Dimethylformamide → 2,7-dimethoxy-3H-phenothiazin-3-one

Participants

Reaction Steps

To a suspension of 2-methoxy-p-benzoquinone (1.15 kg) (Step 1) in methanol (8 l) was added portionwise a suspension of 2-amino-5-methoxythiophenol (from Step 2) in methanol (6 l). The reacting mixture was stirred for 15 minutes, filtered and washed with methanol (8 l). The product isolated was swished with DMF (16 l) for 2 hours, filtered and air-dried. The crude material was dissolved in hot DMF (16 l) (130°-140° C.), filtered on Celite and the filtrate cooled to room temperature. The resulting crystals were filtered, washed with methanol (8 l) and air-dried to afford the title compound (70.3 g), m.p. 237°-238° C.

Provenance & Evidence