Diphenylacetaldehyde → 5-fluoro-3-hydroxy-N-(2,2-diphenylethenyl)benzo[b]thiophene-2-carboxamide

Participants

Reaction Steps

To a solution of 5-fluoro-3-hydroxybenzo[b]thiophene-2-carboxamide (400 mg, 1.89 mmol) in hot toluene (35 ml) were added diphenylacetaldehyde (577 mg, 2.84 mmol) and p-toluenesulfonic acid monohydrate (25 mg). The reaction mixture was stirred at reflux temperature for 2 hours with azeotropic removal of water, cooled, and evaporated under diminished pressure. The solid obtained was recrystallized from diethyl ether-hexane to yield 604 mg (82%) of 5-fluoro-3-hydroxy-N-(2,2-diphenylethenyl)benzo[b]thiophene-2-carboxamide, m.p. 186°-189° C.

Provenance & Evidence