Abstract: A process is described whereby a synthetically produced 4-styryl-cis-3,4-azetidinone is converted to an isocephalosporin or its 2-oxa analog. The process is based upon the condensation of enamine and imine synthons. Novel intermediate azetidinones are also disclosed. Control of the stereochemical course of the process allows economical, high yield preparation of the racemic form of the product or when a single enantiomer of the imine synthon derived from the .beta.-hydroxy-.alpha.-amino acid starting material is used, both enantiomers of the product may be prepared and separated without optical resolution.

Abstract: Novel process for the preparation of .beta.-lactams of the formulae: ##STR1## wherein R' represents lower alkyl, aryl or aryl (lower alkyl), R" represents hydrogen or lower alkyl or R' and R" together with the carbon atoms to which they are attached represent lower cycloalkyl, R'" represents lower alkyl or a group --OR, wherein R represents lower alkyl, X.sub.1, Y.sub.1 and Z.sub.1 are hydrogen or selected organic radicals and R.sub.1 represents an acyl group; which successively involves reacting an 1,3-dicarbonyl compound of the formula: ##STR2## with glycine in the presence of a base to form a vinylamino salt of the formula: ##STR3## wherein M.sub.1.sup.+ is the cation of the base, activating the carboxyl group of said vinylamino salt with an appropriate activating agent and reacting the activated compound in the presence of a tertiary base with an imino compound of the formula: ##STR4## to form the corresponding .alpha.-vinylamino-.beta.-lactam of formula IV A and if desired, subjecting said .beta.

Abstract: Novel .beta.-lactams containing a free carboxylic group of the formula: ##EQU1## wherein A and B are each selected from the group consisting of alkyl, including but not limited to branched alkyl, aryl, aralkyl and monocyclic heterocyclic groups at least one of A and B having a free carboxylic group. Further potential substituents of A and B are members of the group consisting of hydroxy, alkoxy, halogen, nitro, --NH.sub.2, monoalkylamino and dialkylamino groups, X is selected from the group consisting of hydrogen, alkyl, aryl and monocyclic heterocyclic, Y is selected from the group consisting of hydrogen, alkyl and aryl, and Z is selected from the group consisting of alkyl, alkoxy, aryloxy, aralkoxy, alkylthio, arylthio, aralkylthio, --CN, --COO-alkyl and --N.sub.3, useful as antibiotics and for the preparation of polymers and .beta.-amino acids, novel process for their preparation and novel imines used as starting materials for the said .beta.-lactams.