@ 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.
3- (活化酯)甲基-3-头孢-4-
羧酸是通过 3-羟甲基-3-头孢-4-
羧酸与活化的 0-酯甲基酰化剂在 4-(叔
氨基)
吡啶催化剂和吸酸碱存在下,在非极性液体溶剂中,于 -78 至 30 摄氏度下直接反应制备的。