Cephalosporins

A compound selected from the group consisting of syn isomer of a compound of the formula ##STR141## in the R or S form or in the form of an R, S mixture wherein R.sub.l is selected from the group consisting of ##STR142## in the quaternary ammonium form, R and R.sup.1 are individually selected from the group consisting of hydrogen, alkyl of 1 to 4 carbon atoms, alkoxy of 1 to 4 carbon atoms, halogen, CO.sub.2 --Q, ##STR143## CH.sub.2 SQ, Q and Q.sup.1 are individually hydrogen or alkyl of 1 to 4 carbon atoms, R.sub.b and R.sub.c are individually hydrogen or acyl, A and A' are individually selected from the group consisting of hydrogen, an equivalent of an alkali metal, an alkaline earth metal, magnesium, ammonium and amino organic base or A and A' are the remainder of an easily clearable ester group or CO.sub.2 A is CO.sub.2 --;

• and the wavy line indicates that CH.sub.2 R.sub.1 is in the E or Z position and their non-toxic, pharmaceutically acceptable acid addition salts.