Abstract: The present invention relates to new cephalosporins of the formula ##STR1## wherein R.sup.1 and R.sup.2 are hydrogen or carboxy, with the proviso that both cannot be the same;R.sup.3 is hydrogen or acetyl; andR.sup.4 is a radical selected from the group consisting of ##STR2## in which n is 1 or 2, R.sup.5 is hydrogen or acetyl, and R.sup.6 is hydrogen, a lower C.sub.1-3 alkyl, or a radical selected from the group consisting of ##STR3## in which n and R.sup.5 are as defined above. In another aspect, this invention relates to processes for the preparation of the compounds of Formula I, to pharmaceutical compositions containing at least one compound of Formula I, and to intermediates in their preparation.

Abstract: The present invention relates to new cephalosporins of the Formula ##STR1## wherein Y is N or CH;R.sup.1 is hydrogen, a straight, branched, or cyclic lower alkyl group having up to six carbon atoms or a radical of the formula ##STR2## in which R.sup.3 and R.sup.4 are each independently hydrogen, methyl, or ethyl, or R.sup.3 and R.sup.4 taken together with the carbon atom to which they are attached, may be a cycloalkylidene ring containing from 3 to 5 carbon atoms;R.sup.2 is a radical selected from the group consisting of ##STR3## in which R.sup.5 is hydrogen or acetyl. In another aspect, this invention relates to processes for the preparation of the compounds of Formula I, to pharmaceutical compositions containing at least one compound of Formula I, and to intermediates in their preparation.

Abstract: This invention relates to novel cephalosporin derivatives of the formula ##STR1## wherein R.sup.1 is hydrogen, a straight, branched, or cyclic lower alkyl group having up to six carbon atoms or a radical of the formula ##STR2## in which R.sup.3 and R.sup.4 are each independently hydrogen, methyl or ethyl, or R.sup.3 and R.sup.4, taken together with the carbon atom to which they are attached, may be a cycloalkylidene ring containing from 3 to 5 carbon atoms;R.sup.2 is a radical selected from the group consisting of ##STR3## wherein R.sup.5 is hydrogen or acetyl; R.sup.6, R.sup.7 and R.sup.8 each are independently C.sub.1-5 alkyl; n is 1 or 2; and y is 1 to 5.In another aspect, this invention relates to compounds of formula I and their nontoxic pharmaeutically acceptable salts, physiologically hydrolyzable esters or solvates.Representative compounds of this invention were selected for testing and were shown to display potent antibacterial activity.

Abstract: The present invention relates to new cephalosporins of the formula ##STR1## wherein R.sup.1 and R.sup.2 are hydrogen or carboxy, with the proviso that both cannot be the same;R.sup.3 is hydrogen or acetyl; andR.sup.4 is a radical selected from the group consisting of ##STR2## in which n is 1 or 2, R.sup.5 is hydrogen or acetyl, and R.sup.6 is hydrogen, a lower C.sub.1-3 alkyl, or a radical selected from the group consisting of ##STR3## in which n and R.sup.5 are as defined above. In another aspect, this invention relates to processes for the preparation of the compounds of Formula I, to pharmaceutical compositions containing at least one compound of Formula I, and to intermediates in their preparation.

Abstract: Compounds of the formula ##STR1## wherein R.sup.1 is hydrogen or a conventional amino-protecting group, R.sup.2 is one of various alkyl, alkenyl, alkynyl, cycloalkyl, carboxyalkyl or carboxycycloalkyl moieties described herein, and R.sup.5 is hydrogen, amino, carboxy, formyl, carbamoyl, guanidino, amidino or one of various alkyl, alkoxy, alkylthio or substituted amino moieties described herein, and nontoxic pharmaceutically acceptable acid addition salts, physiologically hydrolyzable esters and solvates thereof, as well as processes for their preparation, are disclosed. The compounds in which R.sup.1 is hydrogen are potent antibacterial agents.