反应详情

A mixture of 2-butyl-1,2,4-thiadiazolo[4,5-a]benzimidazole-3(2H)-one (4.0 g, 16.2 mmole) and methyl cyanoformate (2.75 g, 32.4 mmole) in 30 mL of dichloromethane was stirred at room temperature for 21 h. The precipitate was filtered and washed with dichloromethane to give 3.36 g (84%) of 3-(methoxycarbonyl)-1,2,4-thiadiazolo [4,5-a]benzimidazole as a colourless solid: mp 208-209° C.; 1H NMR (CDCl3) δ 8.61 (d, 1H), 7.82 (d, 1H), 7.51 (t, 1H), 7.31 (t, 1H), 4.17 (s, 3H) ppm; 13C NMR (CDCl3) δ 164.02, 156.51, 150.67, 140.89, 129.34, 125.93, 122.41, 119.48, 115.41, 54.04 ppm; IR (KBr) ν 1733 cm-1 ; HRMS calcd for C10H7N3O2S 233.0259, found 233.0262. Anal. Calcd. for C10H7N3O2S: C, 51.50; H, 3.02; N, 18.02. Found: C, 51.41; H, 2.89; N, 18.16.

1. filtrationThe precipitate was filtered
2. washwashed with dichloromethane