反应详情

Conc. hydrochloric acid (0.7 ml.) was added to a solution of 7-[2-(2-formamido-5-bromothiazol-4-yl)-2-methoxyiminoacetamido]-2-methoxy-3-cephem-4-carboxylic acid (syn isomer, 1.4 g.) in methanol (45 ml.) and stirred at room temperature for 2 hrs. and further for 3.5 hrs. under ice-cooling. The reaction mixture was treated with activated charcoal. Water (30 ml.) was added to the solution and adjusted to pH 6.5 with 1N-aqueous sodium hydroxide, and methanol was distilled off. Ethyl acetate was added to the residue and adjusted to pH 2.5 with 1N-hydrochloric acid. The ethyl acetate layer was separated and the aqueous layer was washed with ethyl acetate. The ethyl acetate solution obtained above and the washings were combined, dried over magnesium sulfate, treated with activated charcoal and evaporated in vacuo. The residue was pulverized with diethyl ether, and the precipitates were collected by filtration and dried to give 7-[2-(2-amino-5-bromothiazol-4-yl)-2-methoxyiminoacetamido]-2-methoxy-3 -cephem-4-carboxylic acid (syn isomer, 1.2 g.).

1. waitand further for 3.5 hrs
2. temperatureunder ice-cooling
3. distillationwas distilled off
4. additionEthyl acetate was added to the residue
5. customThe ethyl acetate layer was separated
6. washthe aqueous layer was washed with ethyl acetate
7. customThe ethyl acetate solution obtained above and the washings
8. dry with materialdried over magnesium sulfate
9. additiontreated with activated charcoal
10. customevaporated in vacuo
11. filtrationthe precipitates were collected by filtration
12. customdried