反应详情

Ethanol (10 ml.) was added to a suspension of ethyl 2-methoxyimino-2-(2-aminothiazol-4-yl)acetate (syn isomer), which can be represented as ethyl 2-methoxyimino-2-(2-imino-2,3-dihydrothiazol-4yl)acetate (syn isomer), (2.2 g.) in a 1N aqueous solution of sodium hydroxide (12 ml.) and the mixture was stirred for 15 hours at ambient temperature. The reaction mixture was adjusted to pH 7.0 with 10% hydrochloric acid and ethanol was distilled off under reduced pressure. The residual aqueous solution was washed with ethyl acetate, adjusted to pH 2.8 with 10% hydrochloric acid and stirred under ice-cooling to precipitate crystals. The crystals were collected by filtration, washed with acetone and recrystallized from ethanol to give colorless needles of 2-methoxyimino-2-(2-aminothiazol-4-yl)acetic acid (syn isomer), which can be represented as 2-methoxyimino-2-(2-imino-2,3-dihydrothiazol-4-yl)acetic acid (syn isomer), (1.1 g.).

1. distillationwas distilled off under reduced pressure
2. washThe residual aqueous solution was washed with ethyl acetate
3. stirringstirred under ice-
4. temperaturecooling
5. customto precipitate crystals
6. filtrationThe crystals were collected by filtration
7. washwashed with acetone
8. customrecrystallized from ethanol