反应详情

A mixture of 2-butyl-1,2,4-thiadiazolo[4,5-a]benzimidazole-3(2H)-one (6.0 g, 24.3 mmole) and benzoyl cyanide (6.36 g, 48.5 mmole) in 80 mL of dichloromethane was stirred at room temperature for 24 h. The precipitate was filtered and washed with dichloromethane. The crude product was recrystallized from acetone to give 6.48 g (96%) of 3-(oxophenylmethyl)-1,2,4-thiadiazolo[4,5-a]benzimidazole as yellow crystals: mp 190-191° C.; 1H NMR (CDCl3)δ 8.35 (d, 3H), 7.82 (d, 1H), 7.73 (t, 1H), 7.59 (t, 2H), 7.50 (t, 1H), 7.36 (t, 1H) ppm; 13C NMR (CDCl3)δ 180.86, 163.69, 150.82, 146.70, 134.79, 134.34, 131.22 (2C), 129.46 (2C), 128.74, 125.82, 122.27, 119.49, 115.23 ppm; IR (KBr)ν 1671 cm-1 ; HRMS calcd for C15H9N3OS: 279.0466, found: 279.0475. Anal. Calcd for C15H9N3OS: C, 64.50;H, 3.25; N, 15.04. Found: C, 63.93;H, 3.10; N, 14.53.

1. filtrationThe precipitate was filtered
2. washwashed with dichloromethane
3. customThe crude product was recrystallized from acetone