J. Lalot et al. / Carbohydrate Research 338 (2003) 2241ꢀ
/
2245
2243
Table 1
1
3
C NMR data
Compound Chemical shifts d (ppm)
C-1 C-2 C-3 C-4 C-5 Other signals
170.4 72.8 75.0 78.4 31.8 169.9 (COCH
a
2
3
4
4
5
5
7
8
9
9
1
1
b
3
); 20.9ꢀ
/
20.6 (COCH
3
)
a
170.1 72.9 74.9 78.2 31
95.2 77.2 78.1 79.4 33.7 170.5; 170.3 (COCH
170.0; 168.0 (COCH ); 20.8ꢀ
/
20.5 (COCH ); 194.6 (SCOCH ); 30.8 (SCOCH )
3
3
3
3
a
a
b
b
a
a
b
a
b
3
); 21.2, 20.8 (COCH
3
); 195.3 (SCOCH
3
); 30.6 (SCOCH
3
)
100.6 823
78.8 74.2 74.2 68.4 29.8 -
79.1 81.0 31.4 170.5; 170.3.0 (COCH
3
); 21.9ꢀ20.8 (COCH
/
3
); 195.3 (SCOCH
3
3
); 30.6 (SCOCH )
74.0 71.5 70.0 69.8 29.1 -
173.8 72.6 71.5 77.6 29.6 170.1, 169.8 (COCH
b
3
); 21.8; 20.9 (COCH
3
)
a
170.1 71.4 72.8 77.3 28.5 169.7, 168.9 (COCH ); 20.9, 20.7 (COCH ); 194.0 (SCOCH ); 30.8 (SCOCH )
3
3
3
3
3
3
a
a
a
b
94.4 77.8 75.3 79.6 29.3 170.2; 170.0 (COCH
101.0 81.7 75.8 75.3 28.3 170.6; 170.5 (COCH
74.6 78.0 76.9 73.5 30.0 -
); 21.3ꢀ
); 21.3, 21.0 (COCH
/
21 (COCH ); 195.7 (SCOCH
3
3
3
); 30.7 (SCOCH )
3
3 3
); 195.3 (SCOCH ); 30.7 (SCOCH )
b
b
0a
0b
73.5 75.8 74.0 73.5 27.4 -
a
3
In CDCl .
b
2
In D O.
stirred, under an inert atmosphere, at rt for 24 h. Then
MeOH was added and the solution was kept for 30 min
and concentrated. The crude material was diluted with
CH Cl and washed with water. The CH Cl extracts
C H BrO : C, 36.63; H, 3.76; Br, 27.08. Found: C,
9 11 6
36.67; H, 3.81; Br, 27.32.
2
2
2
2
1.7. 2,3-Di-O-acetyl-5-S-acetyl-5-thio-
lactone (8)
D-xylono-1,4-
were dried (MgSO ), filtered and concentrated. Column
4
chromatography (4:1, hexanesꢀ/EtOAc) of the residue
afforded 4 (0.413 g, 82%) as a colourless syrup: R 0.34
f
To a soln of 7b (0.5 g, 1.7 mmol) in N,N-dimethylfor-
mamide was added potassium thioacetate (0.23 g, 2
mmol) and the reaction was treated as for 2b to give 8
(
1
5
3:2 hexanesꢀ
/
EtOAc); [a]D
ꢁ
/
328 (a/b 7:3, NMR) (c
.83, CH Cl ). Anal. Calcd for C H O S: C, 45.20; H,
.52. Found: C, 45.23; H, 5.60.
2
2
11 16
7
(
0.452 g, 92%) as a colourless syrup: Rf 0.54 (3:2
hexanesꢀEtOAc); [a]D 838 (c 1.69, CH Cl ). Anal.
Calcd for C H O S: C, 45.51; H, 4.86. Found: C,
/
ꢁ
/
2
2
1
1
14
7
1
.5. 5-Thio-D-arabinopyranose (5)
45.55; H, 4.90.
To a soln of the thioacetate (4) (0.5 g, 1.71 mmol) in
MeOH (5 mL) was added NaOMe (0.092 g, 6 equiv).
The mixture was stirred for 3 h at rt. The solution was
passed through an ion exchange resin column (Dowex
1
.8. 2,3-Di-O-acetyl-5-S-acetyl-5-thio-D-xylopyranose
(9)
5
0ꢃ
/
8-100) filtered and concentrated. Column chroma-
2,3-di-O-acetyl-5-S-acetyl-D-xylono-1,4-lactone (8) (0.5
g, 1.72 mmol) was reduced by disiamylborane as
described for 3 to give 9 (0.391 g, 78%) as a colourless
tography (9:1, CH Cl ꢀ
5
/MeOH) of the residue afforded
2
2
(0.20 g, 71%) as a colourless syrup: Rf 0.61 (4:1
CH Cl ꢀ 458 (a/b 3:7, NMR) (c 1.02,
/
MeOH); [a]D
ꢁ
/
2
2
syrup: R 0.35 (3:2 hexanesꢀ
2:3, NMR) (c 0.7, CH Cl ). Anal. Calcd for C H O S:
C, 45.20; H, 5.52. Found: C, 45.26; H, 5.57.
/
EtOAc); [a]D
ꢁ758 (a/b
/
f
5
water), lit.: for b form [a]
ꢄ
/
2508 (c 0.6, water), mp
D
2
2
11 16
7
6
1
73ꢀ
/
175 8C. Anal. Calcd for C H O S: C, 36.13; H,
5
10
4
6
.06. Found: C, 36.18; H, 6.14.
1.9. 5-Thio-D-xylopyranose (10)
1.6. 2,3-Di-O-acetyl-5-bromo-5-deoxy-D-xylono-1,4-
lactone (7b)
The lactol (0.5 g, 1.71 mmol) was treated by NaOMe in
MeOH as described for 4 to give 10 (0.239 g, 84%) as a
Reaction of
D-xylono-1,4-lactone (6) (0.5 g, 3.4 mmol)
colourless syrup: R 0.61 (4:1 CH Cl ꢀ
/MeOH), [a]D
ꢁ
/
f
2
2
with thionyl bromide in N,N-dimethylformamide as for
, followed by acetylation with acetic anhydride gave 7b
0.496 g, 71%) as a thick liquid; R 0.60 (3:2 hexanesꢀ
1208 (a/b 1:4, NMR) (c 2.7, water), lit.: mp 122ꢀ
/
123 8C,
2020 1738
(c 1.6, water). Anal. Calcd for C H O S: C, 36.13; H,
4
a
1
(
[a]
ꢁ
/
2020
/
ꢁ
/
1788 (c 2, water); [a]
ꢁ
/
/
ꢁ
/
D
D
4
b
/
f
5
10
4
EtOAc); [a]D
ꢁ
/
628 (c 4.8, CH Cl ). Anal. Calcd for
6.06. Found: C, 36.21; H, 6.11.
2
2