Methyl 3-mercaptopropionate → 2-(2-Methoxycarbonylethylthio)ethyl 2,3,6-tri-O-acetyl-4-O-{2,3,6-tri-O-acetyl-4-O-[2,3,4-tri-O-acetyl-6-O-(2,3,4,6-tetra-O-acetyl-alpha-D-glucopyranosyl)-alpha-D-glucopyranosyl]-alpha-D-glucopyranosyl}-beta-D-glucopyranoside

Participants

Reaction Steps

Compound 93 (4.00 g, 3.0 mmol), methyl 3-mercaptopropionate (0.546 g, 0.49 ml, 4.5 mmol) cesium carbonate (1.17 g, 3.6 mmol) and N,N-dimethylformamide (25 ml), were stirred at room temperature until 93 had been consumed (7 h; TLC; SiO2, ethyl acetate:isooctane 4:1). The solvent was removed and the residue was chromatographed (SiO2, ethyl acetate:isooctane 3:1) to give 94 (3.22 g, 78%). [α]D25 +102° (c 1.0, chloroform). 1H-NMR (CDCl3, Me4Si) δ 5.36, 5.28, 5.19 (3d, each 1H, J=3.8, 4.1 and 3.7 Hz, H1', H1", H1"'), 4.57 (d, 1H, J=7.9 Hz, H1), 3.71 (s, 3H, MeO), 2.81, 2.71, 2.61 (3t, each 2H, J=6.7 Hz, CH2 --S--CH2 and CH2 --CO). 13C-NMR (CDCl3, Me4Si) δ 100.2 (Cl), 95.8, 95.6, 95.2 (Cl', Cl", Cl"'), 75.1, 73.7, 72.6, 72.0 71.9, 71.7, 70.7, 70.3, 70.0, 69.8, 69.6, 69.3, 69.2, 68.8, 68.4, 67.3, 65.2, 63.0, 62.9, 61.7, 60.3, 51.7, 34.6, 31.3, 27.2, 20.8-20.5.

Provenance & Evidence