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 reaction mixture was stirred for 15 minutes at room temperature, filtered and the collected solid 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 through Celite and the filtrate cooled to room temperature. The crystals were filtered, washed with methanol (8 l) and air-dried to afford the title compound (703 g), m.p. 237°-238° C.

Provenance & Evidence