4H-1,4-Benzothiazin-3-one → 2H-1,4-Benzothiazin-3(4H)-one 1-oxide

Participants

Reaction Steps

A solution of 3-chloroperbenzoic acid (1.35 g, 6.6 mmol) in dry dichloromethane (40 ml) was added dropwise to an ice cooled solution of 2H-1,4-benzothiazin-3(4H)-one (1.10 g, 6.6 mmol) in dry dichloromethane (100 ml) with stirring. The reaction mixture was allowed to reach room temperature, then stirred overnight. The product was collected by filtration and washed with dichloromethane. Yield 0.54 g (45%) mp 184–6° C.

Provenance & Evidence