Acetic Acid → 6-Bromo-4-hydroxy-chromene-2-thione

Participants

Reaction Steps

A solution of 2-acetyl-4-bromophenol (20 g) and carbon disulfide (7 ml) in toluene (400 ml) was added dropwise to a suspension of potassium tert.-butoxide (31.4 g) in toluene (500 ml) at 10° C. The mixture was stirred at room temperature for 72 hours. Glacial acetic acid (35 ml) was added and the mixture evaporated under reduced pressure. The residue was treated with water (200 ml) and glacial acetic acid (20 ml) to precipitate an oily solid. Light petroleum (b.p. 40-60° C.) was added and the mixture stirred for one hour, filtered and the solid was collected and washed with light petroleum to give 6-bromo-2-mercapto-4H-1-benzopyran-4-one, m.p. 230° C. (compound 1)

Provenance & Evidence