Advanced Materials Research Vol. 830

Abstract: Two synthetic methods based on ZrCl₄-catalyzed and microwave-assisted conditions have been developed for the selective and efficient synthesis of 1,2-disubstituted and 2-substituted benzimidazoles.

Abstract: P¹,P²-Diaciclovir-5'-diphosphate has been synthesized efficiently from aciclovir 5'-H-phosphonate monoester via a one-pot reaction. This method features easily accessible H-phosphonate starting material, short reaction time, and good isolated yield.

Abstract: A general synthesis of nucleoside 5'-phosphoromorpholidates from carboxybenzyl-protected nucleosides has been developed. Phosphitylation, acid-catalyzed hydrolysis, and oxidative coupling generated the phosphomorpholidate products in high yields.

Abstract: Treatment of tert-butyldimethylsilyl (TBDMS) ethers of nucleosides with bromo-trichloromethane (CBrCl₃) in methanol under ultrasonic conditions provides a mild and efficient method for desilylation. The experimental results showed that the employment of ultrasonic could notably improve the reaction efficiency compared with thermal heating condition.

Abstract: A series of α-L-rhamnosyl-1-H-phosphoramidates were synthesized by an efficient oxidative coupling reaction of α-L-rhamnosyl-1-H-phosphonate with amino compounds. All these compounds were characterized with NMR, IR, and MS. This method features simple procedures and high yields.

Abstract: A novel and efficient method for the preparation of AZT 5'-selenophosphoramidates has been developed. Silylation of AZT 5'-H-phosphonamidates, followed by oxidative coupling and hydrolysis afforded 5'-selenophosphoramidates of AZT in good yields.

Abstract: A novel photochromic diarylethene 1-(2-methylbenzothiophene-3-yl)-2- [2-methy-5-(4-methoxyl-3-formyl) phenyl-3-thieny perfluorocyclopentene (1a) has been synthesized. Its properties, including photochromic behavior and fluorescent features, have been investigated in detail. This diarylethene showed good photochromism both in solution and PMMA film and exhibited good fluorescence switching. Its also exhibits optical record property.

Abstract: A new unsymmetrical photochromic diarylethene 1o, which is named 1-(2- methoxyphenyl)-2-[2-methyl-5-(1,3-dioxolane)-3-thienyl]perfluorocyclopentene, was synthesized. Its photochromic and simulated molecule structure were also investigated in detail. This diarylethene underwent reversible photochromism, changing between colorless and blue in hexane solution upon appropriate irradiation with UV/vis light. The kinetic experiments illustrated that the cyclization/cycloreversion process of this compound was determined to be the zeroth/first reaction. In addition, this compound can be used as optical recording materials.

Abstract: A new unsymmetrical photochromic diarylethene 1o, which is named 1-[2-methyl-5-(4-methoxyphenyl)-3-thienyl)-2-{2-methyl-5-[4-methoxyl-3-(2-(1,3-dioxolane)) phenyl]-3-thienyl} perfluorocyclopentene, was synthesized. Its optical properties, including photochromic reactivity, kinetics and fluorescence properties were investigated in detail. The result indicated that the diarylethene underwent reversible photochromism, changing between colorless and blue in hexane solution upon appropriate irradiation with UV light or visible light, respectively. What is more, the kinetic experiments illustrated that the cyclization/cycloreversion process of this compound was determined to be the zeroth/first reaction. In addition, the results demonstrated that the unsymmetrical diarylethene compound 1o had remarkable fluorescence switching properties.

Abstract: A new photochromic diarylethene compound 1,2-(2-ethyl-3-benzofuryl) perfluorocyclopentene was synthesized. And its properties including photochromism, fluorescence both in hexane and solid films were studied. And its absorption maxima were observed at 489 nm in hexane and at 499 nm in PMMA films, respectively, upon irradiation with 313 nm UV light. The fluorescence intensity of diarylethene decreased upon irradiation with 313 nm UV light. And the fluorescence modulation efficiency was better in PMMA films than that in hexane.