Selective reduction of anomeric azides to amines with tetrathiomolybdate: Synthesis of β-D-glycosylamines

Article abstract of DOI:10.1021/jo0266947

A number of β-glycosyl azide derivatives undergo reduction on treatment with tetrathiomolybdate to produce the corresponding β-D-glycosylamines exclusively without anomerization under very mild and neutral reaction conditions. Acetyl, allyl, benzoyl, and

Full text of DOI:10.1021/jo0266947

Selective Red u ction of An om er ic Azid es to Am in es w ith
Tetr a th iom olybd a te: Syn th esis of â-D-Glycosyla m in es
Perali Ramu Sridhar, Kandikere Ramaiah Prabhu, and Srinivasan Chandrasekaran*,†
Department of Organic Chemistry, Indian Institute of Science, Bangalore 560 012, Karnataka, India
scn@orgchem.iisc.ernet.in
Received November 12, 2002
A number of â-D-glycosyl azide derivatives undergo reduction on treatment with tetrathiomolybdate
to produce the corresponding â-D-glycosylamines exclusively without anomerization under very
mild and neutral reaction conditions. Acetyl, allyl, benzoyl, and benzyl protective groups are left
untouched under the reaction conditions. An exclusive selectivity in the reduction of anomeric azides
is observed, while the C-2 and C-6 azides are left untouched.
The glycopeptides are central to the chemistry and
biology of glycoproteins, which have gained considerable
prominence in recent years due to their biological and
ization of the reduced product is the major limitaion.7
Although a number of methods have been developed for
stereoselective and chemoselective reduction of anomeric
1
8
pharmacological significance. In particular, the inves-
azides, an efficient strategy for producing anomeric am-
tigations directed toward understanding the role of
oligosaccharides in glycopeptides continue to attract con-
siderable attention because of their significant role in
affecting the structure and function of O-glycoproteins
ines with stereochemical integrity is still a challenging
problem. Herein we report a facile synthetic strategy
for the selective reduction of anomeric azides to â-pyra-
nosylamines utilizing benzyltriethylammonium tetrathi-
omolybdate 19 under mild and neutral reaction condi-
tions. In addition, a regioselective reaction to produce
1d
2
and N-glycoproteins. In this context, a user-friendly pro-
cedure is highly desirable in order to synthesize glyco-
sylamines with the desired stereochemistry, which has
far reaching relevance in the synthesis of N-glycopep-
tides. Of the various procedures available for the syn-
thesis of the amines, the reduction of azides is the most
2
-azido-â-pyranosylamine in high yields is also described.
In our research program to explore the utility of
3 2
benzyltriethylammonium tetrathiomolybdate ([BnNEt ] -
1
0
3
MoS ), 1, in organic synthesis, we have reported earlier
attractive because of their easy accessibility. The most
4
the synthesis of disulfides11 and diselenides. While aryl
12
prominent reagents employed for such conversions are
LAH4 and metal-catalyzed hydrogenations, which are
generally nonselective. However, there are serious im-
pediments associated with the reduction of sugar azides
to the corresponding amines. For example, the reduction
should be carried out without affecting the protective
5
azides on treatment with 1 led to the formation of
arylamines, alkyl azides gave imines as a product of the
reaction (Scheme 1).13
The sugar azides 2,14 4,15 6,16 8,17 10,18 12,19 14,19 16,20
21
20
22
14
1
7, 18, 20, and 22 were synthesized using standard
6
groups and in the case of anomeric azides, the anomer-
protocols. The diazide 20 was synthesized from the
corresponding triacetyl galactal. The azide 17 was syn-
thesized from the corresponding glucosamine utilizing
diazotransfer methodology.
*
Author for correspondence: Phone: +91-80-394 2404. Fax: +91-
8
0-360 0529.
†
Honorary Professor, J awaharlal Nehru Center for Advanced
Scientific Research, Bangalore. Dedicated to Professor Goverdhan
Mehta on the occasion of his 60th birthday.
(
1) (a) Davis, B. G. Chem. Rev. 2002, 102, 579. (b) Scriven, E. F. V.;
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Am. Chem. Soc. 1993, 115, 10531.
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5
87. (d) Kunz, H. Angew. Chem., Int. Ed. Engl. 1987, 26, 294.
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(
1
62.
(
3) (a) Ranu, B. C.; Sarkar, A.; Chakraborty, R. J . Org. Chem. 1994,
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3277
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Org. Chem. 1978, 43, 1972.
5
1
9, 4114 and references therein. (b) Hays, D. S.; Fu, G. C. J . Org. Chem.
998, 63, 2796. (c) Peters, R. G. Warner, B. P.; Burns, C. J . J . Am.
Chem. Soc. 1999, 121, 5585.
4) (a) Boyer, J . H. J . Am. Chem. Soc. 1951, 73, 5865. (b) Boyer, J .
(
H.; Canter, F. C. Chem. Rev. 1954, 54, 1. (b) Kyba, E. P.; J ohn, A. M.
Tetrahedron Lett. 1977, 18, 2737.
(
5) (a) Kunz, H.; Unverzagt, C. Angew. Chem., Int. Ed. Engl. 1988,
7, 1697. (b) Corey, E. J .; Nicolaou, K. C.; Balanson, R. D.; Machida,
Y. Synthesis 1975, 590.
6) Haddad, J .; Kotra, L. P.; Llano-Sotelo, B.; Kim, C.; Azucena, E.
2
(
F.; Liu, M. J r.; Vakulenko, S. B.; Chow, C. S.; Mobashery, S. J . Am.
Chem. Soc. 2002, 124, 3229 and references therein.
1
0.1021/jo0266947 CCC: $25.00 © 2003 American Chemical Society
Published on Web 05/29/2003
J . Org. Chem. 2003, 68, 5261-5264
5261

Sridhar et al.
SCHEME 1
TABLE 1. Red u ction of An om er ic Azid es w ith
Tetr a th iom olybd a te 1
In the initial experiments, treatment of glycopyronasyl
azide 2 with tetrathiomolybdate 1 (1 equiv) at room
temperature (CH CN/EtOH (1:1), 28 °C, stirring, 8 h)
3
produced an excellent yield of the reduced product, tetra-
O-acetyl-â-glycosylamine, 323 (96%). Interestingly, the
reaction of the anomeric azide 2 with 1 is analogous to
the reaction of aryl azides rather than the alkyl azides.
It is important to recognize that the reduction is com-
pletely selective and only the â-anomer is formed exclu-
sively in near quantitative yield. Further, the reaction
of benzyl-, benzoyl-, and allyl-protected â-glycosyl azides
4
5
, 6, and 8 produced the corresponding â-glycosylamines
1
5
16
,
7, and 9 in very good yields, indicating the versatil-
ity of the reaction (entries 3-5; Table 1). Unlike the LAH
reduction or metal-catalyzed reductions, the other protec-
tive groups were not affected under the reaction condi-
tions. Treatment of the N-acetylglucosaminyl-â-azide 10
with tetrathiomolybdate 1 gave the corresponding 2-ac-
etamido-3,4,6-tri-O-acetyl-glucopyranosylamine 1118 in
excellent yield. This amine 11 is an important starting
material for the synthesis of N-linked glycopeptides.8
The methodology was also applied in the case of disac-
charide-derived azide 12, which on treatment with 1 gave
the corresponding anomeric amine 13 in very good yield.
To check the effect of the neighboring group at C-2 in
these reactions, the 2-deoxy derivative 14 was subjected
to reaction with 1, and in this case also the amine 15
was isolated as the only product.
b,24
a
Reactions carried out under stirring. b Under sonication. All
c
d
compounds exhibited expected spectral and analytical data. Iso-
lated yields.
TABLE 2. Selective Red u ction of An om er ic Azid es w ith
Tetr a th iom olybd a te 1
After optimizing the conditions for the reduction of
anomeric azides, the methodology was applied for the
reduction of C-2 and C-6 azides. Surprisingly, reaction
of C-6 and C-2 azides (1620 and 17, respectively; entries
21
1
and 2, Table 2) with tetrathiomolybdate 1 did not
produce any reduction products even after an extended
reaction time (72 h). The unreactivity of C-2 and C-6
azides toward tetrathiomolybdate 1 presents a unique
opportunity to explore the reactivity of anomeric azides
in the presence of other sugar azides with tetrathiomo-
lybdate 1. Thus diazides 18 and 20 on treatment with
(
16) Chida, N.; Suzuki, T.; Tanaka, S.; Yamada, I. Tetrahedron Lett.
999, 40, 2573 and references therein.
17) Toth, I.; McGeary, R. P.; West. M. L.; Ramsdale, T. E. AU Patent
002032963, 2002; Chem. Abstr. 2002, 136, 341002.
18) Cunha, A. C.; Pereira, L. O. R.; de Souza, R. O. P.; de Souza, M
C. B. V.; Ferreira, V. F. Nucleosides Nucleotides Nucleic Acids 2001,
1
(
2
(
a
Reactions carried out under stirring. b Under sonication. All
c
d
compounds exhibited expected spectral and analytical data. Iso-
lated yields.
2
0, 1555.
(19) Walter, A. S.; Osman, A., J r.; J an, P.; Bruno, K. R. Tetrahedron
1
978, 38, 1427.
(20) Lowary, T. L.; Hindsgaul, O. Carbohydr. Res. 1994, 251, 33.
21) Vasella, A.; Witzig, C.; Chiara, J .-L.; Martin-Lomas, M. Helv.
(
Chim. Acta 1991, 74, 2073.
tetrathiomolybdate 1 (excess) produced 6-azido-â-glyco-
sylamine 19 and 2-azido-â-glycosylamine 21, respectively,
as the only products in excellent yield (entries 3 and 4,
Table 2). It is interesting to note that the C-6 and C-2
azides are inert under the reaction conditions, whereas
the anomeric azides are selectively reduced to the cor-
(
22) Snider, B. B.; Lin, H. Synth. Commun. 1998, 28, 1913.
(23) Takeda, T.; Sugiura, Y.; Ogihara, Y.; Shibata, S. Can. J . Chem.
1
980, 58, 2600.
24) (a) Haneda, K.; Inasu, T.; Yamamoto, K.; Nakahara, Y.; Kobata,
(
A. Carbohydr. Res. 1996, 292, 61. (b) Wang, X. L.; Tang, M.; Suzuki,
T.; Kitajima, K.; Inoue, Y.; Inoue, S.; Fan, J . Q.; Lee, Y. C. J . Am. Chem.
Soc. 1997, 119, 11137.
5
262 J . Org. Chem., Vol. 68, No. 13, 2003

Synthesis of â-D-Glycosylamines
SCHEME 2. Su lfu r Tr a n sfer a n d Red u ction of
Azid es Assisted by Tetr a th iom olybd a te 1
SCHEME 3
responding â-glycosylamines, 19 and 21, in very good
yields. To the best of our knowledge, this type of regio-
selective reduction of anomeric azides is very rare.
Additionally, this methodology presents an opportunity
to synthesize an interesting diaminodisulfide analogue
2
3 in one pot. Accordingly, treatment of 6-tosyl-2,3,4-tri-
1
4
O-acetyl-â-D-glucopyranosyl azide 22 with tetrathiomo-
lybdate 1 (2 equiv) produced the corresponding â-glyco-
sylamine disulfide 23 as the only product in excellent
yield (Scheme 2). Interestingly, this transformation
involves two processes mediated by tetrathiomolybdate
1
: sulfur transfer to form the disulfide and at the same
time the reduction of the anomeric azide. It turned out
that when the reaction of 2 with 1 was carried out under
sonochemical conditions (CH CN/EtOH, ultrasonic clean-
3
ing bath, 25 kHz, 28 °C), it was completed in 2 h giving
rise to the â-glycosylamine 3 in 96% yield. Therefore, all
the subsequent experiments on reduction of azido sugars
were also carried out under sonochemical conditions.
A plausible mechanism based on the reactivity of
tetrathiomolybdate is presented in Scheme 3. There are
two possible modes of attack of the sulfur nucleophile of
2
-
1
on organic azide. In pathway A, MoS
4
attacks the
R-nitrogen of the azide to give a N-sulfenylamine 24
following nitrogen extrusion, which subsequently gives
rise to the amine and the mononuclear persulfido mo-
lybdenum(IV) species 25. The intermediate 25 gets
Exp er im en ta l Section
2
-
converted to the Mo(V) dimmer, Mo
possible to visualize a pathway B where the MoS
attacks the γ-nitrogen of the azide resulting in interme-
diate 27, which decomposes to give the amine, N , and
2
S
8
, 26. It is also
Gen er a l Meth od s. All reactions were performed in an
oven-dried apparatus. Reaction mixtures were stirred mag-
netically unless otherwise stated. The products were charac-
terized by NMR, FTIR, and GCMS. Commercial-grade solvents
were distilled prior to use. Chloroform, dichloromethane, and
acetonitrile were initially dried over phosphorus pentoxide and
stored over 4 Å molecular sieves. H and C NMR spectra were
recorded at 300 and 75 MHz, respectively. Coupling constants
are reported in hertz. Infrared (IR) spectra were measured as
2
-
4
, 1
2
mononuclear molybdenum species 25. Irrespective of
which pathway is followed, the expected byproduct is
Mo(V) dimer, 26. This Mo(V) dimer, 26, has been
synthesized by other routes.25 In the reaction of anomeric
azides with 1, the molybdenum byproduct has been
isolated and characterized as 26.26 The observed selectiv-
ity of 1 at the anomeric azide may be due to increased
electrophilicity at this center.
1
13
CHCl
3
solution or as thin film.
Da ta for 2,3,4,6-Tetr a -O-a llyl-â-D-glu cop yr a n osyl Azid e
1
7
-1
1
(
8). IR (neat): 3080, 3016, 2114, 1646 cm . H NMR (300
MHz, CDCl
3
): δ 5.99-5.85 (m, 4H), 3.32-5.14 (m, 8H), 4.50
(
d, 1H, J ) 9 Hz), 4.22-4.31 (m, 4H), 4.15-4.02 (m, 4H), 3.67
In summary, we have developed a mild and neutral
method to synthesize â-glycosylamines in excellent yield
under mild and neutral conditions using tetrathiomoly-
bdate 1 as the key reagent. The striking feature of this
methodology is that it tolerates a number of other
functional groups. More importantly, the stereoselective
reaction produces exclusively the â-anomer, presents a
rare regioselectivity in the reduction of anomeric azides
in the presence of C-2 and C-6 azides, and may find useful
applications in carbohydrate chemistry.
13
(q, 2H, J ) 11 Hz), 3.40 (bs, 3H), 3.13 (t, 1H, J ) 7.5 Hz).
C
NMR (75 MHz, CDCl ): δ 134.9. 134.5, 134.4, 134.4, 117.4,
3
117.1, 116.9, 116.7, 89.9, 84.2, 80.8, 76.9, 76.8, 74.3, 73.8, 73.7,
+
7
2.5, 68.3. EIMS m/ z: 337 (M - 28).
Da ta for 2-Aceta m id o-2-d eoxy-3,4,6-tr i-O-a cetyl-â-D-
glu cop yr a n osyl Azid e (10). IR (neat): 3332 (NH), 2104
1
8
-
1
1
(
N
3
), 1748 and 1660 (CO) cm . H NMR (300 MHz, CDCl
δ 5.27 (dd, 1H, J ) 9.9 Hz), 5.10 (dd, 1H, J ) 9.6 Hz), 4.81 (d,
H, J ) 9.3 Hz), 4.28 (dd, 1H, J ) 4.5 Hz, J ) 12.3 Hz), 4.16
dd, 1H, J ) 2.1 Hz, J ) 12.3 Hz), 3.93 (m, 1H), 3.78-3. 84
(m,1H), 2.11 (s, 3H), 2.04 (s, 3H), 2. 03 (s,3H), 1.98 (s, 3H).
3
):
1
(
1
3
3
C NMR (75 MHz, CDCl ): 170.8, 170.6, 170.5, 169.2, 88.3,
7
3
3.8, 72.1, 68.0, 61.8, 53.9, 23.1, 20.6, 20.5, 20.5. EIMS m/z:
(
25) Pan, W. H.; Harmer, M. A.; Halbert, T. R.; Stiefel, E. I. J . Am.
Chem. Soc. 1984, 106, 459.
26) IR spectrum (KBr) of the molybdenum byproduct shows a strong
+
73 (MH ).
H ep t a -O-a cet yl-â-D-la ct op yr a n osyl Azid e (12).19 IR
(
-1
-1 1
absorption at 520 cm assignable to a persulfido molybdenum species.
(neat): 2942, 2120, 1755 cm . H NMR (300 MHz, CDCl
3
): δ
J . Org. Chem, Vol. 68, No. 13, 2003 5263

Sridhar et al.
5
.35 (d, 1H, J ) 3.3 Hz), 5.21 (t, 1H, J ) 9.0 Hz), 5.11 (dd, 1H,
2.10 (s, 3H), 2.05 (s, 3H), 2.03 (s 3H), 1.98 (s, 3H). 13C NMR
J ) 8.1 Hz, J ) 10.2 Hz), 4.96 (dd, 1H, J ) 3.3 Hz, J ) 10.2
(75 MHz, CDCl
68.4, 62.3, 54.8, 23.2, 20.7, 20.6, 20.5. EIMS m/z: 369 (M
23). HRMS: calcd for C14 , 369.1274; found, 369.1288.
Da ta for Hep ta -O-a cetyl-â-D-la ctop yr a n osyla m in e (13).
3
): δ 171.5, 170.8, 170.7, 169.3, 86.3, 73.3, 72.7,
+
Hz), 4.86 (t, 1H, J ) 9.0 Hz), 4.64 (d, 1H, J ) 8.7 Hz), 4.48-
+
4
.53 (m, 2H), 4.05-4.16 (m, 3H), 3.88, (t, 1H, J ) 6.9 Hz), 3.82
22 2 8
H N O
(t, 1h, J ) 9.9 Hz), 3.71 (ddd, 1H, J ) 1.5 Hz, J ) 4.8 Hz, J )
-
1
1
9
2
1
7
2
.9 Hz), 2.15 (s, 3H), 2.14 (s, 3H), 2.08 (s, 3H), 2.07 (s, 3H),
IR (neat): 3410, 2943, 1746 cm
.
H NMR (300 MHz,
1
3
.05 (bs, 6H), 1.97 (s, 3H). C NMR (75 MHz, CDCl
3
): δ 170.3,
CDCl ): δ 5.35 (d, 1H, J ) 2.7 Hz), 5.23 (t, 1H, J ) 9.3 Hz),
3
70.1, 170.0, 169.6, 169.5, 169.0, 101.1, 87.7, 75.7, 74.7, 72.5,
0.9, 70.9, 70.7, 69.0, 66.5, 61.7, 60.8, 20.8, 20.7, 20.6, 20.6,
0.6, 20.6, 20.5.
5.11 (dd, 1H, J ) 7.8 Hz, J ) 10.2 Hz), 4.95 (dd, 1H, J ) 3.3
Hz, J ) 10.2 Hz), 4.73 (t, 1H, J ) 9.3 Hz), 4.47 (d, 1H, J ) 8.1
Hz), 4.46 (m, 1H), 4.04-4.17 (m, 4H), 3.87 (t, 1H, J ) 6.9 Hz),
3.73 (t, 1H, J ) 9.6 Hz), 3.59 (m, 1H), 2.16 (s, 3H), 2.13 (s,
Da t a for 2,3,4-Tr i-O-a cet yl-6-a zid o-6-d eoxy-â-D-glu -
2
0
-1
13
cop yr a n osyl Azid e (18). IR (neat): 2942, 2119, 1756 cm
.
3H), 2.07 (s, 6H), 2.05 (bs, 6H), 1.96 (s, 3H). C NMR (75 MHz,
1
H NMR (300 MHz, CDCl
3
): δ 5.22 (t, J ) 9.3 Hz, 1H), 5.05
CDCl ): δ 170.5, 170.4, 170.3, 170.1, 170.1, 169.6, 169.0, 101.0,
3
(
t, J ) 9.9 Hz, 1H), 4.96 (t, J ) 9.0 Hz, 1H), 4.67 (d, J ) 9.0
84.6, 73.6, 72.9, 72.4, 70.9, 70.6, 69.0, 66.5, 62.3, 60.7, 20.9,
+
Hz, 1H), 3.75-3.81 (m, 1H), 3.37-3.43 (m, 2H), 2.08 (s, 3H),
2
8
20.8, 20.8, 20.6, 20.6, 20.6, 20.6, 20.4. EIMS m/z: 658 (M
+
.04 (s, 3H), 2.02 (s, 3H). 13C NMR (75 MHz, CDCl
7.7, 75.7, 72.4, 70.5, 68.9, 50.9, 20.6, 20.5; EIMS m/z: 314
): δ 169.3,
3
23). HRMS: calcd for C H37NO17 + Na, 658.1959; found,
2
6
658.1944.
+
(M
- 42). Anal. Calcd for C12
Found: C, 40.37; H, 4.69.
Da t a for 3,4,6-Tr i-O-a cet yl-2-a zid o-2-d eoxy-â-D-glu -
16 6 7
H N O : C, 40.45; H, 4.53.
Da ta for com p ou n d 2,3,4-Tr i-O-a cetyl-6-a zid o-6-d eoxy-
â-D-glu cop yr a n osyla m in e (19). IR (neat): 3410, 2104, 1751
-1
1
cm . H NMR (300 MHz, CDCl
3
): δ 5.24 (t, J ) 9.9 Hz, 1H),
.97 (t, J ) 9.9 Hz, 1H), 4.82 (t, J ) 9.3 Hz, 1H), 4.21 (d, J )
.7 Hz, 1H), 3.63-3.69 (m, 1H), 3.31-3.32 (m, 2H), 2.07 (s,
2
2
-1
1
cop yr a n osyl Azid e (20). IR (neat): 2115, 1750 cm
NMR (300 MHz, CDCl ): δ 5.37 (d, J ) 1.5 Hz, 1H), 4.84 (dd,
J ) 2.7, 10.5 Hz, 1H), 4.62 (d, J ) 8.7 Hz, 1H), 4.10-4.21 (m,
2
2
1
. H
4
8
3
1
2
4
3
13
H), 2.04 (s, 3H), 2.01 (s, 3H). C NMR (75 MHz, CDCl
70.22, 170.19, 169.6, 84.9, 73.8, 73.0, 71.9, 69.9, 51.4, 20.8,
0.6. EIMS m/z: 331(M + 1). Anal. Calcd for C12
3.64; H, 5.49. Found: C, 43.57; H, 5.46.
3
): δ
H), 3.96 (t, J ) 6.6 Hz, 1H), 3.59 (dd, J ) 9.3, 10.2 Hz, 1H)
.17 (s, 3H), 2.06 (s, 6H). 13C NMR (75 MHz, CDCl
69.9, 169.6, 89.3, 72.6, 71.4, 66.0, 61.1, 60.4, 20.6, 20.54, 20.52.
): δ 170.3,
3
+
18 4 7
H N O : C,
Gen er a l P r oced u r e for th e Red u ction of â-D-Glycosyl
Da ta for 2-Deoxy-2-a zid o-3,4,6-Tr i-O-a cetyl-â-D-glyco-
Azid es. (a) The azides 2, 4, 6, 8, 10, 12, or 14 (1 mmol) and
tetrathiomolybdate 1 (1 mmol) were stirred at room temper-
ature (28 °C) in acetonitrile/ethanol (1:1, 3 mL) for the time
indicated in the table. After completion of the reaction (TLC),
the solvent was evaporated under reduced pressure. The black
residue was extracted with CH
filtered through a pad of Celite, and the solvent was evapo-
rated. The residue was purified on silica gel column (CHCl
MeOH, 9:1) to furnish amines 3, 5, 7, 9, 11, 13, or 15,
respectively. (b) Similar experiments under sonication (CH
-1 1
p yr a n osyla m in e (21). IR (neat): 3343, 2114, 1747 cm . H
NMR (300 MHz, CDCl ): δ 5.34 (d, J ) 2.7 Hz, 1H), 4.84 (dd,
J ) 1.8, 10.8 Hz, 1H), 4.07-4.10 (m, 3H), 3.86 (t, J ) 6.6 Hz,
H), 3.45 (dd, J ) 10.2, 9.6 Hz, 1H), 2.16 (s, 3H), 2.05 (s, 6H).
3
1
13
C NMR (75 MHz, CDCl
1.5, 66.8, 62.2, 61.7, 20.7, 20.67, 20.63. CIMS m/ z: 331 (M
1). Anal. Calcd for C12 : C, 43.64; H, 5.49. Found:
C, 43.77; H, 5.76.
Da ta for Com p ou n d 23. IR (neat): 3370, 1747 cm- . H
NMR (300 MHz, CDCl ): δ 5.08 (bs, 1H), 4.83 (bs, 1H), 4.57
bs, 3H), 3.18 (m, 2H), 2.17 (s, 3H), 2.15 (s, 3H), 2.12 (s, 3H).
3
): δ 170.4, 17.0, 169.8, 85.6, 72.2,
2
Cl
2
/ether (1:10, 4 × 5 mL) and
+
7
+
18 4 7
H N O
3
/
1
1
3
-
3
CN/EtOH, ultrasonic cleaning bath, 25 kHz) furnished prod-
ucts 3, 5, 7, 9, 11, 13, or 15, respectively, in a shorter period
of time (Table 1).
(
1
3
C NMR (75 MHz, CDCl
3
): δ 170.06, 169.85, 169.15, 87.35,
7
3.55, 71.50, 71.25, 69.91, 45.72, 21.05, 21.03, 20.96. EIMS
Da ta for 2,3,4,6-Tetr a -O-a llyl-â-D-glu cop yr a n osyla m in e
+
m/ z: 642 (M + 2). Anal. Calcd for C24
H, 5.66. Found: C, 44.66; H, 5.52.
36 2 14 2
H N O S : C, 44.99;
-
1
1
(
9). IR (neat): 3431, 1747, 1624 cm ; H NMR (300 MHz,
CDCl
3
): δ 6.03-5.85 (m, 4H), 5.312-5.14 (m, 8H), 4.41-4.21
(m, 5H), 4.13-3.98 (m, 4H), 3.69-3.55(m, 2H), 3.40-3.33 (m,
H), 2.97 (t, 1H, J ) 7.5 Hz); 1 C NMR (75 MHz, CDCl
3
Ack n ow led gm en t. The authors thank the Volks-
wagen Foundation, Germany, for financial support of
this investigation. P.R.S. thanks CSIR, New Delhi, for
a senior research fellowship.
3
1
8
3
): δ
35.2, 135.0, 134.8, 134.5, 117.4, 117.1, 116.8, 116.5, 85.9, 85.2,
2.7, 77.65, 75.5, 74.3, 73.7, 73.6, 72.5, 69.0; EIMS: m/ z: 340-
+
(
M +1). Analysis:calcd for C18
H
29NO
5
:
C, 63.69; H, 8.61.
Found: C, 63.09; H, 8.33.
Da ta for 2-Aceta m id o-2-d eoxy-3,4,6-tr io-O-a cetyl-â-D-
Su p p or t in g In for m a t ion Ava ila b le: 1H and 13C NMR
spectra for compounds 8-13, 18-21, and 23. This material is
available free of charge via the Internet at http://pubs.acs.org.
1
8
3
glu cop yr a n osyla m in e (11). IR (neat): 3330(NH), 2105 (N )
-
1 1
cm . H NMR (300 MHz, CDCl
3
): δ 5.84 (d, 1H, J ) 9.3 Hz),
.03-5.17 (m, 2H), 4.22 (dd, 1H, J ) 4.8 Hz, J ) 12.3 Hz),
.02-4.15 (m, 2H), 3.98 (d, 1H, J ) 9 Hz), 3.62-3.68 (m, 1H),
5
4
J O0266947
5
264 J . Org. Chem., Vol. 68, No. 13, 2003