Reacción #93029

Ecuación de reacción

2-methoxyimino-2-(2-formamidothiazol-4-yl)acetic acid

Vilsmeier reagent

benzhydryl 7-amino-3-(2,2-dichlorovinyl)-3-cephem-4-carboxylate hydrochloride

phosphorus oxychloride

→

benzhydryl 7-[2-methoxyimino-2-(2-formamidothiazol-4-yl)acetamido]-3-(2,2-dichlorovinyl)-3-cephem-4-carboxylate

Rendimiento 67.5%

Disolventes

ethyl acetate

water

ethyl acetate

tetrahydrofuran

N,N-dimethylformamide

Condiciones de reacción

Tratamiento posterior

1. 1
   Temperaturacooling
2. 2
   Otroobtained above at -20° C. and mixture
3. 3
   workup.STIRRINGwas stirred at -20° to -10° C. for 30 minutes
4. 4
   Lavadothe separated organic layer was washed in turn with saturated aqueous sodium bicarbonate and brine
5. 5
   Secadodried over magnesium sulfate
6. 6
   OtroThe solution was evaporated in vacuo

Procedimiento

To a stirred suspension of Vilsmeier reagent prepared from N,N-dimethylformamide (0.56 ml) and phosphorus oxychloride (0.664 ml) in tetrahydrofuran (11 ml) in a usual manner was added 2-methoxyimino-2-(2-formamidothiazol-4-yl)acetic acid (syn isomer) (1.38 g) under ice-cooling and the mixture was stirred for 30 minutes at the same temperature. To a solution of benzhydryl 7-amino-3-(2,2-dichlorovinyl)-3-cephem-4-carboxylate hydrochloride (2.5 g) and monotrimethylsilylacetamide (3.95 g) in ethyl acetate (25 ml) was added the activated acid solution obtained above at -20° C. and mixture was stirred at -20° to -10° C. for 30 minutes. After water and ethyl acetate were added to the resultant mixture, the separated organic layer was washed in turn with saturated aqueous sodium bicarbonate and brine, dried over magnesium sulfate. The solution was evaporated in vacuo to give benzhydryl 7-[2-methoxyimino-2-(2-formamidothiazol-4-yl)acetamido]-3-(2,2-dichlorovinyl)-3-cephem-4-carboxylate (syn isomer) (2.28 g).

Fuente