The invention relates to bimesogenic compounds of formula I

##STR00001##

wherein R.sup.11, R.sup.12, MG.sup.11, MG.sup.12 and CG.sup.1 have the meaning given in claim 1, to the use of bimesogenic compounds of formula I in liquid crystal media and particular to flexoelectric liquid crystal devices comprising a liquid crystal medium according to the present invention.

The invention relates to bimesogenic compounds of formula I

##STR00001##

wherein R.sup.11, R.sup.12, MG.sup.11, MG.sup.12 and CG.sup.1 have the meaning given in claim 1, to the use of bimesogenic compounds of formula I in liquid crystal media and particular to flexoelectric liquid crystal devices comprising a liquid crystal medium according to the present invention.

The present invention provides novel Ruthenium-based transition metal complex catalysts comprising specific ligands, their preparation and their use in hydrogenation processes. Such complex catalysts are inexpensive, thermally robust, and olefin selective.

The present invention provides novel Ruthenium-based transition metal complex catalysts comprising specific ligands, their preparation and their use in hydrogenation processes. Such complex catalysts are inexpensive, thermally robust, and olefin selective.

The present invention provides novel Ruthenium-based transition metal complex catalysts comprising specific ligands, their preparation and their use in hydrogenation processes. Such complex catalysts are inexpensive, thermally robust, and olefin selective.

Process for preparation of MK-7 type of vitamin K2 is characterized by attaching hexaprenyl chain of “all-trans” configuration to monoprenyl derivative of menadiol following “1+6” synthetic strategy. According to the invention, a-sulfonyl carbanion generated in situ from the protected monoprenyl menadiol of the formula (II), wherein R.sub.1 represents C.sub.1-3-alkyl group, is reacted with hexaprenyl halide of the formula (VII), wherein X represents halogen atom, preferably bromine, both Z′ and Z′ represent H or one of Z′ and Z″ represents H and the other represents phenylsulfonyl group —SO.sub.2Ph in the alkylation reaction. The hexaprenyl halide of formula (VII) is obtained by coupling two triprenyl units in alkylation reaction, with or without separation of the intermediates. ##STR00001##

Process for preparation of MK-7 type of vitamin K2 is characterized by attaching hexaprenyl chain of “all-trans” configuration to monoprenyl derivative of menadiol following “1+6” synthetic strategy. According to the invention, a-sulfonyl carbanion generated in situ from the protected monoprenyl menadiol of the formula (II), wherein R.sub.1 represents C.sub.1-3-alkyl group, is reacted with hexaprenyl halide of the formula (VII), wherein X represents halogen atom, preferably bromine, both Z′ and Z′ represent H or one of Z′ and Z″ represents H and the other represents phenylsulfonyl group —SO.sub.2Ph in the alkylation reaction. The hexaprenyl halide of formula (VII) is obtained by coupling two triprenyl units in alkylation reaction, with or without separation of the intermediates. ##STR00001##

Process for preparation of MK-7 type of vitamin K2 is characterized by attaching hexaprenyl chain of “all-trans” configuration to monoprenyl derivative of menadiol following “1+6” synthetic strategy. According to the invention, a-sulfonyl carbanion generated in situ from the protected monoprenyl menadiol of the formula (II), wherein R.sub.1 represents C.sub.1-3-alkyl group, is reacted with hexaprenyl halide of the formula (VII), wherein X represents halogen atom, preferably bromine, both Z′ and Z′ represent H or one of Z′ and Z″ represents H and the other represents phenylsulfonyl group —SO.sub.2Ph in the alkylation reaction. The hexaprenyl halide of formula (VII) is obtained by coupling two triprenyl units in alkylation reaction, with or without separation of the intermediates. ##STR00001##

A process for preparing an S,S′-dialkyldithiocarbonate from a dialkyl disulfide and from a particular metal catalyst, in the presence of carbon monoxide is described in addition to the use of S,S′-dialkyldithiocarbonates as reagents for the preparation of polycarbonates, compounds containing at least one urea and/or isocyanate function and compounds containing at least one thioalkyl function.

A process for preparing an S,S′-dialkyldithiocarbonate from a dialkyl disulfide and from a particular metal catalyst, in the presence of carbon monoxide is described in addition to the use of S,S′-dialkyldithiocarbonates as reagents for the preparation of polycarbonates, compounds containing at least one urea and/or isocyanate function and compounds containing at least one thioalkyl function.