反应详情

An amount of 237.5 gm (1.146 mol) of 6-methoxy-4,4-dimethyl-4H-3,1-benzoxazin-2-one is dissolved in 2.4 liters of dry ethylene chloride, and 125 ml (330.3 gm=1.3 mol) of boron tribromide are added thereto dropwise, under stirring, at -30° to -40° C. After the addition is complete, the mixture is allowed to return to ambient temperature and left overnight. Then, 1 liter of 50% ethanol is added dropwise, under cooling and stirring, and the mixture is evaporated down to about 500 ml and then diluted with 3 liters of water. The precipitate is subjected to suction filtration and dried.

1. additionAfter the addition
2. customto return to ambient temperature
3. temperatureunder cooling
4. stirringstirring
5. customthe mixture is evaporated down to about 500 ml
6. additiondiluted with 3 liters of water
7. filtrationThe precipitate is subjected to suction filtration
8. customdried