反应详情

A solution of 1-methylimidazole (0.5 g.) in 1 N sodium hydroxide aqueous solution (48 ml.) was added to a solution of ethyl 2-(2-aminothiazol-4-yl)-2-(2,4-dichorobenzyloxyimino)acetate (syn isomer, 12.0 g.), methanol (120 ml.) and tetrahydrofuran (100 ml.) at 15° to 20° C., and stirred at 35° to 40° C. for 6 hours. After removing methanol and tetrahydrofuran in vacuo from the resultant mixture, the aqueous residue was washed with ethyl acetate. Ethyl acetate was completely removed from the aqueous solution and adjusted to pH 2.0 with hydrochloric acid. The precipitates were collected by filtration to give 2-(2-aminothiazol-4-yl)-2-(2,4-dichlorobenzyloxyimino)acetic acid (syn isomer, 10.0 g.).

1. customAfter removing methanol and tetrahydrofuran in vacuo from the resultant mixture
2. washthe aqueous residue was washed with ethyl acetate
3. customEthyl acetate was completely removed from the aqueous solution
4. filtrationThe precipitates were collected by filtration