Bristol-Myers Company

Albert L Vulcano

Chester Sapino, Jr

David A Johnson

Steven P Brundidge

Joseph H Grossman

James Mahan

7-Aminocephalosporanic acid (7-ACA) and 7-amino-3-methyl-3-cephem-4-carboxylic acid (7-ADCA) are valuable intermediates in the preparation of semi-synthetic cephalosporins. These compounds are commonly prepared by cleaving the amide bond of compounds having the formula ##SPC1## In which R.sup.6 is H or ##EQU1## R is the side chain of a known penicillin, especially phenoxymethyl or benzyl, and the amino and carboxyl functions are blocked; by A. halogenating the blocked compounds Ia or IIa to produce an imino-halide; B. forming an imino-ether from the imino-halide by treatment with an alcohol; and C. mixing said imino-ether with water or an alcohol to produce 7-aminocephalosporanic acid or 7-amino-3-methyl-3-cephem-4-carboxylic acid. The invention claimed is the use of dicyclohexylamine or diisopropylamine instead of a tertiary amine acid scavenger in step A.

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Liverpool, NY, United States of America

Albert L Vulcano