1981-90-4Relevant academic research and scientific papers
A facile synthesis of novel liquid crystalline materials having a trifluoromethoxy group and their electro-optical properties
Kanie, Kiyoshi,Takehara, Sadao,Hiyama, Tamejiro
, p. 1875 - 1892 (2007/10/03)
Novel liquid crystals (LCs) containing a trifluoromethoxy group connected to a cyclohexane mesogen or to an alkyl tail were prepared through an oxidative desulfurization-fluorination reaction of the corresponding dithiocarbonates. They were compared with LCs containing a methoxy group with respect to phase transition behavior and physical and electro-optical properties. Most of the CF3O-substituted LCs exhibited in a wide range of temperatures LC phases depending on the type of a mesogenic structure. LCs with a trifluoromethoxycyclohexane mesogen were shown to be thermally more stable than the LCs with a trifluoromethoxybenzene mesogen. LCs having a trifluoromethoxyalkyl tail show physical and electro-optical properties favorable to materials for not only TN-LCDs but TFT-addressed TN-LCDs. Furthermore, 3-β-CF3O-substituted cholestane was shown to be a potential chiral dopant for TFT-addressed TN-LCDs.
A Novel Methylation of Allylic Alcohols Using cis-Dichlorobis(triphenylphosphine)platinum(II)-Tin(II) Chloride Dihydrate Complex Catalyst
Sakamaki, Hiroshi,Kameda, Noriyuki,Iwadare, Tsukasa,Ichinohe, Yoshiyuki
, p. 3491 - 3496 (2007/10/03)
The reaction of allylic alcohols in benzene-methanol (3:2) solvent in the presence of cis-dichlorobis(triphenylphosphine)platinum(II)-tin(II) chloride dihydrate complex catalyst afforded allylic methyl ethers.The structure of the obtained compounds was identified by direct comparison with authentic sample.Cholest-4-en-3α-ol, with a quasi-axial hydroxy group, gave a quantitative yield of 3α-methoxycholest-4-ene.On the other hand, cholest-4-en-3β-ol, with a guasi-equatorial hydroxy group, yielded 3β-methoxycholest-4-ene preferentially, but also yielded 3α-methoxycompound as a by-product, lowering the selectivity of the reaction.
Liquid Crystalline Cholestanyl and Cholesteryl Ether Lipids
Vill, Volkmar,Weber, Nikolaus
, p. 73 - 84 (2007/10/02)
A homologous series of 3β-alyl cholestanyl ethers was prepared and their liquid crystalline properies were studied.The compounds with alkyl groups consisting of n = 3 to n = 20 carbon atoms exhibit a cholesteric phase.In addition, the ethers with alkyl groups consisting of n = 9 to n = 18 carbon atoms show a SA phase.Ordered or tilted smectic phases or blue phases are not observed.The SA phase shows unusual textures several tenths of a degree below the transition to the cholesteric phase.The results obtained are compared with those of 3β-alkyl cholesteryl ethers and other homologous series of cholestanyl derivatives such as cholestanyl esters and cholestanyl carbonates. - Keywords: liquid crystals, cholestanyl ethers, steroidal ether lipids, smectic A*
The invention of radical reactions. Part XXXI. Diphenylsilane: A reagent for deoxygenation of alcohols via their thiocarbonyl derivatives, deamination via isonitriles, and dehalogenation of bromo- and iodo- compounds by radical chain chemistry
Barton, Derek H. R.,Jang, Doo Ok,Jaszberenyi, Joseph Cs.
, p. 7193 - 7214 (2007/10/02)
Various thionocarbonates and xanthates of alcohols and bis-xanthates of vic-diols are readily deoxygenated to the corresponding hydrocarbons or olefins, while bromides and iodides are dehalogenated with diphenylphenylsilane in good yield.
AlCl3-N,N-Dimethylaniline: A Novel Benzyl and Allyl Ether Cleavage Reagent
Akiyama, Takahiko,Hirofuji, Hajimu,Ozaki, Shoichiro
, p. 1932 - 1938 (2007/10/02)
A combination system of AlCl3-N,N-dimethylaniline was found to cleave benzyl ethers readily to give parent alcohols in excellent yields.The system also cleaved allyl as well as methyl ethers.Numerous functional groups such as benzoyloxy, phenylthio, and olefinic double bond were not affected.Comparison of AlCl3-N,N-dimethylaniline and AlCl3-anisole were described.
