反应详情

Pyridine (3 g.) was added to a solution of ethyl 2-methoxyimino-2-(2-amino-1,3-thiazol-4-yl)acetate (syn isomer) (6.5 g.) in a mixture of ethyl acetate (60 ml.) and dimethylformamide (20 ml.). To the solution was dropwise added with stirring at 4° C. ethyl chloroformate (8 g.). After adding water (50 ml.) to the reaction mixture, the organic layer was separated, washed with water and then with a saturated aqueous solution of sodium chloride and dried over magnesium sulfate. The solvent was distilled off under reduced pressure. The residue was subjected to column chromatography on silica gel (120 g.) using a mixture of ether and petroleum ether (5:2) as an eluent to give ethyl 2-methoxyimino-2-(2-ethoxycarbonylamino-1,3-thiazol-4-yl)acetate (syn isomer) (5.4 g.).

1. additionTo the solution was dropwise added
2. customthe organic layer was separated
3. washwashed with water
4. dry with materialwith a saturated aqueous solution of sodium chloride and dried over magnesium sulfate
5. distillationThe solvent was distilled off under reduced pressure
6. additiona mixture of ether and petroleum ether (5:2) as an eluent