反应详情

To a mixture of methanol (13 ml) and tetrahydrofuran (13 ml) was dissolved 2-methyl-7-[2-isopropoxyimino-2-(2-formylaminothiazol-4-yl)acetamido]-3-cephem-4-carboxylic acid (syn isomer), which can be represented as 2-methyl-7-[2-isopropoxyimino-2-(2-formylimino-2,3-dihydrothiazol-4-yl)acetamido]-3-cephem-4-carboxylic acid (syn isomer), (1.7 g) and thereto was added concentrated hydrochloric acid (1.5 ml) with stirring at room temperature and then stirring was continued for 2 hours at room temperature. The reaction mixture was concentrated to dryness and the solid was dissolved in water (100 ml) by adding sodium bicarbonate, whereby the resulting mixture was adjusted to pH 7.0. The solution was adjusted to pH 3.0 with concentrated hydrochloric acid under ice-cooling. Precipitates were collected by filtration, washed with water and then dried to give 2-methyl-7-[2-isopropoxyimino-2-(2-aminothiazol-4-yl)acetamido]-3-cephem-4-carboxylic acid (syn isomer), which can be represented as 2-methyl-7-[2-isopropoxyimino-2-(2-imino-2,3-dihydrothiazol-4-yl)acetamido]-3-cephem-4-carboxylic acid (syn isomer), (1.2 g).

1. stirringstirring
2. concentrationThe reaction mixture was concentrated to dryness
3. dissolutionthe solid was dissolved in water (100 ml)
4. additionby adding sodium bicarbonate, whereby the resulting mixture
5. temperaturecooling
6. customPrecipitates
7. filtrationwere collected by filtration
8. washwashed with water
9. customdried