反应详情

A mixture of 5 g of 7-(propionamido)-2-(4-carboxyphenyl)-4H-3,1-benzoxazine-4-one, 50 ml of dimethylformamide, 10 ml of water and 8 ml of triethylamine was heated at 80°-90° C. for a period of 10 hours. After being allowed to cool, the mixture was treated with dilute hydrochloric acid to adjust its pH between 2 and 3. The precipitating crystal was filtered, washed with water, and recrystallized from isopropyl alcohol to produce 4.1 g of 2-(4-carboxybenzamido)-4-propionamidobenzoic acid having a melting point in the range of 284° to 286° C. (decompose).

1. temperaturewas heated at 80°-90° C. for a period of 10 hours
2. temperatureto cool
3. filtrationThe precipitating crystal was filtered
4. washwashed with water
5. customrecrystallized from isopropyl alcohol