反应详情

The product from step (B) (7.9 g) was suspended in methanol (90 ml) and stirred with 1 N sodium hydroxide solution (90 ml) for 2.5 hours. The resulting dark solution was evaporated to half volume and then diluted with water (160 ml) and acidified with concentrated hydrochloric acid, with cooling in an ice bath. The precipitated product was collected by filtration, washed with water (200 ml), sucked dry and recrystallised from aqueous dimethylformamide. The title compound was isolated as yellow crystals after drying in vacuo at 60° C. m.p. 240°-242° C. (sinters at ~225° C.)

1. customThe resulting dark solution was evaporated to half volume
2. additiondiluted with water (160 ml)
3. temperaturewith cooling in an ice bath
4. filtrationThe precipitated product was collected by filtration
5. washwashed with water (200 ml)
6. customsucked dry
7. customrecrystallised from aqueous dimethylformamide