Acetic Acid → 5-Hydroxy-12H-benzo[a]phenothiazine-7,7-dioxide

Participants

Reaction Steps

To a suspension of 5-acetoxy-12H-benzo[a]phenothiazine-7,7-dioxide (6.6 g) in methanol (200 ml), kept under a nitrogen atmosphere was added 2N aqueous sodium hydroxide solution (132 ml). The mixture was stirred at room temperature for 7 minutes, then there was added 10% acetic acid (200 ml) and water (300 ml). After 10 minutes of stirring the mixture was filtered to afford the title compound (5.68 g) as a pink solid. The solid was recrystallized from THF, m.p. 334° C. (dec).

Provenance & Evidence