1-dethia-2-thia-cephalosporanic acids

A compound selected from the group consisting of 1-dethia-2-thia-cephalosporanic acids of the formula ##STR37## wherein R' is selected from the group consisting of hydrogen, alkyl of 1 to 6 carbon atoms, alkenyl and alkynyl of 2 to 6 carbon atoms, and cycloalkyl of 3 to 6 carbon atoms substituted or unsubstituted with at least one member of the group consisting of halogen, carboxy, salified carboxy, esterified carboxy, alkoxy, oxo, alkylthio, mercapto, hydroxy, amino, nitro, carbamoyl and cyano, n.sub.2 is 0, 1 or 2, R.sub.4 is hydrogen or methoxy, R.sub.1B is --(CH.dbd.CH).sub.n1 --CH.sub.2 --S--R.sub.m, n.sub.1 is 0, 1 or 2, R.sub.m is an unsaturated group including a positively charged and double bonded nitrogen atom, the said group being bonded to the sulfur atom through a carbon atom and selected from the group consisting of pyridyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, pyrazolyl, triazolyl, tetrazolyl, pyridazinyl, pyrimidinyl, pyrazinyl, quinoleinyl, isoquinoleinyl, cinnolinyl, quanazolinyl, pyridino pyrimidinyl, dihydro- or tetrahydro-pyridyl, unsubstituted or substituted by at least one member selected from the group of alkyl of 1 to 4 carbon atoms, methoxy, ethoxy, halogen, carboxyalkyl, esterified carboxyalkyl, carbamoyl, thioacetylalkyl, thiocarbamoylalkyl, haloalkyl, cyanoalkyl and alkenyl of 2 to 4 carbon atoms Y is methine or nitrogen and A is selected from the group consisting of hydrogen, alkali metal ion, or alkaline earth metal ion, magnesium ion, ammonium ion, an organic amine base and an ester group or --COOA is --COO.sup.- and their non-toxic, pharmaceutically acceptable acid addition salts.