Abstract: [(Thioalkyl)thioacetyl]cephalosporin derivatives of the formula ##STR1## wherein R is hydrogen, lower alkyl, phenyl-lower alkyl, tri(lower alkyl)silyl, a salt forming ion, or the group ##STR2## R.sub.1 is hydrogen, lower alkyl, phenyl, thienyl or furyl; R.sub.2 and R.sub.6 each is hydrogen or lower alkyl; R.sub.3 and R.sub.5 each is lower alkyl, phenyl or phenyl-lower alkyl and R.sub.4 is hydrogen, hydroxy or lower alkanoyloxy; are useful as antimicrobial agents.

Abstract: 7.beta.-[[[2-Acylamino]-1,2-dioxoethyl]amino]acyl cephalosporins of the formula ##STR1## wherein R is hydrogen, lower alkyl, phenyl-lower alkyl, diphenyl-lower alkyl, tri(lower alkyl)silyl, trihaloethyl or a salt forming ion; R.sub.1 is hydrogen, lower alkyl, saturated or unsaturated cycloalkyl, phenyl, phenyl-lower alkyl, substituted phenyl or certain heterocyclic groups; R.sub.2 is hydrogen or methoxy; R.sub.3 is hydrogen, lower alkyl or phenyl-lower alkyl; R.sub.4 is lower alkyl, cycloalkyl, phenyl, substituted phenyl or certain heterocyclic groups; and X is hydrogen, lower alkanoyloxy, carbamoyloxy, lower alkoxy, lower alkylthio, ##STR2## or certain heterothio groups, are useful as antibacterial agents.

Abstract: 6-[[[(2-Cyanomethyl)amino]-1,2-dioxoethyl]amino]acyl pencillins which have the formula ##STR1## wherein R is hydrogen, lower alkyl, tri(lower alkyl)silyl, tri(lower alkyl)stannyl, trihaloethyl or a salt forming ion; R.sub.1 is hydrogen, lower alkyl, saturated or unsaturated cycloalkyl, phenyl, phenyl-lower alkyl, substituted phenyl or certain heterocyclic groups; R.sub.2 is hydrogen or methoxy; R.sub.3 is hydrogen, lower alkyl, phenyl-lower alkyl or cycloalkyl; and R.sub.4 and R.sub.5 each is hydrogen or lower alkyl, are useful as antibacterial agents.

Abstract: Carbamoylalkylureido cephalosporins of the formula ##STR1## wherein R is hydrogen, lower alkyl, phenyl-lower alkyl, diphenyl-lower alkyl, tri(lower alkyl)silyl, trihaloethyl, a salt forming ion, or the group ##STR2## R.sub.1 is hydrogen or methoxy; A is straight or branched chain alkylene of 1 to 6 carbons; R.sub.2 and R.sub.3 are independently selected from hydrogen and straight chain alkyl of 1 to 4 carbons, or R.sub.2 is hydrogen and R.sub.3 is branched chain alkyl of 3 or 4 carbons, phenyl, benzyl or phenethyl, or R.sub.2 and R.sub.3 taken together with N atom to which they are attached form ##STR3## R.sub.4 is hydrogen or lower alkyl; R.sub.5 is hydrogen, lower alkyl, cycloalkyl, cycloalkenyl, cycloalkadienyl, phenyl, phenyl-lower alkyl, substituted phenyl, substituted phenyl-lower alkyl, or certain heterocyclic groups; R.sub.6 is hydrogen or lower alkyl; R.sub.7 is lower alkyl; and X is hydrogen, lower alkanoyloxy, ##STR4## or certain heterothio groups; are disclosed.

Abstract: Cyanoalkylureido cephalosporins of the formula ##STR1## wherein R is hydrogen, lower alkyl, phenyl-lower alkyl, diphenyl-lower alkyl, tri(lower alkyl)silyl, trihaloethyl, a salt forming ion, or the group ##STR2## R.sub.1 is hydrogen or methoxy; A is straight or branched chain alkylene or ##STR3## R.sub.2 is phenyl, 2-thienyl, or 3-thienyl; R.sub.3 is hydrogen or lower alkyl; R.sub.4 is hydrogen, lower alkyl, cycloalkyl, cycloalkenyl, cycloalkadienyl, phenyl, phenyl-lower alkyl, substituted phenyl, substituted phenyl-lower alkyl, or certain heterocyclic groups; R.sub.5 is hydrogen or lower alkyl; R.sub.6 is lower alkyl; and X is hydrogen, lower alkanoyloxy, ##STR4## or certain heterothio groups; are disclosed. These compounds are useful as antibacterial agents.

Abstract: New .alpha.-hydrazinocarbonylamino cephalosporins which have the formula ##STR1## are useful as antimicrobial agents.

Abstract: L-Isomer compounds of the formula ##STR1## wherein R.sub.1 is phenyl, thienyl or furyl; R.sub.4 represents certain heterocyclic groups; R.sub.3 is hydrogen, lower alkyl, phenyl-lower alkyl, substituted phenyl-lower alkyl, diphenyl-lower alkyl, tri(lower alkyl)stannyl, tri(lower alkyl)silyl, a salt forming ion, or the group ##STR2## wherein R is lower alkyl, phenyl, phenyl-lower alkyl, or substituted phenyl and phenyl-lower alkyl are disclosed. These compounds are useful as antibacterial agents.

Abstract: New 1,7-dihydro-1-substituted-3H-pyrazolo[4,3-e]-1,2,4-triazolo[4,3-c]pyrimidi ne-3-thione and 3-one mesoionic didehydro derivatives which have the formula ##STR1## wherein R.sub.1 is hydrogen, lower alkyl, phenyl-lower alkyl, cycloalkyl or hydroxy-lower alkyl;R.sub.2 is hydrogen or lower alkyl;R.sub.3 is lower alkyl, cycloalkyl or hydroxy-lower alkyl; andX is sulfur or oxygen,Are useful as anti-inflammatory agents.

Abstract: 7.beta.-[(2-Amino-1,2-dioxoethyl)amino]acyl cephalosporins of the formula ##STR1## wherein R is hydrogen, lower alkyl, phenyl-lower alkyl, diphenyl-lower alkyl, tri(lower alkyl)silyl, trihaloethyl or a salt forming ion; R.sub.1 is hydrogen, lower alkyl, saturated or unsaturated cycloalkyl, phenyl, phenyl-lower alkyl, substituted phenyl or certain heterocyclic groups; R.sub.2 is hydrogen or methoxy; R.sub.3 is hydrogen, lower alkyl or cycloalkyl; and X is hydrogen, lower alkanoyloxy, carbamoyloxy, lower alkoxy, lower alkylthio ##STR2## or certain heterothio groups, are useful as antibacterial agents.

Abstract: New compounds of the following general formula, and their salts ##STR1## wherein R.sub.1 and R.sub.2 each is hydrogen, lower alkyl, lower alkenyl, phenyl, hydroxyphenyl, chlorophenyl, benzyl, phenethyl, or R.sub.1 and R.sub.2 together complete a cyclopentyl or cyclohexyl group; R.sub.3 is hydrogen, lower alkyl, lower alkenyl, cyclopentyl, cyclohexyl, phenyl, hydroxyphenyl, aminophenyl, chlorophenyl, benzyl, furyl, thienyl, pyrrolidyl or pyridyl; and R.sub.5 is hydrogen or lower alkyl; are intermediates for the production of cephalosporin derivatives.

Abstract: Ureido cephalosporin derivatives of the formula ##STR1## wherein R is hydrogen, lower alkyl, phenyl-lower alkyl, diphenyl-lower alkyl, tri(lower alkyl)silyl, trihaloethyl, a salt forming ion, or the group ##STR2## R.sub.1 is hydrogen, lower alkyl, cycloalkyl, cycloalkenyl, cycloalkadienyl, phenyl, phenyl-lower alkyl, substituted phenyl or phenyl-lower alkyl, or certain heterocyclic groups; R.sub.2 is hydrogen or lower alkyl; R.sub.3 is hydrogen or methoxy; R.sub.4 is hydrogen, halogen, lower alkyl, or lower alkoxy; R.sub.5 is hydrogen or lower alkyl; R.sub.6 is lower alkyl, phenyl, or phenyl-lower alkyl; are disclosed. These compounds are useful as antibacterial agents.

Abstract: Alkenyl and alkinylureido cephalosporins of the formula ##STR1## wherein R is hydrogen, lower alkyl, phenyl-lower alkyl, diphenyl-lower alkyl, tri(lower alkyl)silyl, trihaloethyl, a salt forming ion, or the group ##STR2## R.sub.1 is hydrogen or methoxy; R.sub.2 is lower alkenyl or alkinyl, R.sub.3 is hydrogen or lower alkyl; R.sub.4 is hydrogen, lower alkyl, cycloalkyl, cycloalkenyl, cycloalkadienyl, phenyl, phenyl-lower alkyl, substituted phenyl, substituted phenyl-lower alkyl, or certain heterocyclic groups; R.sub.5 is hydrogen or lower alkyl; R.sub.6 is lower alkyl; and X is hydrogen, lower alkanoyloxy, ##STR3## OR CERTAIN HETEROTHIO GROUPS; ARE DISCLOSED. These compounds are useful as antibacterial agents.

Abstract: Ureido cephalosporin derivatives of the formula ##STR1## wherein R.sub.1 is hydrogen or methoxy; R.sub.2 is hydrogen or lower alkyl; R.sub.3 is hydrogen, lower alkyl, cycloalkyl, cycloalkenyl, cycloalkadienyl, phenyl, phenyl-lower alkyl, substituted phenyl, substituted phenyl-lower alkyl; or certain heterocyclic groups; are disclosed. These compounds are useful as antibacterial agents.

Abstract: [[[Imidazolidinyl amino]carbonyl]amino]acetylcephalosporin derivatives having the formula ##STR1## wherein R is hydrogen, lower alkyl, phenyl-lower alkyl, diphenyl-lower alkyl, tri(lower alkyl)silyl, trihaloethyl, a salt forming ion, or the group ##STR2## R.sub.1 is hydrogen or methoxy; R.sub.2, R.sub.3 and R.sub.5 each is hydrogen or lower alkyl; R.sub.4 is hydrogen, lower alkyl, cyclo-lower alkyl, cyclo-lower alkenyl, cyclo-lower alkadienyl, phenyl, phenyl-lower alkyl, substituted phenyl, substituted phenyl-lower alkyl, or certain heterocyclic groups; R.sub.6 is lower alkyl; and X is hydrogen, lower alkanoyloxy, ##STR3## or certain heterothio groups; are useful as antibacterial agents.

Abstract: Carboxyalkylureido cephalosporins of the formula ##STR1## wherein R is hydrogen, lower alkyl, phenyl-lower alkyl, diphenyl-lower alkyl, tri(lower alkyl)silyl, trihaloethyl, a salt forming ion, or the group ##STR2## R.sub.1 is hydrogen or methoxy; A is straight or branched chain alkylene of 1 to 6 carbons; R.sub.2 is hydrogen, lower alkyl, phenyl, phenyl-lower alkyl, diphenyl-lower alkyl, alkali metal ion or alkaline earth metal ion; R.sub.3 is hydrogen or lower alkyl; R.sub.4 is hydrogen, lower alkyl, cycloalkyl, cycloalkenyl, cycloalkadienyl, phenyl, phenyl-lower alkyl, substituted phenyl, substituted phenyl-lower alkyl, or certain heterocyclic groups; R.sub.5 is hydrogen or lower alkyl; R.sub.6 is lower alkyl; and X is hydrogen, lower alkanoyloxy, ##STR3## or certain heterothio groups; are disclosed. These compounds are useful as antibacterial agents.

Abstract: 7.beta.-[[[(2-Cyanomethyl)amino]-1,2-dioxoethyl]amino]-acyl cephalosporins which have the formula ##STR1## wherein R is hydrogen, lower alkyl, phenyl-lower alkyl, diphenyl-lower alkyl, tri(lower alkyl)silyl, tri(lower alkyl)stannyl, trihaloethyl or a salt forming ion; R.sub.1 is hydrogen, lower alkyl, saturated or unsaturated cycloalkyl, phenyl, phenyl-lower alkyl, substituted phenyl or certain heterocyclic groups; R.sub.2 is hydrogen or methoxy; R.sub.3 is hydrogen, lower alkyl, phenyl-lower alkyl or cycloalkyl; R.sub.4 and R.sub.5 each is hydrogen or lower alkyl; and X is hydrogen, lower alkanoyloxy, carbamoyloxy, lower alkoxy, lower alkylthio ##STR2## or certain heterothio groups, are useful as antibacterial agents.

Abstract: Cyanoalkylureido cephalosporins of the formula ##STR1## wherein R is hydrogen, lower alkyl, phenyl-lower alkyl, diphenyl-lower alkyl, tri(lower alkyl)silyl, trihaloethyl, a salt forming ion, or the group ##STR2## R.sub.1 is hydrogen or methoxy; A is straight or branched chain alkylene or ##STR3## R.sub.2 is phenyl, 2-thienyl, or 3-thienyl; R.sub.3 is hydrogen or lower alkyl; R.sub.4 is hydrogen, lower alkyl, cycloalkyl, cycloalkenyl, cycloalkadienyl, phenyl, phenyl-lower alkyl, substituted phenyl, substituted phenyl-lower alkyl, or certain heterocyclic groups; R.sub.5 is hydrogen or lower alkyl; R.sub.6 is lower alkyl; and X is hydrogen, lower alkanoyloxy, ##STR4## or certain heterothio groups; are disclosed. These compounds are useful as antibacterial agents.

Abstract: [[[(2,4-Dioxo-1-imidazolidinyl)amino]carbonyl]amino]-acetylcephalosporin derivatives having the formula ##STR1## wherein R is hydrogen, lower alkyl, phenyl-lower alkyl, diphenyl-lower alkyl, tri(lower alkyl)silyl, trihaloethyl, a salt forming ion, or the group ##STR2## R.sub.1 is hydrogen or methoxy; R.sub.2, R.sub.3 and R.sub.5 each is hydrogen or lower alkyl; R.sub.4 is hydrogen, lower alkyl, cyclo-lower alkyl, cyclo-lower alkenyl, cyclo-lower alkadienyl, phenyl, phenyl-lower alkyl, substitutted phenyl, substituted phenyl-lower alkyl, or certain heterocyclic groups; R.sub.6 is lower alkyl; and X is hydrogen, lower alkanoyloxy, ##STR3## or certain heterothio groups; are useful as antibacterial agents.

Abstract: Trifluoroalkylureido cephalosporins of the formula ##STR1## wherein R is hydrogen, lower alkyl, phenyl-lower alkyl, diphenyl-lower alkyl, tri(lower alkyl)silyl, trihaloethyl, a salt forming ion, or the group ##STR2## R.sub.1 is hydrogen or methoxy; A is straight or branched chain alkylene of 1 to 6 carbons; R.sub.2 is hydrogen or lower alkyl; R.sub.3 is hydrogen, lower alkyl, cycloalkyl, cycloalkenyl, cycloalkadienyl, phenyl, phenyl-lower alkyl, substituted phenyl, substituted phenyl-lower alkyl, or certain heterocyclic groups; R.sub.4 is hydrogen or lower alkyl; R.sub.5 is lower alkyl; and X is hydrogen, lower alkanoyloxy, ##STR3## or certain heterothio groups are disclosed. These compounds are useful as antibacterial agents.

Abstract: New .alpha.-hydrazinocarbonylamino cephalosporins which have the formula ##STR1## are useful as antimicrobial agents.