Thermochromism of poly-1-butene gels

Poly-1-butene gels in some solvents of benzene-derivatives show a colouring phenomenon. The colour changes from blue to yellow under irradiation of natural light as the temperature rises from the melting point of the solvent to the sol-gel transition temperature. The colouring phenomenon is due to selective scattering, but not to optical absorption. The apparent characteristics of the phenomenon resemble the thermochromism of cholesteric liquid crystals, although poly-1-butene itself is colourless and has no asymmetric carbons.     

Determination of ethanol in alcoholic beverages by high-performance liquid chromatography-flame ionization detection using pure water as mobile phase

A method for the determination of ethanol in alcoholic beverages by high-performance liquid chromatography-flame ionization detection (HPLC-FID) was developed. An FID system could be directly connected to an HPLC system using pure water as a mobile phase. In a durability test using triacontylsilyl (C30)-silica gel stationary phase for 96 h, no significant change in the retention time of four alcohol compounds was observed. So the HPLC separation of alcoholic beverages was carried out on the C30-silica gel stationary phase. On application to the analysis of six kinds of alcoholic beverages, ethanol could be determined accurately by the proposed method.     

Photo-curable organically modified silicate-phosphate alternating copolymer for photonics applications

Photo-curable vinyl modified silicate-phosphate alternating copolymers were prepared by a direct condensation of organochlorosilane and organophosphoric acid in a solvent-free condition. The obtained copolymers have complete alternating copolymer structure of silicate and phosphate unit, where the main oxo chain consist of –(Si–O–P–O) _n -network. They exhibited an excellent solubility of ionic species such as ionic organic dyes. It was also demonstrated the photo-reduction of Au⁺ ions to form Au nano particles for plasmonics applications. Micro patterns were also fabricated by soft lithographic processes. These results indicate that the photo-curable alternating copolymers are one of promising materials for advanced optical information processing devices.     

Enantioselective total synthesis of (-)- and (+)-petrosin

The enantioselective total synthesis of (-)- and (+)-petrosin is described. The union of two key segments was executed by Suzuki-Miyaura coupling. The quinolizidine rings were stereoselectively constructed via a diastereoselective Mannich reaction and an aza-Michael reaction. The 16-membered ring was constructed by ring-closing metathesis with the second-generation Grubbs catalyst.     

Syntheses of biologically active natural products and leading compounds for new pharmaceuticals employing effective construction of a polycyclic skeleton

Cascade reactions are useful methods for the construction of polycyclic skeletons, which are important cores for biological activities. A variety of cascade reactions carried out under multiple reaction conditions, such as pericyclic, polar, radical, and transition metal-catalyzed reaction conditions, have been investigated. Culmorin, pentalenene, pentalenic acid, deoxypentalenic acid, longiborneol, cedrandiol, 8,14-cedranoxide, atisirene, atisine, and estrane-type steroids were synthesized via the intramolecular double Michael reaction. Aza double Michael reaction was applied to the syntheses of tylophorine, epilupinine, tacamonine, and paroxetine. Furthermore, sequential Michael and aldol reactions were performed in both intramolecular and intermolecular manners, leading to the formation of polycyclic compounds fused to a four-membered ring. Synthesis of paesslerin A utilizing a multicomponent cascade reaction revealed an error in the proposed structure. Unique cascade reactions carried out under radical and transition metal-catalyzed reaction conditions were also investigated. With the combination of several cascade reactions, serofendic acids and methyl 7beta-hydroxykaurenoate, both of which have neuroprotective activity, were synthesized in a selective manner.     

Dihydropyrene annelated with dihydrothieno[3.4-b]pyrazine: synthesis and photoswitching property

In this study, 9,10-diacetoxyl-2,7-di-tert-butyl-trans-10b,10c-dimethyl-10b,10c-dihydropyrene annelated with a dihydrothieno[3.4-b]pyrazine unit (1a) was prepared, for the first time, from 5,13-di-tert-butyl-8,16-dimethyl-1,2,9,10-tetrahydroxy[2.2]metacyclophane and 3,4-diaminothiophene in two steps. The photoisomerization property of 1 was investigated by UV and ¹H NMR spectroscopies, and the quantitative isomerization between the more stable dihydropyrene (DHP) form and the less stable metacyclophane-diene (MCPD) form was observed. A thermally induced return reaction from the MCPD to the DHP form was examined at various temperatures, and the reaction rate was 0.0049 min⁻¹ at 45 °C, which is slower than that of the parent MCPD.     

New strategy for drastic enhancement of selectivity via chemical modification of counter anions in ionic liquid polymer phase

A new strategy for the design of a new chromatographic stationary phase via simple modifications of the counter anions in poly(ionic liquid)-grafted silica phase based on ionic self-assembly technology is proposed. The phase with methyl orange dye as counter anions exhibits ultra-high selectivity towards shape-constrained isomers.     

Homogeneous DNA-detection based on the non-enzymatic reactions promoted by target DNA.

Much effort has focused on methods for detecting various genetic differences in individuals, including single nucleotide polymorphisms (SNPs). SNP can be characterized as a substitution, insertion, or deletion at a single base position on a DNA strand. There is expected to be on average one SNP for every 1000 bases of the human genome, and some variations located in genes are suspected to alter both the protein structure and the expression level. Therefore, highly sensitive techniques with a simple procedure would be desirable for a high-throughput screening of millions of SNPs widely dispersed throughout the human genome. In this short review, we consider recently reported unique techniques for genotyping in a homogeneous solution, and organize them in terms of the chemical and physical processes accelerated on DNA.