反应详情

温度

40 °C

A mixture of ethyl 2-(2-bromoethoxyimino)-4-chloro-3-oxobutyrate (syn isomer, 156 g.), thiourea (39.4 g.) sodium acetate trihydrate (70.5 g.), water (300 ml.) and ethanol (500 ml.) was stirred at 40° C. for an hour. The resultant solution was concentrated in vacuo and the residue was extracted twice with ethyl acetate. The extracts were washed with a saturated aqueous solution of sodium chloride, dried over magnesium sulfate and concentrated in vacuo. After adding diethyl ether (1 l.) to the oily residue, the soluble substance was separated by decantation and the solution was concentrated in vacuo. The residue was crystallized with diisopropyl ether and the precipitates were collected by filtration to give ethyl 2-(2-aminothiazol-4-yl)-2-(2-bromoethoxyimino)acetate (syn isomer, 46.4 g.), mp. 111° to 114° C.

1. concentrationThe resultant solution was concentrated in vacuo
2. extractionthe residue was extracted twice with ethyl acetate
3. washThe extracts were washed with a saturated aqueous solution of sodium chloride
4. dry with materialdried over magnesium sulfate
5. concentrationconcentrated in vacuo
6. additionAfter adding diethyl ether (1 l.) to the oily residue
7. customthe soluble substance was separated by decantation
8. concentrationthe solution was concentrated in vacuo
9. customThe residue was crystallized with diisopropyl ether
10. filtrationthe precipitates were collected by filtration