Reacción #342916

Ecuación de reacción

ethyl 2-(2-bromoethoxyimino)-4-chloro-3-oxobutyrate

thiourea

sodium acetate trihydrate

water

→

ethyl 2-(2-aminothiazol-4-yl)-2-(2-bromoethoxyimino)acetate

Rendimiento 27.8%

Disolventes

ethanol

Condiciones de reacción

Tratamiento posterior

1. 1
   ConcentraciónThe resultant solution was concentrated in vacuo
2. 2
   Extracciónthe resiude was extracted twice with ethyl acetate
3. 3
   LavadoThe extracts were washed with a saturated aqueous solution of sodium chloride
4. 4
   Secadodried over magnesium sulfate
5. 5
   Concentraciónconcentrated in vacuo
6. 6
   workup.ADDITIONAfter adding diethyl ether (1 l.) to the oily residue
7. 7
   Otrothe soluble substance was separated by decantation
8. 8
   Concentraciónthe solution was concentrated in vacuo
9. 9
   OtroThe residue was crystallized with diisopropyl ether
10. 10
    Filtraciónthe precipitates were collected by filtration

Procedimiento

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 resiude 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.

Fuente