Hydrochloric Acid → 2-Amino-5-[(1-bromo-2-methylindolizin-3-yl)carbonyl]benzoic acid

Participants

Reaction Steps

The (5E)-5-{(2E)-2-[(1-bromo-2-methylindolizin-3-yl)carbonyl]but-2-en-1-ylidene}-4-methylidene-2-phenyl-4,5-dihydro-6H-1,3-oxazin-6-one (18.6 g; 40.4 mmol) is added portionwise to potassium hydroxide (22.7 g; 0.40 mol) in 100 mL of water and 140 mL of NMP. The reaction mixture is heated at reflux for 18 h, cooled to ambient temperature and poured into a hydrochloric acid solution (1 M). The yellow precipitate formed is filtered off and dried under vacuum to give 16.5 g (99%) of a yellow powder.

Provenance & Evidence