Hoffmann-la Roche Inc.

Kuno Schleich

Hansjorg Stoller

Martin Schadt

Martin Petrzilka

Georg Trickes

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.

Pyridazines

Decalins of the formula ##STR1## wherein ring A is aromatic or a trans-1,4-disubstituted cyclohexane ring; R.sup.2 is methyl, --CH.sub.2 R', --OR', --CO--R', --CN, --COOH, --CO--OR', --CO--SR' or --O--CO--R'; R.sup.1 is hydrogen, methyl, --CH.sub.2 R, --OR or --CH.sub.2 OR, or when R.sup.2 is methyl, --CH.sub.2 R', --OR' or --CO--R', R.sup.1 also can be --CN, --COOH, --CO--OR, --CO--SR or --O--CO--R; R and R' each are alkyl; and R.sup.1 and R.sup.2 each have up to 12 carbon atoms and together have at most 14 carbon atoms, their racemates and optically active antipodes, are described. Liquid crystalline mixtures comprising Compound I as well as their use in electro-optical devices also are disclosed.

Decalins

There is disclosed a novel process for the preparation of vitamin A acetate whereby .gamma.-acetoxy-tiglic aldehyde is reacted with the salt formed by the reaction of vinyl-.beta.-ionol, triphenylphosphine and an acid.

Novel vitamin A acetate process

Polyene compounds such as vitamin A acetate are prepared by reacting triarylphosphonium salts with aldehydes in a two-phase aqueous-organic solvent system.

Growing community of inventors

Zollikerberg, Switzerland

Kuno Schleich