Abstract: The present invention is concerned with a novel process for the manufacture of cephalosporin derivatives of the formula by converting a phosphonium salt into the corresponding ylide and reacting same with an aldehyde wherein R1 and R2 are as above.

Abstract: Crystalline sodium 2.alpha.-methyl-2.beta.-(1,2,3-triazol-1-yl) -methylpenam-3.alpha.-carboxylate-1,1-dioxide monohydrate (crystalline tazobactam sodium monohydrate) obtainable by adding to a concentrated aqueous solution of sodium 2.alpha.-methyl-2.beta.-(1,2,3-triazol-1-yl)-methylpenam-3.alpha.-carboxyl ate-1,1-dioxide (tazobactam sodium) a solvent selected from acetone and ethanol in an amount corresponding to a solvent to water ratio of between about 95:5 and 99:1 v/v and crystallizing the desired product from the solvent mixture. The crystalline tazobactam sodium monohydrate exhibits a high .beta.-lactamase inhibitory activity in combination with .beta.-lactam antibiotics.

Abstract: Compounds of the formula ##STR1## wherein B is --C.tbd.C-- or --CH.sub.2 CH.sub.2 --, R.sup.1 is straight-chain C.sub.1 -C.sub.12 -alkyl and R.sup.2 is straight-chain C.sub.1 -C.sub.12 -alkyl or straight-chain C.sub.1 -C.sub.12 -alkoxy, their manufacture and use in liquid crystalline mixtures are described.

Abstract: Compounds of the formula ##STR1## wherein R.sup.1 is straight-chain alkyl of 1 to 12 carbon atoms, R.sup.2 is alkyl, alkoxy, p-alkylphenyl, p-alkoxyphenyl or trans-4-alkylcyclohexyl, and the alkyl and alkoxy groups in R.sup.2 each are straight-chain groups of 1 to 10 carbon atoms,their manufacture, liquid crystalline mixtures containing said compounds as well as their use for electro-optical purposes are described. The novel compounds are valuable components for liquid crystalline mixtures and have a negative dielectric anisotropy.