Gist-brocades N.v.

Yamanouchi Europe B.v.

Antoon Van Harrewijn

Peter W Henniger

Aart Muehlenbruch

Robert Heijboer

Tom DeVringer

Stable topical retinoid compositions

1,2,4-Oxadiazolylacetic acid derivatives. The derivatives include penicillin and cephalosporin amides which have antibiotic properties.

Antibacterial 1,2,4-oxadiazolylacetamido cephalosporins

A process for the preparation of acylamido derivatives by reaction of a compound of the formula Z - N = C = O, wherein Z is an optionally substituted alkyl-, aryl- (preferably phenyl or naphthyl) or cycloalkyl or optionally substituted heterocyclic, preferably a penicillanic acid or a cephalosporanic acid nucleus, having carboxyl groups and an optionally present hydroxy group protected, with a carboxylic acid of the formula ##STR1## wherein Z.sup.1 is an optionally substituted hydrocarbon group, in the presence of a catalyst selected from the group consisting of substituted pyridines and their N-oxides, optionally substituted imidazoles or their N-oxides, optionally substituted benzimidazoles or their N-oxides, and optionally substituted imidazo [1,2-.alpha.] pyridines or their N-oxides.

Process for the preparation of heterocyclic compounds

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Delft, Netherlands

Antoon Van Harrewijn