Showing papers on "Derivative (chemistry) published in 1995"

Efficient interchain photoluminescence in a high-electron-affinity conjugated polymer.

Abstract: We report measurements of photoluminescence efficiency and time dependence in a high-electron-affinity cyano-substituted derivative of poly(p-phenylenevinylene). We find that the luminescence is much longer lived in solid films than in solutions and interpret this result as emission in the film being from an interchain excitation. These results suggest that intermolecular interactions are an important consideration in the design of highly luminescent conjugated polymers.

Stereospecific catalyst system for polymerization of olefins

Abstract: Olefins or mixtures of olefins, particularly propene or mixtures of propene advantageously with ethene, can be polymerized using a Ziegler-Natta catalyst system containing, besides a transition-metal-based procatalyst and cocatalyst which is an organometallic compound, a compound particularly suited for controlling the stereospecificity of the produced polymer. Such a compound called an external donor may also have other effects. By using an acetal derivative of an aldehyde that has two ether groups for this purpose, advantageously selected from the group of dialkoxyphenylalkanes, e.g., dimethoxyphenylpropane, a good stereospecificity of the product is attained combined with the high hydrogen sensitivity of the catalyst system, whereby the use of hydrogen as the chain transfer agent offers an easy control method of the molecular weight of the product by means of adjusting the amount of hydrogen available in the polymerization reaction. If with the acetal derivative donor is used a clearly less hydrogen sensitive donor, e.g. alkoxysilanes, much broader MWD's of the product are achieved.

Phenylanthracene derivative and organic el element

Abstract: PURPOSE:To provide the subject new phenylanthracene derivative having a specified structure, exhibiting a low crystallinity, capable of forming a thin film having a stable amorphous state and useful for, e.g. a light-emitting layer of an organic EL device capable of stably emitting high-brightness blue light. CONSTITUTION:This is a new phenylanthracene derivative having a structure of the formula, A1LA2 (A1 and A2 are each monophenylanthryl or diphenylanthryl; L is a single bond or a divalent bonding group), represented by formula I (R1 and R2 are each an alkyl, a cyclo-alkyl, an aryl, an alkenyl, an alkoxy, an aryloxy, amino or a heterocyclic group; r1 and r2 are each 0 or 1 to 5; L1 is single bond, an arylene, etc.) or formula II (R3 and R4 are each same as R1; r3 and r4 are each 0 or 1 to 5; L2 is same as L1) and useful for, e.g. a light-emitting layer for emitting blue light in an organic EL device. This compound is synthesized by coupling 2-chloro-9,10-diphenylanthracene, etc., in the presence of bis(1,5-cyclooctadiene)nickel, 2,2'-bipyridyl, etc.

Production of aromatic polycarbonate

Abstract: PROBLEM TO BE SOLVED: To obtain an aromatic polycarbonate while reducing material cost by recovering the salicylic ester formed as a result of a termination reaction using a salicylic ester derivative or of a polymerization acceleration reaction and using the salicylic ester derivative produced from the recovered product again. SOLUTION: A salicylic ester and chloroformic ester are subjected to a coupling reaction in the presence of a basic compound to form a crude salicylic eater derivative represented by the formula (wherein R 1 is methyl or ethyl; X is a 1-30C alkyl, a 1-30C alkoxyl, a 6-30C aryl or the like), and this crude product is purified to a chlorine content of 1,000 ppm or below and an alkali metal content of 10 ppm or below. An aromatic dihydroxy compound and a carbonic diester are polycondensed in a molten state to form a prepolymer, the salicylic ester derivative as a terminating agent is added to the system and reacted. The salicylic ester is distilled out to form an aromatic polycarbonate. The distilled salicylic ester is recovered and is used to synthesize a salicylic ester derivative. This derivative is used again as a terminating agent. COPYRIGHT: (C)1998,JPO

Marine bacteria, VIII. Maremycin A and B, new diketopiperazines from a marine Streptomyces sp.

Abstract: In the culture broth of the marine Streptomyces sp. B 9173 the two novel diketopiperazines maremycin A (1) and B (2) were detected by chemical screening. Their structures were elucidated and confirmed by the synthesis of the oxindole derivative 4.

Processes for preparing substituted 1,3-oxathiolanes with antiviral properties

Abstract: Disclosed are processes for preparing compounds of the formula (I) and pharmaceutically acceptable salts or esters thereof: ##STR1## wherein R2 is a purine or pyrimidine base or an analogue or derivative thereof; and Z is S, S═O or SO2. The invention also relates to intermediates of use in the preparation of these compounds.

First structural characterization of silicon–arsenic and silicon–phosphorus multiple bonds in silylated silylidene-arsanes and -phosphanes; X-ray structure of a tellura-arsasilirane derivative

Abstract: The molecular structures of the 1-tert-butyl-1-isityl-3,3,3-triisopropyldisilaphosphene 4(isityl = 2,4,6-triisopropylphenyl), the analogous disilaarsene 5, and the corresponding tellura-arsasilirane 6(formed by reaction of 5 with elemental tellurium) are established by X-ray crystallographic analysis.

Pyrazolo(1,5-a)pyrimidine derivative

Abstract: A pyrazolo[1,5-a]pyrimidine derivative represented by general formula (1) and having such a potent analgesic effect that it is useful as an analgesic, wherein R1 represents hydrogen, lower alkyl, cycloalkyl, thienyl, furyl, lower alkenyl or phenyl; R2 represents naphthyl, cycloalkyl, furyl, thienyl, pyridyl, phenoxy or phenyl; R3 represents hydrogen, phenyl or lower alkyl; R4 represents hydrogen, lower alkyl, lower alkoxy-carbonyl, phenyl-substituted lower alkyl, phenyl or halogen; R5 represents hydrogen or lower alkyl; R6 represents hydrogen, lower alkyl, phenyl-substituted lower alkyl or benzoyl; Q represents carbonyl or sulfonyl; A represents a single bond, lower alkylene or lower alkenylene; and n represents 0 or 1.

Short, Enantiospecific Syntheses of Indolizidines 209B and 209D, and Piclavine A from Diethyl‐L‐Glutamate

Abstract: The 1H-pyrrole derivative obtained from diethyl L-glutamate hydrochloride and tetrahydro-2,5-dimethoxyfuran was cyclized with BBr3 to ethyl (5S)-5,6,7,8-tetrahydro-8-oxoindolizine-5-carboxylate (18). Catalytic hydrogenation of 18 over Pd/C in AcOH gave ethyl (5S,8aR)-octahydroindolizine-5-carboxylate (21), whereas hydrogenation over Rh/Al2O3 in EtOH/AcOH 99:1 afforded mainly ethyl (5S,8S,8aS)-octahydro-8-hydroxyindolizine-5-carboxylate (22). By functional-group interconversions, 21 was transformed into piclavine A (1) and indolizidine 209D (2). Similarly, (5R,8R,8aS)-octahydro-5-pentylindolizine-8-methanol (37), the final relay for indolizidine 209B (3), was obtained from 22.

Difluoroxymethane derivative and liquid crystal composition

Abstract: A difluoroxymethane derivative represented by general formula (I), which is lowly viscous, has a high permittivity anisotropy and is useful as a low-voltage liquid crystal material for various liquid crystal displays (wherein 1, m and n represent each 0 or 1; rings A1 to A3 represent each independently a 6-membered ring such as trans-1,4-cyclohexylene or 1,4-phenylene; Z1 to Z3 represent each independently a covalent bond or a bonding group such as -CH2CH2-; L1 to L4 represent each hydrogen or halogeno; and X represents halogeno, OCF3, etc.). The compound is useful as a low-voltage liquid crystal material of various modes including active matrix and STN systems.

Method of stabilizing an ω-3 unsaturated fatty acid compound

Abstract: A method of stabilizing ω-3 unsaturated fatty acid compounds comprising dispersing one or more compounds selected from a group consisting of an ω-3 unsaturated fatty acid, its derivative and an oil and fat containing the ω-3 unsaturated fatty acid or the derivative in an aqueous solution, is presented. ω-3 Unsaturated fatty acids such as DHA and EPA which have been regarded as unstable can be kept under stable conditions.

Synthesis of a derivative of triangulene; the first non-kekulé polynuclear aromatic

Abstract: The first synthesis of a non-Kekule polynuclear aromatic, a trioxy derivative of triangulene, has been achieved through a two-electron reduction of tetrabutylammonium 4,8-dioxo-4H,8H-dibenzo[cd,mn]pyren-12-olate 14. The single crystal X-ray diffraction structure of this precursor shows it to be essentially planar with a three-fold axis of symmetry. The trioxytriangulene produced when it is reduced also possesses a three-fold axis of symmetry and it has a triplet ground state. The powder ESR spectrum obtained is that for a uniaxial system fitted using the parameters |D/hc|= 0.0064 cm–1, |E/hc|= 0.0000 cm–1. It is stable at room temperature but very sensitive to sir oxidation.

Characterization of an imidazolium compound formed by reaction of methylglyoxal and N-hippuryllysine

Abstract: The 1,3-di-Nα-hippuryllysino-4-methylimidazolium salt 6 has been identified as a major product of reaction of the α-dicarbonyl compound, methylglyoxal 1, with the lysine derivative, Nα-hippuryllysine (Nα-benzoylglycyllysine)2, in phosphate buffer at neutral pH, suggesting a mechanism for crosslinking of protein by 1 and related dicarbonyl compounds during the Maillard reaction.

Self-assembly in organic solvents of a deoxyguanosine derivative induced by alkali metal picrates

Abstract: 3′,5′-Didecanoyl-2′-deoxyguanosine in chlorinated organic solvents undergoes self-assembly mediated by alkali metal picrates which leads to octameric or polymeric species according to the amount of ions present.

Synthesis, Characterization and Crystal Structures of Technetium(V)-Oxo Complexes Useful in Nuclear Medicine. 1. Complexes of Mercaptoacetylglycylglycylglycine (MAG3) and Its Methyl Ester Derivative (MAG3OMe)

Abstract: Mercptoacetylpeptide complexes of {sup 99g}Tc are useful compounds for nuclear medicine. This work describes the synthesis and structural characterization of a mercaptoacetylglyclglycylglycine complex and its esterified analog. Structural characterization is accomplished through NMR, mass spectrometry, and X-ray crystallography.