反应详情

To a mixture of 2-(2-tritylaminothiazol-4-yl)-2-(Z)-trityloxyiminoacetic acid (III, R2a =Tr) (873 mg, 1.30 m moles) and dichloromethane (5 ml) was added phosphorus pentachloride (297 mg, 1.43 m moles) at -5° C. The mixture was allowed to stand for 20 min at the same temperature and added dropwise to a solution of diphenylmethyl 7-amino-3-(1-propenyl)-3-cephem-4-carboxylate hydrochloride (XIII, R3 =H: 443 mg, 1 m mole) and N,O-bis(trimethylsilyl)acetamide (0.74 ml, 4.4 m moles) in dichloromethane (5 ml) at -5° C. The reaction mixture was allowed to stand for 20 min. at the same temperature and poured into ice-water. Extraction of the mixture with ethyl acetate and evaporation of the extracts under reduced pressure gave the crude product as an oil, which was chromatographed on a column of silica gel (eluted with chloroform) to give the title compound as an amorphous powder. Yield 510 mg (48%).

1. waitto stand for 20 min. at the same temperature
2. extractionExtraction of the mixture
3. customwith ethyl acetate and evaporation of the extracts under reduced pressure
4. customgave the crude product as an oil, which
5. customwas chromatographed on a column of silica gel (eluted with chloroform)