Katsuyoshi Shibata

Synthesis of perfluoroalkylated azo dyes and their application to guest-host liquid crystal display

Abstract A series of novel dis- and trisazo dyes containing a perfluoroalkyl, perfluoroalkylthio and perfluoroalkylsulphonyl groups have been synthesized. The absorption bands of these dyes were more bathochromic than the corresponding alkyl derivatives. The solubility of disazo dyes containing perfluoroalkyl and perfluoroalkylthio groups in hexane was larger than the alkyl derivatives. To obtain good dichroism, the azo dyes were required to have a large l/d ratio (>2.50). These novel azo compounds could be used practically as dichroic dyes in guest-host liquid crystal displays.

Fluorine-containing benzothiazolyl bisazo dyes-their application to guest-host liquid crystal displays

Perfluoroalkyl-substituted benzothiazolyl bisazo dyes showed higher solubility and greater bathochromicity than the corresponding alkyl derivatives. These dyes showed good dichroism (order parameter S>0.75).

SYNTHESIS OF AZO CHROMOPHORES CONTAINING A PERFLUOROCYCLO-ALKENYL MOIETY AND THEIR SECOND-ORDER OPTICAL NONLINEARITY

Abstract 1,2-Bis[4-[4-[ N -ethyl- N -(2-hydroxyethyl)amino]phenylazo]phenylthio]perfluorocyclopentene, having two independent intramolecular push-pull chromophores in a molecule, showed the highest second-order nonlinear coefficient ( d 33 ) among the cyclobutenyl, -pentenyl, -hexenyl, and cyclopentenyl nitro derivatives in both doped poly(methyl methacrylate) (PMMA) and polycarbonate (PC).

Second-order optical nonlinearity of 6-(perfluoroalkyl)benzothiazolylazo dyes

Abstract The perfluorobutyl derivative showed a large second-order nonlinear optical coefficient ( d 33 ) and improved relaxation behavior in a series of 6-substituted benzothiazolylazo nonlinear optical chromophores (NLOphores).

An effective synthesis of trifluoromethyl-substituted 1,4-dihydropyridines with phosphorus oxychloride / pyridine adsorbed on silica gel

Abstract Treatment of α-alkoxycarbonyl-α,β-unsaturated trifluoromethyl ketones 1 with β-amino-crotonates 2 affords 2-hydroxy-6-methyl-2-trifluoromethyl-1,2,3,4-tetrahydropyridines 3 , which undergo dehydration by using phosphorus oxychloride / pyridine adsorbed on silica gel, giving good to high yields of 2-methyl-6-trifluoromethyl-1,4-dihydropyridines 4 .

Solubility and decomposition temperature of 1,4-bis(arylamino)anthraquinone dyes

Abstract A series of 1,4-bis(arylamino)anthraquinone dyes have been synthesized. 1,4-Bis(2,5-di-tert-butylanilino)anthraquinone was 200 times more soluble than 1, 4-dianilinoanthraquinone in hexane at 25°C. The decomposition temperatures of the 1,4-bis(arylamino)anthraquinone derivatives were higher than those of 1, 4-diamino- and 1, 4-bis(methylamino)anthraquinones.

N-Aryl-1,8-naphthalimides as highly sensitive fluorescent labeling reagents for carnitine

4-(2-Aminoethylamino)-N-(4-methoxyphenyl)-1,8-naphthalimide can be used as a fluorescent labeling reagent for carnitine. The excitation and emission maxima of this reagent were observed at 436 and 524 nm in acetonitrile, respectively and the reagent reacted smoothly with carnitine to afford the labeled product under mild conditions. The detection limit of carnitine by using this reagent was ca. 30 fmol.

Synthesis of (perfluoroalkylsulfonyl)benzenes

Abstract 4-Substituted (perfluoroalkylsulfonyl)benzenes have been synthesized by the oxidation of 4-substituted (perfluoroalkylthio)benzenes with hydrogen peroxide, anhydrous chromic oxide and potassium permanganate in good yields. 4-(Perfluoroalkylsulfonyl) anilines have been also prepared by the reduction of the corresponding nitrobenzenes.

Highly efficient and stereoselective access to (Z)-α,β-difluoroallyl alcohols and (Z)-α-fluoro-α,β-unsaturated aldehydes based on the reaction of 2,3,3-trifluoro-1-propenyl p-chlorobenzenesulfonate with Grignard reagents

Abstract 2,3,3-Trifluoro-1-propenyl p -chlorobenzenesulfonate ( 1 ), readily available from 2,2,3,3-tetrafluoropropanol, reacted smoothly with various Grignard reagents at 50 °C to afford the corresponding (Z)-α,β-difluoroallyl alcohols 2 in moderate to excellent yields. These alcohols were smoothly hydrolyzed in the presence of a catalytic amount of montmorillonite K10 (Clay) to provide (Z)-α-fluoro-α,β-unsaturated aldehydes 3 in good yields.

SYNTHESIS OF FLUORINE-CONTAINING DISAZO DYES EXTENDED WITH ESTER LINKAGES AND THEIR APPLICATION TO GUEST-HOST LIQUID CRYSTAL DISPLAYS

The solubility of known azo dyes was in the order of dye skeleton: trisazo and aryloxycarbonyl disazo dyes 0.76).