Synthesis and properties of (E)-1,2-difluoroethylene derivatives: improvement of the ultraviolet light stability

The synthesis and properties of (E)-α,β-difluorostilbene derivatives were studied. In particular, we investigated three suppression methods of (E)–(Z) isomerisation by shortening the molecular conjugation length, which included the introduction of a fluorine atom into the ortho or para position of the benzene ring or the replacement of the benzene ring with a cyclohexane ring. The relationship between the molecular structure of liquid crystals and the level of isomerisation by ultraviolet (UV) light was discussed.     

Phosphorylation of Amine Compounds with Sodium Cyclo-triphosphate

Abstract

Among inorganic linear and cyclic phosphates, cyclo-triphosphate has drawn special attention for its high reactivity with various amine compounds. A ring opening reaction to produce N-alkylamidotriphosphate derivatives proceeds under moderate conditions, e.g., at room temperature in aqueous solution. In spite of its potentiality as a phosphorylating agent for amino groups, a systematic investigation on the reaction mechanism has not fully carried out. This may be due to the lack of analytical methods which allow the quantitative examination of the reactions. In this work, HPLC with an anion-exchanger column developed for phosphate compounds together with ³¹P-NMR were applied to a kinetic study. It has been clarified that; 1) the reactivity of amine compounds is primarily correlated with the basisity of the amino groups, i.e., pKa values of its conjugate acids, though, branching at α carbon of the amino group greatry retards the reaction rate because of steric hindrance, and 2) some bifunctional reagents, such as ethylenediamine, propanediamine, ethanol-amine, and some α-amino acids produce heterocycles which contain P-N bond through an intramolecular reaction following the ring opening of cyclo-triphosphate. Ba or Mg salts of N-alkylamidotriphosphate derivatives have been prepared from mono amines, diamines, aminoalcohols, and aminoacids.     

QSNPlite, a software system for quantitative analysis of SNPs based on capillary array SSCP analysis

We present a newly developed software called "QSNPlite" that comprehensively interprets the data of SSCP and sequencing analyses obtained from capillary array electrophoresis systems used in the quantitative characterization of SNPs. QSNPlite assists in the genotyping of individuals with SNPs and in estimating the allele frequencies of SNPs using pooled DNA. We show that this estimation is accurate (mean absolute error, 1.4%) by comparing the results of the pooled analysis using QSNPlite with the true frequencies based on the allele counting after performing individual genotypings. The QSNPlite program runs on Windows XP and can be used to determine the allele frequencies of SNPs among a large number of individuals, such as in association studies of disease-responsible genes using the candidate gene approach.     

Reduction of a mean ergodic Markov semigroup onC(X) into its irreducible components

Communicated by R. Nagel     

A single-strand conformation polymorphism method for the large-scale analysis of mutations/polymorphisms using capillary array electrophoresis

We present a high-throughput single-strand conformation polymorphism (SSCP) method, performed on a commercially available capillary array DNA sequencer. We tested various sieving matrices and electrophoretic conditions, using 51 DNA fragments which included 45 fragments carrying only one single nucleotide polymorphism (SNP), 4 fragments having two SNPs and 2 fragments with insertion or deletion. Resolution of alleles was improved by increasing concentrations of both sieving matrices and buffers, and all examined polymorphisms of DNA fragments were detected, most of them (45 fragments) as clearly split allele peaks in heterozygotes. Allele frequencies of SNPs can be estimated accurately by determining the relative amounts of alleles in pooled DNA. In this method, the turn-around time for the analysis of 96 samples is less than 3 h. These results demonstrate that capillary array-based SSCP is an efficient and accurate technique for the large-scale quantitative analysis of mutations/polymorphisms.     

Porous Mn2+ Magnet with a Pt−Cl Framework: Correlation between Water Vapor Adsorption/Desorption and Slow Magnetic Relaxation

We report the water adsorption/desorption behavior and dynamic magnetic properties of the Pt−Cl chain complex [{[Pt(en)₂][PtCl₂(en)₂]}₃][{(MnCl₅)Cl₃}₂] ⋅ 12H₂O ( 1 ). Upon heating 1 in a vacuum, we obtained the dehydrated form [{[Pt(en)₂][PtCl₂(en)₂]}₃][{(MnCl₅)Cl₃}₂] ( 1DH ). The framework structures of 1 and 1DH are identical, and both complexes underwent slow magnetic relaxation. However, the magnetic relaxation times for 1DH were shorter than those for 1 , meaning that the dynamic magnetic properties were controlled upon water vapor adsorption/desorption. From detailed analyses of the dynamic magnetic behavior, a phonon-bottleneck effect contributes to the magnetic relaxation processes. We discuss the mechanism for the changes in the magnetic relaxation processes upon dehydration in terms of the heat capacity and thermal conductivity.     

Synthesis of Mannosylerythritol Lipid Analogues and their Self-Assembling Properties,Recovery Effects on Damaged Skin Cells,and Antibacterial Activity

Synthesis of three types of purpose-designed mannosylerythritol lipid (MEL)-D analogues with decanoyl groups, β-GlcEL-D, α-GlcEL-D, and α-MEL-D, was accomplished utilizing our boron-mediated aglycon delivery (BMAD) methods. Their self-assembling properties, recovery effects on damaged skin cells, and antibacterial activity were evaluated. It was revealed, for the first time, that α-GlcEL-D and α-MEL-D only generated giant vesicles, indicating that slight differences in the steric configuration of an erythritol moiety and fatty acyl chains affect the ability to form vesicles. Analogue α-MEL-D exhibited significant recovery effects on damaged skin cells. Furthermore, α-MEL-D exhibited antibacterial activity as high as that for MEL-D, indicating that α-MEL-D is a promising artificial sugar-based material candidate for enhancing the barrier function of the stratum corneum, superior to a known cosmetic ingredient, and possesses antibacterial activity.     

Simultaneous Spin-Crossover Transition and Conductivity Switching in a Dinuclear Iron(II) Coordination Compound Based on 7,7′,8,8′-Tetracyano-p-quinodimethane

The reaction of Fe(OAc)₂ and Hbpypz with neutral TCNQ results in the formation of [Fe₂(bpypz)₂(TCNQ)₂](TCNQ)₂ ( 1 ), in which Hbpypz=3,5-bis(2-pyridyl)pyrazole and TCNQ=7,7′,8,8′-tetracyano-p-quinodimethane. Crystal packing of 1 with uncoordinated TCNQ and π–π stacking of bpypz⁻ ligands produces an extended two-dimensional supramolecular coordination assembly. Temperature dependence of the dc magnetic susceptibility and heat capacity measurements indicate that 1 undergoes an abrupt spin crossover (SCO) with thermal spin transition temperatures of 339 and 337 K for the heating and cooling modes, respectively, resulting in a thermal hysteresis of 2 K. Remarkably, the temperature dependence of dc electrical transport exhibits a transition that coincides with thermal SCO, demonstrating the thermally induced magnetic and electrical bistability of 1 , strongly correlating magnetism with electrical conductivity. This outstanding feature leads to thermally induced simultaneous switching of magnetism and electrical conductivity and a magnetoresistance effect.