abstract |
@ 3-(Activated ester)methyl-3-cephem 4-carboxylic acids are prepared by the direct reaction of a 3-hydroxymethyl-3-cephem-4-carboxylic acid with an activated-0-ester-methyl forming acylating agent, in the presence of a 4-(tertiary amino) pyridine catalyst and an acid-absorbing base, in a non-polar liquid solvent, at -78 to 30 C. Certain products of the reaction are novel. |