Thionyl Chloride → 7-chloro-3-(4-chlorophenyl)-2,3-dihydro-4H-1-benzothiopyran-4-one

Participants

Reaction Steps

A solution of 4-chlorophenyl-α-[(3-chlorophenyl)thiomethyl]acetic acid (2.0 g), thionyl chloride (5 ml) and N,N-dimethylformamide (one drop) in hexane (10 ml) was heated at reflux for 1 hour. The reaction mixture was concentrated under reduced pressure. To the resulting residue, dichloroethane (13 ml) was added under a stream of nitrogen gas and anhydrous aluminum chloride (1.0 g) was added in small portions at a temperature below 0° C. The reaction was allowed to proceed at 0° C. for 1 hour, and the reaction mixture was poured into ice-water and extracted with methylene chloride (100 ml, 50 ml×2). The extract was dried over anhydrous magnesium sulfate and concentrated to give 7-chloro-3-(4-chlorophenyl)-2,3-dihydro-4H-1-benzothiopyran-4-one.

Provenance & Evidence