Sulfuric Acid → Kenpaullone

Participants

Reaction Conditions

Reaction Steps

To a suspension of 1H-[1]benzazepin-2,5(3H, 4H)-dione (0.247 g, 1.3 mmol) in acetic acid (5 ml) was added 4-bromophenylhydrazine hydrochloride (0.532 g, 2.3 mmol) and sodium acetate (0.195 g, 2.3 mmol) and stirred under argon. The mixture was heated at 70° C. for 3 hours, then cooled and concentrated sulfuric acid (0.5 ml) added, before heating at 70° C. for a further 3 hours. The slurry was poured into 10% sodium acetate aqueous solution (20 ml) and the precipitate filtered to give the title compound as a cream solid (0.367 g, yield 79.6%), mp>300° C.; 1H-NMR (DMSO-d6, 300 MHz): δ (ppm)=11.82 (s; 1 H), 10.1 (s; 1H), 7.89 (d; 1H), 7.74 (dd; 1H), 7.41-7.36 (m; 2H), 7.30-7.21 (m; 3H), 3.51 (s; 2H).

Provenance & Evidence