An isomer of fusarubin, 2-acetonyl-5,8-dihydroxy-7-hydroxymethyl-3-methoxy-1,4-naphthoquinone, was prepared from 2-hydroxymethyl-7-(2-hydroxypropyl)-1,4,5,6,8-pentamethoxynaphthalene.
The liquid crystal (LC) mixtures with fused ring systems such as Decahydronaphthalenes and Tetrahydronaphthalenes for reflective or transflective active-matrix liquid crystal display (AM-LCD) have higher durability than LC mixtures with ester-components. These LC mixtures also have some problems such as low nematic-isotropic transition temperature T NI and high driving voltage. The improvement for driving voltage was carried out by using Tetrahydronaphthalene-component with moderate birefringence Dn and large dielectric anisotropy De. However, It was difficult to obtain LC mixtures with sufficiently low driving voltage, because of low T NI and the comparatively high Dn of tetrahydronaphthalene.We have improved these problems by introducing some newly developed LC components and optimization. We obtained the LC mixtures with low Dn and low driving voltage; less than 0.075 of Dn and about 4 V or less of driving voltage. These LC mixtures have high durability with stable nematic phase at low temperature.
Synthesis of a Novel Type of Chiral Phosphinocarboxylic Acids. The Phosphine-Palladium Complexes Catalyzed Asymmetric Allylic Alkylation.-The synthesis of a variety of optically active cyclic phosphinocarboxylic acids is achieved via optical resolution of the racemic compounds using α-methylbenzylamine. The phosphinocarboxylic acids can serve as chiral ligands in the asymmetric alkylation of allylic esters such as (I) or (VI); the high asymmetric induction results from the location of the carboxy group at an appropriate distance from the π-allyl palladium reaction center. The alkylation products obtained are converted into optically active . alpha.-methylene lactones and macrolide derivatives such as (V) (no absolute configurations given).-(OKADA, Y.; MINAMI, T.; UMEZU, Y.; NISHIKAWA, S.; MORI, R.; NAKAYAMA, Y.; Tetrahedron: Asymmetry 2 (
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ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
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