反应详情

Ethyl 2-{4-[N-methyl-N-(5-chloro-2-benzoxazolyl)amino]phenoxy}propionate (10.0 g; see Example 7) was suspended in isopropyl alcohol (50 ml) and a solution of sodium hydroxide (1.12 g) in water (50 ml) was added over a period of 45 minutes. Further isopropyl alcohol (60 ml) was added and the mixture was stirred at room temperature for a period of 48 hours. The alcohol was removed by distillation under reduced pressure, the residue was dissolved in water and the aqueous solution was acidified to pH 4 by the addition of aqueous 2 M hydrochloric acid. The precipitate was collected by filtration, dried and recrystallised from ethyl acetate to give the title compound (5.83 g; 63%), mp 152°-154° C. The pmr spectrum of the compound was consistent with the assigned structure.

1. customThe alcohol was removed by distillation under reduced pressure
2. dissolutionthe residue was dissolved in water
3. additionthe aqueous solution was acidified to pH 4 by the addition of aqueous 2 M hydrochloric acid
4. filtrationThe precipitate was collected by filtration
5. customdried
6. customrecrystallised from ethyl acetate