204 Gao et al.
added dropwise with stirring at room temperature
for 24 h. Pyridine and excess acetic anhydride were
evaporated under reduced pressure, and the residue
was poured into water. The mixture was extracted
with chloroform three times (3 × 100 mL). The com-
bined organic phases were washed with saturated
sodium bicarbonate solution and dried over anhy-
drous sodium sulfate. The solution was evaporated,
and the purification was carried out on a silica gel
column, using a solution of dichloromethane and
methanol (100:3) to afford compound 2 (30.2 g,
yield 95%). 1H NMR (300 MHz, CDCl3), δ: 6.19
(1H, d, J = 3.9 Hz, H-1), 5.41 (1H, dd, J1 = 9.6 Hz,
J2 = 9.9 Hz, H-2), 5.01–4.92 (2H, m, H-3, 4), 3.87
(1H, dd, J1 = 6.0 Hz, J2 = 5.4 Hz, H-5), 3.65 (1H, t,
H-5, J = 10.1 Hz), 2.11 (3H, s, CH3), 2.10 (3H, s,
CH3), 1.99 (3H, s, CH3), 1.98 (3H, s, CH3). 13C NMR
(75 MHz, CDCl3), δ: 170.08, 169.74, 169.29, 168.97,
89.27, 69.52, 69.38, 68.68, 60.67, 20.84, 20.70, 20.64,
20.46. MS (ESI): 318 (M, 100%), 319 (M + 1, 15%).
Anal. Calcd for C13H18O9: C, 49.06; H, 5.70; O, 45.24.
Found: C, 48.94; H, 5.73.
bicarbonate solution, stirred at room temperature
for 1 h, and the pH of solution was adjusted to
6 with dilute HCl. The mixture was extracted with
dichloromethane three times (3 × 50 mL), and the
organic solution was dried over anhydrous sodium
sulfate, evaporation of the solvent to obtain the al-
most pure yellowish liquid product 5 (10.5 g) in
about 93% yield. The compound 5 was used directly
in the following steps because of its instability on
silica gel column.
Synthesis of 1-S-Dimethylarsino-2,3,4-tri-O-
acetyl-β-D-xylopyranose (6a)
1-Thiol-2,3, -tri-O-acetyl-β-D-xylopyranose 5 (5.0 g,
0.017 mol) and triethylamine (2.0 g) were dis-
solved in 30 mL of dichloromethane and placed
into a 100-mL flask and immersed an ice-bath.
Dimethylchloroarsine (2.5 g, 0.018 mol) was dis-
solved in 20 mL of dichloromethane and added to
the flask while stirring vigorously. Stirring was con-
tinued for 2 h, and the temperature allowed rise to
room temperature. The solution was poured into a
separatory funnel, washed with water (2 × 50 mL).
The organic layer was dried over anhydrous sodium
sulfate. After removal of the dichloromethane, the
residue was purified using flash column chromatog-
raphy, diluted with solution of dichloromethane and
methanol (100: 3 in volume), the product 6a (5.0 g,
yield 74.6%) was obtained. 1H NMR (300 MHz,
CDCl3), δ: 5.70–4.90 (3H, m, H-1,2,3), 4.58–4.63 (1H,
m, H-4), 4.22–4.16 (1H, m, H-5), 3.38–3.43 (1H, m,
H-5ꢁ), 2.05 (3H, s, CH3), 2.04 (3H, s, CH3), 2.03 (3H,
s, CH3), 1.37–1.34 (6H, m, As(CH3)2). 13C NMR (75
MHz, CDCl3), δ: 170.08, 169.82, 169.37, 83.70, 72.69,
71.98, 68.80, 66.17, 20.84, 20.74, 14.34, 13.76. MS
(ESI): 396 (M, 100%), 397 (M + 1). Anal. Calcd for
C13H21AsO7S: C, 39.40; H, 5.34; As, 18.91; S, 8.09.
Found: C, 38.98; H, 5.35; As, 19.22; S, 7.97.
Synthesis of 1-Bromo-2,3,4-tri-O-acetyl-α-
D-xylopyranose (3)
1,2,3,4-Tetra-O-acetyl-ß-D-xylopyranose 2 (20 g, 0.06
mol) was dissolved in 100 mL of dichloromethane
and cooled in an ice bath, 30% HBr/acetic acid (20
mL, 0.1 mol) solution was poured into mixture and
kept stirring for 30 min. The solution was poured
into 300 mL of ice water. The organic phase was
separated and washed with a weak base solution to
pH ∼7 and dried over anhydrous sodium sulfate.
The solvent was evaporated at reduced pressure, and
the residue was dissolved in acetone. The acetone
was evaporated slowly in lower temperature to get
the pure crystalline compound 3 (16.3 g, yield 80%).
1H NMR (300 MHz, CDCl3), δ: 5.55 (1H, t, J = 9.9
Hz, H-1), 5.08–4.97 (2H, m, H-2, 3), 4.76 (1H, dd,
J1 = 3.9 Hz, J2 = 6.0 Hz, H-4), 4.05 (1H, dd, J1 = 6.0
Hz, J2 = 5.4 Hz, H-5), 3.87 (1H, t, J = 10.1 Hz, H-
5ꢁ), 2.12–2.03 (9H, m, 3×CH3). 13C NMR (75 MHz,
CDCl3), δ: 169.53, 169.44, 87.48, 70.69, 69.35, 67.92,
62.40, 20.64, 20.63, 20.60. HRMS (ESI): Calcd for
C11H15O7Br, 338.0001; found 338.0006.
Synthesis of 1-S-Diethylarsino-2,3,4-tri-O-acetyl-
β-D-xylopyranose (6b)
Refer to the synthesis of 1-S-dimethylarsino-2,3,4-
tri-O-acetyl-β-D-xylopyranose 6a. 1H (300 MHz,
CDCl3), δ: 5.20–4.85 (3H, m, H1,2,3), 4.58 (1H, d,
J = 5.7 Hz, H-4), 4.16 (1H, dd, J1 = 5.1 Hz, J2 = 6.3
Hz, H-5), 3.33 (1H, dd, J1 = 9.6 Hz, J2 = 1.5 Hz, H-
5ꢁ), 2.01 (3H, s, CH3), 2.02 (3H, s, CH3), 2.03 (3H,
s, CH3), 1.76 (4H, m), 1.20 (6H, dd, J1 = 7.5 Hz,
J2 = 6.9 Hz, As(CH3)2). 13C NMR (75 MHz, CDCl3),
δ: 170.15, 169.84, 169.40, 83.94, 72.85, 72.23, 68.88,
66.10, 20.97, 20.77, 20.64, 10.22. MS (ESI): 424 (M,
100%), 425 (M + 1). Anal. Calcd for C15H25AsO7S: C,
Synthesis of 1-Thiol-2,3,4-tri-O-acetyl-β-D-
xylopyranose (5)
1-Bromo-2,3,4-tri-O-acetyl-α-D-xylopyranose 3 (13.5
g, 0.04 mol) and thiourea (3.5 g, 0.046 mol) were
dissolved in 50 mL of acetone, stirred at reflux for
1 h. After refluxing, evaporation of acetone, the
residue was poured into 50 mL of saturated sodium
Heteroatom Chemistry DOI 10.1002/hc