Pyridine → 7-Phenoxyacetamido-3-methyl-3-cephem-4-carboxylic acid

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Reaction Steps

A solution of 7-(2-phenoxyacetamido)-3-methyl-3-bromocepham-4-carboxylic acid (860 mg.) in dry dichloroethane (20 cc) was cooled at -40°--50° C. and pyridine and a 10% dichloromethane solution (4.7 g.) of thionyl chloride were respectively added thereto. The mixture was stirred at -40°--50° C. for one hour and then at room temperature overnight, an poured into ice water and stirred for 30 minutes. The dichloroethane layer was extracted with an aqueous sodium bicarbonate solution and the aqueous layer was acidified with phosphoric acid and extracted with ethyl acetate. The ethyl acetate layer was washed with water, dried, treated with carbon powder and then concentrated to yield crystals (80 mg.) of 7-(2-phenoxyacetamido)-3-methyl-3-cephem-4-carboxylic acid, m.p. 172°-175° C.

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