反应详情

Ethyl 5-cyclopropylisoxazole-4-carboxylate (203.0 g, 1.12 mole) [prepared in Step B]was added to a solution of 405 ml of glacial acetic acid plus 505 ml of 6 N HCl and the mixture was heated in an oil bath a 105°-110° C. for 3 h. After 18 h at ambient temperature the thick mixture was diluted with water, cooled in an ice bath and filtered to give 140.8 g of the title acid. Recrystallization of an aliquot from acetonitrile gave an analytical sample, mp 163°-165° C.

1. temperaturethe mixture was heated in an oil bath a 105°-110° C. for 3 h
2. temperaturecooled in an ice bath
3. filtrationfiltered