反应详情

Pyridine (0.55 g.) and phosphorus pentachloride (1.43 g.) were added in turn under cooling at -5° to -10° C. to a suspension of 2,2,2-trichloroethyl 2-methyl-7-(2-phenylacetamido)-3-cephem-4-carboxylate (2.14) in dried dichloromethane (20 ml.), and the mixture was stirred. After dissolution of the starting material, the reaction temperature was elevated to at room temperature, and stirred for 4 hours. To this solution was dropwise added absolute methanol (1.47 g.) under cooling at -10° to -15° C. After stirring for 1 hour at the same temperature and 1.5 hours at 2° to 3° C., the precipitated crystals were collected by filtration, washed with a small amount of dichloromethane and ether, and dried to give colorless crystals of 2,2,2-trichloroethyl 2-methyl-7-amino-3-cephem-4-carboxylate hydrochloride (1.26 g.), mp 185° to 187° C. (dec.). Similar results were obtained by using the following compounds as a starting compound instead of 2,2,2-trichloroethyl 2-methyl-7-(2-phenylacetamido)-3-cephem-4-carboxylate.

1. dissolutionAfter dissolution of the starting material
2. customwas elevated to at room temperature
3. stirringstirred for 4 hours
4. temperatureunder cooling at -10° to -15° C
5. stirringAfter stirring for 1 hour at the same temperature and 1.5 hours at 2° to 3° C.
6. filtrationthe precipitated crystals were collected by filtration
7. washwashed with a small amount of dichloromethane and ether
8. customdried