Reacción #62542

Ecuación de reacción

1-Bromoethylethyl carbonate

sodium 7-[(Z)-2-methoxyimino-2-(thiazol-4-yl)acetamido]-3-(3-methyl-1,2,4-thiadiazol-5-yl)thiomethyl-3-cephem-4-carboxylate

ethyl acetate

water

→

title compound

1-Ethoxycarbonyloxyethyl 7-[(Z)-2-methoxyimino-2-(thiazol-4-yl)acetamido]-3-(3-methyl-1,2,4-thiadiazol-5-yl)thiomethyl-3-cephem-4-carboxylate

Disolventes

dimethylformamide

Condiciones de reacción

Tratamiento posterior

1. 1
   Temperaturaunder cooling with ice
2. 2
   workup.STIRRINGwith stirring
3. 3
   OtroThe ethyl acetate layer was separated
4. 4
   Lavadowashed successively with water (20 ml, adjusted to pH 3 with dil. HCl), 10% aqueous K2HPO4 solution (20 ml) twice
5. 5
   Concentraciónconcentrated in vacuo
6. 6
   workup.ADDITIONthe residue was added dropwise to petroleum ether
7. 7
   FiltraciónThe formed crystals were filtered
8. 8
   Otrodried in vacuo

Procedimiento

1-Bromoethylethyl carbonate (472 mg) was added to a solution of sodium 7-[(Z)-2-methoxyimino-2-(thiazol-4-yl)acetamido]-3-(3-methyl-1,2,4-thiadiazol-5-yl)thiomethyl-3-cephem-4-carboxylate (536 mg) in dimethylformamide (5 ml) under cooling with ice. The mixture was stirred for 3 hr and then poured into a mixture of ethyl acetate (120 ml) and water (20 ml, adjusted to pH3 with dil. HCl) with stirring. The ethyl acetate layer was separated, washed successively with water (20 ml, adjusted to pH 3 with dil. HCl), 10% aqueous K2HPO4 solution (20 ml) twice, and saturated saline water (20 ml), drived over MgSO4, concentrated in vacuo, and the residue was added dropwise to petroleum ether. The formed crystals were filtered and dried in vacuo to give the title compound (325 mg). This product was found to contain the Δ2 isomer.

Fuente