Ethanol → HCID 23336681, compound

Participants

Reaction Steps

6-Hydroxy-4-oxo-4H-1-benzothiopyran-2-carboxylic acid (20 g) was heated in ethanol (500 ml) at reflux overnight with a few drops of concentrated sulphuric acid as catalyst. The solution was evaporated to small volume and flooded with water. The resulting solid was filtered off, washed with saturated sodium bicarbonate solution, water and dried. The product was recrystallised from ethanol as a yellow solid (13.7 g) 61%. m.p. 216°-217°.

Provenance & Evidence