Carbon Dioxide → ortho-aminophenylbenzoxazole

Participants

Reaction Steps

An intimate mixture of 2-aminophenol (109.13 g) and isatoic anhydride (203.9 g) was heated at 140° C. for 2 to 4 h until the formation of carbon dioxide ceased. Then the mixture was placed under vacuum (at a constant pressure of 50 mmHg) and the heating was continued at 180° C. for 3 to 4 h until the formation of water ceased. The melt was poured into a porcellanic mortar and, after cooling, the cold material was pestled, then boiled in a solution of caustic soda (12 g) in water (3.5 L) for 2 to 3 h. After cooling, the precipitate was isolated by filtration, and washed with cold water until the pale blue fluorescence disappeared in the washings. The precipitate was dried at 80° C. to afford 2-(benzo[d]oxazol-2-yl)phenylamine (180 to 185 g). The product was used without further purification in the next stage of preparation.

Provenance & Evidence