NOVEL CEPHALOSPORIN COMPOUND

Compounds of the formula wherein A is phenyl, 4-hydroxy-phenyl, 2-thienyl, 3-thienyl or 3,4-dihydroxy-phenyl; Het is 4H-5,6-dioxo-1,2,4-triazin-3-yl, 4-methyl-5,6-dioxo-1,2,4-triazin-3-yl, 1-vinyl-tetrazol-5-yl, 1-allyl-tetrazol-5-yl or where n is an integer from 1 to 3, inclusive, R1 is hydroxyl, amino, dimethylamino, acetylamino, aminocarbonyl, aminocarbonylamino, aminosulfonyl, aminosulfonylamino, methylcarbonyl, methylsulfonylamino, cyano, hydroxysulfonylamino, methylsulfonyl, methylsulfinyl, a carboxylic acid group or a sulfonic acid group, or -(CH2)n-R1 may also be alkyl of 2 to 4 carbon atoms or 2,3-dihydroxy-propyl; R2 is an unsubstituted or monosubstituted heterocyclic radical selected from the group consisting of 3-pyridyl, 5-pyrimidinyl, 2-thienyl, 2-furylmethyl, 2-thienylmethyl, 2-imidazolylmethyl, 2-thiazolylmethyl, 3-pyridylmethyl or 5-pyrimidinylmethyl, where the substituent is chlorine, methyl, acetylamino, hydroxyl, methylsulfinyl, methylsulfonyl, aminocarbonyl or aminosulfonyl; and E is hydrogen or a protective group which is easily removable in vitro or in vivo; and, when E is hydrogen, non-toxic, pharmacologically acceptable salts thereof formed with inorganic or organic bases; the compounds as well as their salts are useful as antibiotics.