7β-[2-Etherified oximino-2-(thienyl-, furyl- or pyridylacetamido)] cephalosporins

Claim 1

A compound selected from the group consisting of a highly active cephalosporin antibiotic highly stable to β-lactamases, having the formula: ##STR146## wherein R u is thienyl, furyl, or pyridyl or any of these groups substituted by a chloro, bromo, iodo, fluoro, hydroxy, lower alkyl, nitro, amino, lower alkylamino, diloweralkylamino, lower alkanoyl, lower alkanoylamino, lower alkoxy, lower alkylthio or carbamoyl group; R b is phenyl, napththyl, benzyl, phenylethyl, diphenylmethyl, triphenylmethyl, thienylmethyl, furylmethyl, pyridylmethyl, pyrrolylmethyl or any of these groups substituted by a hydroxy, lower alkoxy, phenoxy, benzyloxy, carboxy, lower alkoxycarbonyl, benzyloxycarbonyl, mercapto, lower alkylthio, phenylthio, benzylthio, acetamido, benzamido, cyano, formyl, lower alkanoyl, benzoyl, amino, methylamino, ethylamino, dimethylamino, lower alkoxycarbonylamino, benzyloxycarbonylamino, phthalimido, acetoxy, propionyloxy, pivaloyloxy, chloro, bromo, iodo, fluoro, nitro, or azido group, and Y is a group of formula -SW and W is thiadiazolyl, 5-methyl-1,3,4-thiadiazol-2-yl, diazolyl, triazolyl, tetrazolyl, 1-methyltetrazol-5-yl, 1-ethyltetrazol-5-yl, thiatriazolyl, oxazolyl, oxadiazolyl, 2-phenyl-1,3,4-oxadiazol-5-yl, benzimidazolyl, benzoxazolyl, triazolopyridyl, benzothiazolyl, nitrobenzothiazolyl, purinyl, pyridyl, pyrimidyl or an alkyl group of 1-4 carbon atoms; said cephalosporin antibiotic being in the form of a syn isomer free of the corresponding anti-isomer to the extent of at least 75% based on the total weight of said antibiotic; and a physiologically acceptable salt thereof.