´
E. Bozo´ et al. / Carbohydrate Research 337 (2002) 1351–1365
1363
and 64b in a ratio of 2:4:1:1 and was submitted to
column chromatography (solvent C).
2.90–2.45 (m, 4 H, S-CH2CH3), 2.15, 2.09, 2.08, 2.06
and 2.05 (5 s, 5×3 H, OAc) 1.33 and 1.23 (2 t, 2×3
H, S-CH2CH3); 13C NMR: l 72.1, 70.0, 68.4, 68.3
(C-2,3,4,5), 61.4 (C-6), 50.7 (C-1)
Concentration of the first fraction (Rf 0.4) gave a
syrup (1.6 g, 19%) which according to GLC and NMR
1
contained 64a and 64b in a ratio of ꢀ1:1. H NMR
Concentration of the second fraction gave 58 (23.1 g,
(CDCl3): 64a l 6.44 (d, J1,2 4.4, 1 H, H-1), 5.52 (dd, J2,3
3.3, J3,4 4.9 Hz, 1 H, H-3), 5.20 (ddd, J4,5 5.1, J5.6a 6.8,
J5.6b 3.4 Hz, 1 H, H-5), 5.18 (dd, 1 H, H-2), 4.44 (dd, 1
H, H-4), 3.54 (dd, J6a,6b 14.0 Hz, 1 H, H-6b), 3.02 (dd,
1 H, H-6a), 2.33 (s, 3 H, SAc), 2.12–1.96 (OAc); 13C
NMR: l 93.4 (C-1), 30.2 (S-Ac), 29.9 (C-6), 64b l 6.10
(s, J1,2 ꢀ0, 1 H, H-1), 5.39 (d, J2,3 ꢀ0, J3,4 4.6 Hz, 1
H, H-3), 5.28 (ddd, J4,5 5.1, J5.6a 6.4, J5.6b 3.4 Hz, 1 H,
H-5), 5.10 (s, 1 H, H-2), 4.47 (dd, 1 H, H-4), 3.60 (dd,
J6a,6b 14.0 Hz, 1 H, H-6b), 3.00 (dd, 1 H, H-6a), 2.33 (s,
3 H, SAc), 2.12–1.96 (OAc); 13C NMR: l 98.6 (C-1),
30.4 (C-6), 30.2 (S-Ac). Anal. Calcd for C16H22O10S: C,
47.29; H, 5.46; S, 7.89. Found: C, 47.42; H, 5.62; S,
7.53.
76%) as a syrup, [h]D +9°. Lit.16 [h]D +8° (c 4,
1
CHCl3). H NMR (CDCl3): l 7.78 and 7.38 (2 d, 4 H,
aromatic) 5.71 (dd, J2,3 7.6, J3,4 2.6 Hz, 1 H, H-3), 5.38
(dd, J4,5 8.1 Hz, 1 H, H-4), 5.23 (dd, J1,2 4.2, 1 H, H-2),
5.01 (ddd, J5.6a 4.2, J5.6b 2.9 Hz, 1 H, H-5), 4.18 (dd,
J6a,6b 11.2 Hz, 1 H, H-6b), 4.11 (d, 1 H, H-1), 4.10 (dd,
1 H, H-6a), 2.85–2.45 (m, 4 H, S-CH2CH3), 2.45 (s, 3
H, TsCH3), 2.09, 2.07, 2.02 and 2.01 (4 s, 4×3 H,
OAc) 1.29 and 1.23 (2 t, 2×3 H, S-CH2CH3); 13C
NMR: l 72.0, 69.8, 67.9, 67.8 (C-2,3,4,5), 66.4 (C-6),
50.6 (C-1).
2,3,4,5-Tetra-O-acetyl-6-S-acetyl-D-glucose diethyl
dithioacetal (59).—To a stirred solution of 58 (12.2 g,
20 mmol) in acetone (250 mL), KSAc (2.96 g, 26 mmol)
was added and the slurry was boiled for 5 h when
according to TLC the reaction was completed. The
residue of the concentrated mixture was dissolved in
CHCl3, washed with water, dried and concentrated to
give 59 (10 g, 98%) as a syrup. [h]D +25°. Anal. Calcd
for C20H32O9S3: C, 46.86; H, 6.29; S, 18.76. Found: C,
The second fraction (Rf 0.35) afforded on concentra-
tion 56 (1,7 g, 20.5%): mp 95–97 °C (ether–hexane),
1
[h]D −59°; H NMR (CDCl3): l 6.01 (d, J1,2 6.8, 1 H,
H-1), 5.53 (dd, J2,3 4.6, J3,4 8.5 Hz, 1 H, H-3), 5.40–
5.27 (m, 2 H, H-4,5), 5.24 (dd, 1 H, H-2), 2.98 (d,
J5,6aꢀJ5,6b 5.8 Hz, 2 H, H-6a,6b), 2.12, 2.11, 2.11, 2.10,
2.04 (5 s, 5×3 H, OAc); 13C NMR: l 75.9, 74.9, 70.7,
69.6, 68.9 (C-1,2,3,4,5), 28.0 (C-6). Anal. Calcd for
C16H22O10S: C, 47.29; H, 5.46; S, 7.89. Found: C, 47.21;
H, 5.45; S, 7.78.
1
46.72; H, 6.11; S, 18.52. H NMR (CDCl3): l 5.78 (dd,
J2,3 7.1, J3,4 3.2 Hz, 1 H, H-3), 5.35 (dd, J4,5 7.1 Hz, 1
H, H-4), 5.29 (dd, J1,2 4.6, 1 H, H-2), 5.01 (ddd, J5.6a
6.6, J5.6b 3.2 Hz, 1 H, H-5), 4.07 (d, 1 H, H-1), 3.33 (dd,
J6a,6b 14.6 Hz, 1 H, H-6b), 2.99 (dd, 1 H, H-6a),
2.90–2.40 (m, 4 H, S-CH2CH3), 2.33 (s, 3 H, SAc),
2.16, 2.09, 2.05 and 2.03 (4 s, 4×3 H, OAc) 1.32 and
1.23 (2 t, 2×3 H, S-CH2CH3); 13C NMR: l 71.9, 70.1,
69.9, 69.2 (C-2,3,4,5), 50.8 (C-1), 29.0 (C-6).
The third fraction (Rf 0.30) gave on concentration 55
1
(0.58 g, 7%) as a syrup, [h]D +109° H NMR (CDCl3):
l 6.05 (d, J1,2 2.9, 1 H, H-1), 5.62 (dd, J2,3 9.3, J3,4 7.6
Hz, 1 H, H-3), 5.48–5.38 (m, 2 H, H-4,5), 5.35 (dd, 1
H, H-2), 3.18 (dd, J5,6b 8.1, J6a,6b 15.1 Hz, 1 H, H-6b),
2.86 (dd, J5,6a 4.6 Hz, 1 H, H-6a), 2.18, 2.13, 2.05, 2.04,
2.02 (5 s, 5×3 H, OAc); 13C NMR: l 74.7, 71.1, 71.0,
70.4, 67.8 (C-1,2,3,4,5), 26.8 (C-6). Anal. Calcd for
C16H22O10S: C, 47.29; H, 5.46; S, 7.89. Found: C, 47.39;
H, 5.65; S, 7.62.
1,2,3,4-Tetra-O-acetyl-6-S-acetyl-D-glucopyranose
(66).—To a solution of a 1:1 a,b-anomeric mixture of
the furanose compound 64 (3.2 g) in MeOH (30 mL), 3
M methanolic NaOMe (3.5 mL) was added at rt. The
mixture was neutralised after 30 min with solid CO2
and kept for 20 h at rt. The residue obtained on
concentration was dissolved in pyridine (15 mL) and
Ac2O (10 mL) was added. After 20 h at rt, the mixture
was processed by the usual way to give on concentra-
tion of the CH2Cl2 solution a syrup (2.75 g, 86%)
which, according to NMR spectroscopy and GLC mea-
surements, contained 66a and 66b in a ratio of ꢀ1:1.
After column chromatography (solvent B), the same
mixture solidified and was filtered with ether–hexane
(2.4 g, 75%), mp 88–92 °C (ether–hexane); Rf 0.45
2,3,4,5,6-Penta-O-acetyl- (57) and 2,3,4,5-tetra-O-
acetyl-6-O-p-toluenesulfonyl-
D
-glucose diethyl dithioac-
etal (58).—To a stirred solution of
D
-glucose diethyl
dithioacetal (14.3 g, 50 mmol), TsCl (10.5 g, 55 mmol)
was added at 0 °C. After 30 min the temperature was
raised to 20 °C, after 20 min the mixture was cooled
with ice and Ac2O (50 mL) was added. The mixture was
kept at rt overnight to give after usual processing a
syrup (30 g) which was submitted to column chro-
matography using solvent C for elution.
1
Concentration of the first fraction gave 57 (2.3 g,
9.2%), mp 43–45 °C (EtOH–water), Rf 0.3 (solvent C).
(solvent B). H NMR (CDCl3): 66a l 6.26 (d, J1,2 3.6,
1 H, H-1), 5.43 (dd, J2,3 10.2, J3,4 9.5 Hz, 1 H, H-3),
5.05 (dd, 1 H, H-2), 5.01 (dd, J4,5 10.0 Hz, 1 H, H-4),
4.02 (dd, J5,6bꢀJ5,6a 4.4 Hz, 1 H, H-5), 3.18 (d, 2 H,
H-6a,6b), 2.33 (s, 3 H, SAc), 2.17, 2.08, 2.01, 2.00 (4 s,
4×3 H, OAc); 13C NMR: l 88.8 (C-1), 70.6, 69.8, 69.7,
69.1 (C-2,3,4,5), 29.6 (C-6), 66b l 5.68 (d, J1,2 8.0, 1 H,
1
Lit.15 mp 45–47 °C. H NMR (CDCl3): l 5.76 (dd, J2,3
7.3, J3,4 2.9 Hz, 1 H, H-3), 5.43 (dd, J4,5 8.1 Hz, 1 H,
H-4), 5.28 (dd, J1,2 4.2, 1 H, H-2), 5.06 (ddd, J5.6a 4.8,
J5.6b 3.2 Hz, 1 H, H-5), 4.23 (dd, J6a,6b 12.7 Hz, 1 H,
H-6b), 4.11 (dd, 1 H, H-6a), 4.07 (d, 1 H, H-1),