反应详情

Dichloroacetyl chloride (3.58 g.) was added with stirring and ice-cooling to a suspension of 2-hydroxyimino-2-(isothiazol-4-yl)acetic acid (syn isomer) (1.50 g.) in dry methylene chloride (40 ml.), and the mixture was stirred for 2 hours at the same temperature. The reaction mixture was concentrated to the volume of 10 ml. Petroleum ether (50 ml.) was added to the residue and the mixture was cooled in dry ice-acetone bath. Precipitates were collected by filtration and washed with petroleum ether to give 2-dichloroacetoxyimino-2-(isothiazol-4-yl)acetic acid (syn isomer) (1.20 g.).

1. stirringthe mixture was stirred for 2 hours at the same temperature
2. concentrationThe reaction mixture was concentrated to the volume of 10 ml
3. additionPetroleum ether (50 ml.) was added to the residue
4. temperaturethe mixture was cooled in dry ice-acetone bath
5. customPrecipitates
6. filtrationwere collected by filtration
7. washwashed with petroleum ether