Phosphorus oxychloride → Benzoxazole

Participants

Reaction Steps

A suspension of 32.9 g (72.4 mmol) of 2-bromo-4-chloro-6-(3-cyclopentyloxy-4-methoxy-phenyl-acetylamino)-phenol in 400 ml of toluene and 39.7 ml (434 mmol) of phosphorus oxychloride was refluxed for 1.5 hours. Some solid material was filtered off and the filtrate evaporated to dryness in vacuo. The honey-like residue was suspended in 200 ml of sodium bicarbonate solution for 1 hours. The solid was collected, washed and dried at 25° C. to give 22.53 g (71.2%) of crude benzoxazole.

Provenance & Evidence