 d.d (1H, 1 -HB, J1A ,1B
6.50), 3.18 d.d (1H, 1 -HA, J1A ,1B = 6.50), 2.32 2.02
(27H, 9CH3CO). 13C NMR spectrum (CDCl3),
=
,
C
ppm: 170.9, 170.6, 170.4, 170.2, 170.1, 169.6, 169.3,
169.1, 168.9 (C O); 102.3 (C2 ), 97.3 (C1 ), 92.8
(C1), 89.9 (C3 ), 82.3 (C5 ), 76.2 (C4 ), 75.3 (C2 ), 74.1
(C2), 73.6 (C3 ), 73.4 (C3), 73.2 (C4 ), 72.4 (C4), 72.2
(C5 ), 71.7 (C5), 70.0 (C6 ), 63.9 (C1 ), 62.3 (C6 ), 61.2
(C6), 20.6 (CH3CO). Found, %: C 49.80; H 5.70.
C36H50O25. Calculated, %: C 48.96; H 5.71.
1 ,2,2 ,3,3 ,4,4 ,6,6 ,6 -Deca-O-acetylmelezitose
(VIII). Following the procedure described above for
the synthesis of compound VI, from 5 g (4.3 mmol)
of compound III we obtained 2.8 g of a mixture of
products VIII and IX [IX: Rf 0.49 (D), 0.17 (F)].
A 0.5-g portion of mixture VIII/IX was dissolved
1
, cm : 3524 (6,6 -OH), 1743 (C O). 1H NMR
spectrum (CDCl3), , ppm (J, Hz): 5.76 d.d (1H, 1-H,
J1,2 = 5.68), 5.67 d.d (1H, 1 -H, J1 ,2 = 3.34),
5.57 d.d (1H, 3 -H, J3 ,4 = 12.7), 5.39 d.d (1H, 4 -H,
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 39 No. 3 2003

390
TSAO et al.
in 10 ml of benzene, 3 ml of glacial acetic acid was
added, and the mixture was heated to the boiling point
and was stirred for 36 h under reflux (TLC). The mix-
ture was evaporated under reduced pressure, and the
residue was separated by thin-layer chromatography
on silica gel using solvent system D. Product VIII
was isolated as a colorless syrupy substance. Yield
0.34 g (68%); Rf 0.57 (D), 0.25 (F); [ ]2D5 +106
6 -O-Triphenylmethylmelezitose (XI). Metallic
sodium was added to 15 ml of anhydrous methanol
to attain pH 9, and 0.5 g of compound III was added.
The mixture was stirred for 2 h at room temperature,
neutralized with glacial acetic acid, and evaporated
under reduced pressure, and the residue was subjected
to column chromatography on silica gel using chloro-
form methanol (4 : 1) as eluent. Product XI was
isolated as a colorless syrupy substance. Yield 0.26 g
(82%); Rf 0.25 (G), 0.36 (F); [ ]2D5 +65 (c = 0.1,
1
(c = 0.1, CHCl3). IR spectrum, , cm : 3528 (OH),
1
1751 (C O). H NMR spectrum (CDCl3), , ppm
1
(J, Hz): 5.71 d.d (1H, 1-H, J1,2 = 3.55), 5.63 d.d (1H,
1 -H, J1 ,2 = 3.80), 5.57 m (1H, 3 -H), 5.39 d.d (1H,
3-H, J3,4 = 7.48), 5.28 m (1H, 4-H), 5.26 m (1H,
4 -H), 4.98 m (1H, 2 -H), 4.94 m (1H, 2-H), 4.74 d.d
(1H, 3 -H, J3 ,4 = 3.87), 4.43 m (1H, 5-H), 4.41 m
(1H, 6 -HB), 4.40 m (1H, 4 -H), 4.37 m (1H, 5 -H),
4.34 m (1H, 6 -HA), 4.28 m (1H, 6-HB), 4.05 m (1H,
5 -H), 4.11 d.d (1H, 6 -HB, J6A ,6B = 11.87), 4.04 m
(1H, 6-HA), 3.92 d.d (1H, 6 -HA, J6A ,6B = 11.87),
3.57 m (1H, 1 -HB), 3.43 m (1 -HA), 2.13 1.92 (30H,
10CH3CO). 13C NMR spectrum (CDCl3), C, ppm:
171.9, 171.5, 170.7, 170.2, 170.1, 169.9, 169.7
(C O); 102.4 (C2 ), 97.8 (C1 ), 93.0 (C1), 88.5 (C3 ),
87.7 (C5 ), 75.7 (C2 ), 74.6 (C2), 74.3 (C4 ), 73.9 (C3 ),
73.7 (C3), 73.5 (C4 ), 72.8 (C4), 72.6 (C5 ), 71.9 (C5),
70.5 (C6 ), 64.2 (C1 ), 63.0 (C6 ), 61.5 (C6), 20.6
(CH3CO). Found, %: C 49.13; H 5.62. C38H52O26.
Calculated, %: C 49.34; H 5.67.
H2O). IR spectrum, , cm : 3425 (OH); 1633, 1491
(Ar). 1H NMR spectrum (D2O), , ppm (J, Hz):
5.45 d.d (1H, 1-H, J1,2 = 3.80), 5.18 d.d (1H, 1 -H,
J1 ,2 = 3.80), 4.32 d.d (1H, 3 -H, J3 ,4 = 7.60),
4.30 d.d (1H, 4 -H, J3 ,4 = 7.60, J4 ,5 = 8.0), 3.94 d.d
(1H, 5-H, J5,6A = 2.20, J5,6B = 4.80), 3.93 d.d (1H,
5 -H, J5 ,6A = 2.20, J5 ,6B = 4.80), 3.91 d.d (1H, 5 -H,
J4 ,5 = 8.0), 3.90 d.d, (1H, 6-HB, J5,6B = 4.80),
3.86 d.d (1H, 6 -HB, J5 ,6B = 4.80), 3.81 d.d (1H,
1 -HB, J1A ,1B = 12.0), 3.79 d.d (1H, 6 -HA, J6A ,6B
=
12.2), 3.78 d.d (1H, 6-HA, J6A,6B = 12.2), 3.75 d.d
(1H, 3 -H, J2 ,3 = 10.0, J3 ,4 = 9.0), 3.67 d.d (1H,
3-H, J2,3 = 10.0, J3,4 = 8.80), 3.65 d.d (1H, 1 -HA,
J1A ,1B = 12.0), 3.58 d.d (1H, 2 -H, J1 ,2 = 3.80,
J2 ,3 = 10.0), 3.56 d.d (1H, 2-H, J1,2 = 3.80, J2,3
=
10.0), 3.53 m (2H, 6 -HA, 6 -HB), 3.45 d.d (1H, 4 -H,
J3 ,4 = 9.0, J4 ,5 = 10.2), 3.44 d.d (1H, 4-H, J3,4
8.80, J4,5 = 10.2). 13C NMR spectrum (D2O),
=
,
C
1 ,4 ,2,2 ,3,3 ,4,4 ,6 ,6 -Deca-O-acetylmelezitose
(X) was synthesized in a similar way from compound
IV. Colorless syrupy substance. Yield 1.8 g (69%);
ppm: 104.8 (C2 ), 101.0 (C1 ), 92.7 (C1), 84.3 (C3 ),
78.4 (C5 ), 74.6 (C4 ), 74.1 (C2 ), 73.8 (C2), 73.2 (C3 ),
72.5 (C3), 71.9 (C4 ), 70.6 (C4), 70.3 (C5 ), 70.0 (C5),
63.2 (C6 ), 62.4 (C1 ), 61.4 (C6), 60.4 (C6 ). Found, %:
C 59.48; H 6.22. C37H46O16. Calculated, %: C 59.51;
H 6.21.
Rf 0.41 (D); [ ]2D5 +134 (c = 0.1, CHCl3). IR spec-
1
1
trum, , cm : 3450 (OH), 1735 (C O). H NMR
spectrum (CDCl3), , ppm (J, Hz): 5.81 d.d (1H, 1-H,
J1,2 = 3.89), 5.79 d.d (1H, 1 -H, J1 ,2 = 3.78), 5.56 d.d
(1H, 4 -H, J4 ,5 = 7.17), 5.33 m (1H, 3-H), 5.30 m
(1H, 3 -H), 5.16 d.d (1H, 4 -H, J4 ,5 = 3.57), 5.11 d.d
The authors are thankful to the State Foundation
for Natural Sciences of China for financial support
(no. 29962002).
(1H, 4-H, J4,5 = 9.18), 4.94 d.d (1H, 2 -H, J2 ,3
=
3.24), 4.90 d.d (1H, 2-H, J2,3 = 3.78), 4.49 d.d (1H,
3 -H, J3 ,4 = 6.12), 4.39 m (1H, 5 -H), 4.28 m (1H,
5 -H), 4.26 m (1H, 6 -HB), 4.24 m (1H, 5-H), 4.18 m
(1H, 6 -HB), 4.08 m (1H, 6-HB), 3.99 m (1H, 6 -HA),
3.97 m (1H, 6 -HA), 3.76 m (1H, 6-HA), 3.60 d.d (1H,
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