Abstract: The invention relates to new 2-oxoazetidines having the formulas ##STR1## where R.sub.1 stands for a lower fluoroalkyl or an optionally protected lower hydroxyalkyl group; R.sub.2 for chlorine, bromine, iodine, fluorine, an ##STR2## group in which n is 0, 1 or 2 and R.sub.5 is a lower alkyl, lower alkenyl, an optionally substituted benzyl group, optionally substituted phenyl group, a --CH.sub.2 COX group in which X means a lower alkyl, lower alkoxy or the amino group, or a ##STR3## group in which Y and Z are the same or different and in each case stand for oxygen, nitrogen or sulphur and R.sub.6 stands for a lower alkyl, lower alkoxy, lower alkylthio, lower dialkylamino, an aryl, aryloxy or arylthio group, or for a group having the formula ##STR4## where W stands for --CH.sub.2 CH.sub.2 --, --CH.dbd.CH-- or C.sub.6 H.sub.4 ; R.sub.3 stands for bromine, chlorine, iodine, SeC.sub.6 H.sub.5 or SC.sub.6 H.sub.5 ; and R.sub.4 stands for hydrogen, a group having the formula ##STR5## in which R.sub.

Abstract: Compounds of formula I ##STR1## wherein, R.sub.1 represents hydrogen or methyl,R.sub.2 represents hydrogen or lower alkyl, lower alkenyl, lower alkynyl or cycloalkyl each of which may be unsubstituted or mono- or poly-substituted by amino, mono- or di(lower)-alkylamino, lower acylamino, carboxy, lower alkoxycarbonyl or carbamoyl; a group of formula IIc(CH.sub.2).sub.p --R.sub.5 IIcwherein R.sub.5 represents phenyl or a 5- or 6-membered saturated or unsaturated heterocycle containing one or more heteroatoms selected from O, S and/or N and which may be unsubstituted or mono- or poly-substituted by fluoro, chloro, bromo, amino, mono- or di-(lower)-alkylamino, hydroxy, lower alkoxy, mercapto, alkylthio, phenylthio, sulfamoyl, guanidino, nitro, cyano, lower acylamino, carboxy, alkoxycarbonyl or carbamoyl and p is 0, 1, 2 or 3; or a group of formula ##STR2## wherein R.sub.6, R.sub.7 and R.sub.8 may be the same or different and each represents hydrogen or lower alkyl or R.sub.6 and R.sub.8 and/or R.sub.

Abstract: 6-(1'-fluorethyl)- and 6-(1'-fluoro-1'-methylethyl)-carbapenems such as (5RS,6RS)-1-aza-6-(1(RS)-fluorethyl)-3-(N'-dimethyl-N'-methylamidinomethyl thio)-7-oxobicyclo[3.2.0]hept-2-ene-2-carboxylic acid which are useful as chemotherapeutic agents in particular as anti-bacterially active anti-biotics.

Abstract: The process for preparing cephalosporanic acid derivatives ##STR1## and salts thereof with bases as well as solvates thereof, comprising reacting a compound of the formula II: ##STR2## wherein R.sub.3 represents hydrogen or an amino protecting group and R.sub.2 represents hydrogen, an easily removable ester group or other carboxyl protecting group, with a compound of formula IIIa, ##STR3## wherein R.sub.1 represents hydrogen, an easily removable ester group or other carboxyl protecting group, and R.sub.4 is a 2-benzothiazol group and salts thereof with bases, and if required removing any ester group or protecting group.

Abstract: Novel compounds of formula I, ##STR1## in which R.sub.1 is hydrogen, alkyl, phenylalkyl, carbalkoxyalkyl, acyl, carboxyalkyl, alkoxyalkyl, hydroxyalkyl, cyanoalkyl, or carbamoylalkyl,R.sub.2 is hydrogen, pivaloyloxymethyl or the residue of an easily splittable ester grouping,R.sub.3 is a pyrazolyl radical, unsubstituted or mono- or di-substituted by alkyl, phenyl, alkoxy, alkylthio, carboxy, carboxyalkyl, carbamoyl, carbamoylalkyl, alkylsulphonyl, azido, acylamino, hydrazino, acylhydrazino alkylidenehydrazino, phenylidenehydrazino, in which the phenyl nucleus is unsubstituted or substituted by NH.sub.2, lower alkoxy or lower alkyl, furylidenehydrazino, carbalkoxy or a group R.sub.5 R.sub.6 N--, in which R.sub.5 and R.sub.6 are the same or different and are hydrogen or alkyl, provided that the nitrogen atoms and the 4-position of the pyrazole nucleus are either unsubstituted or substituted by alkyl, phenyl, or carbalkoxy, andR.sub.

Abstract: 7-[(Carboxymethoximino)-1H-pyrazol-3yl-acetyl]amino-3-desacetoxy-3-(1-methy l-1H-tetrazol-5yl-thio)cephalosporanic acid and salts and solvates thereof which possess chemotherapeutical in particular antibiotic activity.

Abstract: The invention provides novel penicillins and cephalosporins of formula I, ##STR1## methods for their production and their anti-bacterial use.