Thiophenol → 2-(p-Nitrophenylthio)ethyl 2,3,4,6-tetra-O-acetyl-beta-D-galactopyranoside

Participants

Reaction Steps

p-Nitrothiophenol (50 mg; 0.32 mmol) was added to a suspension of sodium hydride (oil-free; 11 mg; 0.46 mmol) in dimethylformamide (3 ml) at room temperature and with stirring. 2-Bromoethyl 2,3,4,6-tetra-O-acetyl-β-D-galactopyranoside (1) (110 mg; 0.24 mmol) in dimethylformamide (3 ml) was added during 10 min to the thiophenol solution and the reaction mixture was stirred for another 75 min (TLC: SiO2, ethyl acetate:isooctane 1:1). The reaction mixture was poured into ice-cold water (20 ml) and ether (40 ml). The aqueous phase was extracted further with ether (40 ml) and the combined organic phases were washed with cold water (20 ml) and dried (sodium sulfate). Evaporation and chromatography (SiO2, ethyl acetate:isooctane 1:1) gave the title compound (25) as a light yellow oil. Yield: 80 mg (62%). [α]D23 -15.2° (c 1.1; CDCl3); 1H-NMR (CDCl3, TMS) δ 8.14, 7.36 (ABq, 4H, JAB =9.2 Hz, aromatic H), 5.40 (dd, 1H, J4,5 =1.0 Hz, H4), 5.22 (dd, 1H, J2,3 =10.5 Hz, H2), 5.01 (dd, 1H, J3,4 =3.4 Hz, H3), 4.52 (d, 1H, J1,2 =7.8 Hz, H1), 3.25 (t, 2H, J=6.5 Hz, S--CH2), 2.17, 2.05, 2.04, 1.99 (s, 3H each, CH3CO) ppm. 13C-NMR (CDCl3, TMS) δ 170.4, 170.2, 170.1, l69.4 (CO), 146.6, 145.3, 126.5, 124.1 (aromatic C), 101.4 (Cl), 70.9, 70.8, 68.5, 66.9 (C2-C5), 67.9 (CH2 --O) 61.2 (C6), 31.8 (S--CH2), 20.8, 20.7, 20.6 (CH3CO) ppm.

Provenance & Evidence