Hydrochloric Acid → 5-Nitroindoline-7-carboxylic acid

Participants

Reaction Conditions

Reaction Steps

Into concentrated hydrochloric acid (63.6 ml) was dissolved N-acetyl-7-cyano-5-nitroindoline (5.3 g), which was then subjected to stirring at 140° C. for 45 minutes. The reaction mixture was cooled to 0° C. to give deposited crystal, which was then collected by filtration. The obtained crude crystal was suspended into water (50 ml), and was rendered basic by adding 50% sodium hydroxide, and the insoluble matter was collected by filtration. After adding concentrated hydrochloric acid to the filtrate, the deposited crystal was collected by filtration and dried to give the intended compound 3.7 g (77.1%) as yellow powder. M.P.: 294°-297° C. (decomp.)

Provenance & Evidence