7-[2-(2-Imino-4-thiazolin -4-yl)-2-(syn)-hydroxy-iminoacetamido]-cephalosporins

A 2-(syn)-hydroxyimino-acetamide compound of the formula:

• ##STR75## wherein W is sulfur;
• Het is substituted or unsubstituted heterocyclic;
• said heterocyclic is pyridyl, N-oxopyridyl, pyrimidyl, pyridazinyl, N-oxopyridazinyl, pyrazolyl, imidazolyl, thiazolyl, 1,2,3-thiadiazolyl, 1,2,4-thiadiazolyl, 1,3,4-thiadiazolyl, 1,2,5-thiadiazolyl, 1,2,3-oxadiazolyl, 1,2,4-oxadiazolyl, 1,3,4-oxadiazolyl, 1,2,5-oxadiazolyl, 1,2,3-triazolyl, 1,2,4-triazolyl, 1H-tetrazolyl, 2-H-tetrazolyl, or a pharmaceutically acceptable salt or ester thereof;
• when Het is substituted, the substituent is alkyl of one to four carbon atoms, haloalkyl of one to four carbon atoms, alkoxy of one to four carbon atoms, halogen, hydroxyl, mercapto, amino, carboxyl, carbamoyl, a group of the formula:
• --X--Z.sup.1 in which X is an alkylene of one to four carbon atoms and Z.sup.1 is hydroxyl, mercapto, amino, a mono- or di-alkylamino of which the alkyl has one to four carbon atoms, guanyl, carboxyl, sulfo, carbamoyl, an alkoxycarbonyl of which the alkyl has one to four carbon atoms, a mono- or di-alkylcarbamoyl of which alkyl has one to four carbon atoms, an alkoxy of one to four carbon atoms, an alkylthio of which alkyl has one to four carbon atoms, an alkylsulfonyl of which alkyl has one to four carbon atoms or an alkylcarbonyloxy of which alkyl has one to four carbon atoms, a group of the formula:
• --S--Z.sup.2 in which Z.sup.2 is an alkyl of one to four carbon atoms or the group --X--Z.sup.1, or the substituent is a group of the formula:
• ##STR76## in which each of Z.sup.3 and Z.sup.4 is an alkyl of one to four carbon atoms, the group --X--Z.sup.1, an alkoxycarbonyl of which alkoxy has one to four carbon atoms, an alkylcarbonyl of which alkyl has one to four carbon atoms, carbamoyl or a mono- or di-alkylcarbamoyl of which alkyl has one to four carbon atoms.