ES414153A1 - Process for prepating a cephalosporin - Google Patents

Abstract

In a procedure for cleavage of the 7-carboxamido group of a cephalosporin of the formula. **(See formula)** where R is aminoadipoyl; an amino adipoyl group in which the amino group is protected with C1 to C8 alkanoyl, C6 to C12 aroyl, C1 to C4 alkyloxycarbonyl, C6 to C12 aryloxycarbonyl or one of these protecting groups substituted by halogen, nitro or C1 to C3 alkyloxy; or R is C2 to C8 alkanoyl, α-monohaloalkanoyl C2 to C8, α-dihaloalkanoyl C2 to C8, **(See formula)** where Y is oxygen, sulfur a carbon-carbon bond; n is an integer from 0 to 3 and is at least 1 when Y is oxygen or sulfur; m is an integer from 1 to 3; Q is amino, hydroxy, or carboxy; or R is otherwise the acyl group derived from a penicillin used to prepare cephalosporin; X is C2-C6 alkanoyloxy, C2-C6 thyalkanoyloxy, C6-C12 thioaroyloxy hydroxy, mercapto, hydrogen, C1-C3 alkoxythionocarboxylthio, C1-C6 alkoxy or C1-C6 alkylthio; and R1 is hydrogen, an alkali metal or a carboxyl esterifying group selected from 2,2,2-trichlorethyl, p-nitrobenzyl, phenacyl, benzohydrile, tert-butyl and p-methoxybenzyl and where any amino, carboxyl, hydroxy and mercapto groups of the molecule is blocked with a blocking reagent, by treating it blocked cephalosporin with a halogenating agent to convert the 7-carboxamide group of cephalosporin to an iminohalide, treating the iminohalide with an alcohol to form an iminoether and hydrolyzing the iminoether to form a group 7 -amino, the improvement characterized by carrying out the protection reaction of the carboxyl group and the cleavage reactions of the carboxyamide in an organic diluent selected from tetrahydrofuran, bis (2-methoxyethyl ether), 2-methoxyethyl acetate, ethylene glycol diacetate, 1, 4-dioxane, 1,3-dioxane, and organic liquid mixtures thereof with water miscible. (Machine-translation by Google Translate, not legally binding)