反应详情

A mixture of hydroxylamine sulfate (344.0 g), water (904 ml) and a 25% aqueous sodium hydroxide solution (456 ml) is stirred, and thereto are added 4-hydroxycoumarin (168.0 g) and ethylenediaminetetraacetic acid disodium salt dihydrate (3.2 g), and the mixture is stirred with heating at 84° C.-86° C. for 4 hours. The reaction mixture is cooled, and thereto is added 1,2-dichloroethane (240 ml). The mixture is stirred, and the aqueous layer is collected. The pH value of the aqueous layer is adjusted to pH 1-2 with 25% sulfuric acid, and the precipitated crystals are collected by filtration, washed with water, and dried with air at 60° C. for 15 hours to give 1,2-benzisoxazole-3-acetic acid (170.4 g).

1. temperaturewith heating at 84° C.-86° C. for 4 hours
2. temperatureThe reaction mixture is cooled
3. stirringThe mixture is stirred
4. customthe aqueous layer is collected
5. filtrationthe precipitated crystals are collected by filtration
6. washwashed with water
7. customdried with air at 60° C. for 15 hours