反应详情

A solution of 4-amino-3,4-dihydro-2H-1,4-benzoxazine (1.0 g) and 2,4-dioxopiperidine (753 mg) in absolute ethanol (40 ml) was stirred under nitrogen for 1.5 h. The solvent was removed in vacuo and the residue was dissolved in diethylene glycol (30 ml) and heated at 100° for 1 h, then at 150° for 2 h. The solution was allowed to cool, poured into water (200 ml) and extracted with dichloromethane (3×100 ml). The combined, dried organic extracts were evaporated to give a semi-solid (ca. 3 g) which was purified by FCC eluting with System A (400:10:1) to give the title compound (740 mg) as a solid, m.p. 298°-300°.

1. customThe solvent was removed in vacuo
2. dissolutionthe residue was dissolved in diethylene glycol (30 ml)
3. temperatureheated at 100° for 1 h
4. temperatureto cool
5. additionpoured into water (200 ml)
6. extractionextracted with dichloromethane (3×100 ml)
7. customdried organic extracts were evaporated