反应详情

A mixture of 640 mg ethyl 5-hydroxybenzo[a]phenazine-6-carboxylate, 6 ml of acetic anhydride and two drops of pyridine was stirred overnight and poured into water. The precipitated solid was collected by filtration and recrystallized from ethanol to give 600 mg (91.1% yield) of ethyl 5-acetoxybenzo[a]phenazine-6-carboxylate as orange needles, m.p. 195°-196° C., Anal. Calcd. (%) for C21H16N2O4 : C, 69.99; H, 4.48; N, 7.77; Found: C, 70.12; H, 4.45; N, 7.63

1. filtrationThe precipitated solid was collected by filtration
2. customrecrystallized from ethanol