Gist-brocades N.v.

Shell Internationale Research Maatschappij, B.v.

Everardus J Leenderts

Herman H Grootveld

Hendrik A Witkamp

Jan J DeKoning

Jan Verweij

Johannes K Van Der Drift

Henri G Hirs

Jan Verwej

Herwarth Heitman

Paulus B Groen

Hubertus G Walraven

A cephalosporin compound substituted in the 7-position with a (cyclo)alkylideneammonio group of formula (II) ##STR1## wherein X' is an anion from an acid HX, R.sub.1 and R.sub.2 are individually a C.sub.1 -C.sub.16 alkyl group, or R.sub.1 and R.sub.2 together with the carbon atom to which they are attached form a cycloalkylidene ring with up to 8 carbon atoms and a process for the preparation which compounds are useful intermediates.

Cephem derivatives

Process for the preparation of 7.beta.-amino-3-substituted methyl-3-cephem-4-carboxylic acid derivatives, new intermediates comprising 7.beta.-(cyclo)alkylideneammonio-3-halomethyl-3-cephem-4-carbox ylic acid derivatives and 7.beta.-amino/ammonio-3-bromomethyl-3-cephem-4-carboxylic acid derivatives and the processes for the preparation of these intermediates.

Cephalosporin derivatives

A process is disclosed for preparing a 2,2-R.sub.1, R.sub.2 -1,3-dioxolane-4-carboxylic acid or salt thereof rich in either the R or S enantiomer which process comprises

Process for the separation of R and S-2,2-R.sub.1,R.sub.2

Process for the preparation of cephem compounds

The solvate of sodium amoxicillin and N-methyl-2-pyrrolidone and its preparation which is a stable antibiotic from which injectable solutions may be prepared.

Sodium amoxicillin solvate

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Rhoon, Netherlands

Everardus J Leenderts