反应详情

A solution of 7.3 g of 80% strength sodium chlorite in 15 ml of water is added dropwise with continuous stirring to a mixture of 10.0 g of 4-difluoromethoxy-3-methoxybenzaldehyde, 6.5 g of sulphamic acid and 50 ml of glacial acetic acid. The internal temperature is kept between 30° and 35° C. by cooling with ice water. After dropwise addition is complete, the mixture is stirred for a further 1 h and then diluted with water. The precipitated 4-difluoromethoxy-3-methoxybenzoic acid is filtered off with suction, washed with water, dried in vacuo and crystallized from acetonitrile/petroleum ether (b.p. 40°) 2/8. Yield 7.1 g; m.p. 170° C.

1. customis kept between 30° and 35° C.
2. additionAfter dropwise addition
3. filtrationThe precipitated 4-difluoromethoxy-3-methoxybenzoic acid is filtered off with suction
4. washwashed with water
5. customdried in vacuo
6. customcrystallized from acetonitrile/petroleum ether (b.p. 40°) 2/8