反应详情

3-Bromothiophene (8.15 g, 0.05 mol), paraldehyde (2.20 g, 0.017 mol) and 4-isopropylbenzamide (1.63 g, 0.01 mol) were added to a mixture of formic acid (6 ml) and 85% phosphoric acid (3 ml) and stirred at a room temperature for four hours. Water (50 ml) was added to the reaction mixture. The mixture was extracted with chloroform (50 ml), subjected to a silica gel column chromatography (eluent: chloroform) and recrystallized from chloroform/petroleum benzine (1:2) to obtain the entitled compound (0.6 g) as a colorless plate-shape crystal. Yield: 17.0%. Melting point: 133° C.

1. extractionThe mixture was extracted with chloroform (50 ml)
2. customrecrystallized from chloroform/petroleum benzine (1:2)