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991.
Imbiline 1 (1a), a constituent of Eupomatia species, was synthesized from 4-methoxy-1-naphthylamine hydrochloride (8) in seven steps. A reaction of aldehydes and methyl methylthiomethyl sulfoxide was also studied. 相似文献
992.
The mode of action of protopine on blood platelet aggregation was investigated in the metabolic system of arachidonic acid and in liberation of platelet activating factor using in vitro experimental models. Protopine inhibited the releases of arachidonic acid and platelet activating factor from platelet membrane phospholipids. Protopine also inhibited the conversion of prostaglandin G2 to thromboxane A2, as well as carboxyheptyl imidazole, a thromboxane synthetase inhibitor. These results indicated that protopine functions both as a phospholipase inhibitor and a thromboxane synthetase inhibitor. It is expected that protopine can be applied for treatment of thrombosis as an antiplatelet drug. 相似文献
993.
Y Nomoto H Obase H Takai T Hirata M Teranishi J Nakamura T Ohno K Kubo 《Chemical & pharmaceutical bulletin》1990,38(9):2467-2471
A series of 1-[1-(6,7-dimethoxy-4-quinazolinyl)-4-piperidinyl]-3-substituted 2-imidazolidinone and 2-imidazolidinethione derivatives was synthesized and examined for cardiotonic activity in anesthetized dogs. Alkylation of the 2-imidazolidinone (1) afforded the N-alkylated products, while alkylation of the 2-imidazolidinethione (12) afforded the S-alkylated derivatives accompanied with a small quantity of the N-alkylated products. The N-alkylated derivatives showed generally potent activity, and the S-alkylated ones exhibited weak activity. Insertion of an alkyl group between the piperidine and the imidazolidinone moiety generally resulted in a fall in activity. 相似文献
994.
Sakaguchi S Mizuta T Furuwan M Kubo T Ishii Y 《Chemical communications (Cambridge, England)》2004,(14):1638-1639
The coupling of amines, aldehydes and trimethylsilylacetylene was found to be promoted in the presence of a catalytic amount of [IrCl(cod)]2; 1 : 1 : 1 or 1 : 2 : 2 coupling products were obtained by allowing primary amine to react with aldehyde and trimethylsilylacetylene. 相似文献
995.
Motohiko Hikuma Tatsuru Kubo Takeo Yasuda Isao Karube Shuichi Suzuki 《Analytica chimica acta》1979,109(1):33-38
A microbial sensor consisting of immobilized Trichosporon brassicae, a gas-permeable Teflon membrane and an oxygen electrode is suitable for the continuous determination of acetic acid in fermentation broths. When an acetic acid solution is pumped through the flow system, the current decreases to a steady state with a response time of 8 min; shorter pumping times give peaks which can also be measured. The relationship between the current decrease and the acetic acid concentration is linear up to 54 mg l-1, with a relative standard deviation of about 6% at the higher concentrations. Selectivity is satisfactory. Results obtained with this sensor and by gas chromatography for a glutamic acid fermentation broth were in good agreement (regression coefficient 1.04). The sensor was stable for more than 3 weeks and 1500 assays. 相似文献
996.
Fenitrooxon [O,O-dimethyl-O-(4-nitro-m-tolyl)phosphate] is the major metabolite of the organophosphorus insecticide fenitrothion, and 3-methyl-4-nitrophenol is its major degradation product. In the present study, we describe the development of an indirect competitive enzyme-linked immunosorbent assay (ELISA) for the detection of these compounds in water samples based on a group-specific polyclonal antiserum generated with a “bifunctional hapten”, which has two functions: the conventional function of producing an antibody against an antigen and a unique function of promoting the production of the antibodies in rabbit. For application to water samples, the influence of several factors such as organic solvent, pH, and detergent was studied. Under optimized conditions, the quantitative working range of the fenitrooxon ELISA was 0.71-27 ng ml−1 with a limit of detection (LOD) of 0.32 ng ml−1, and the fenitrooxon concentration giving 50% reduction of the maximum signal (IC50) was 4.2 ng ml−1. The quantitative working range of the 3-methyl-4-nitrophenol ELISA was 0.67-27 ng ml−1 with a LOD of 0.38 ng ml−1 and an IC50 of 3.7 ng ml−1. No significant matrix effect originating from the water sample (river water, tap water, purified water, and bottled water) was shown by addition of Tween 20 to the assay buffer. Water samples spiked with each of these compounds at 1, 5, 10, and 20 ng ml−1 were directly analyzed without extraction and clean-up by the proposed ELISA. The mean recovery was 100.9%, and the mean coefficient of variation (CV) was 7.7% for the fenitrooxon ELISA and for the 3-methyl-4-nitrophenol ELISA, the mean recovery was 97.6%, and the mean CV was 7.2%. The proposed ELISA allows precise and accurate determination of these compounds in water at such low levels. 相似文献
997.
Syun-ichi Kiyooka Hiroko Sasaoka Ryoji Fujiyama Clayton H. Heathcock 《Tetrahedron letters》1984,25(46):5331-5334
1,3-Syn diastereofacial selectivity (2.8 : 1) has been found in the titanium tetrachloride — titanium tetra-isopropoxide mediated reaction of allylsilane with β-alkoxy acetal 2. 相似文献
998.
Cyclodextrin-modified micellar electrokinetic chromatography was applied to the enantioseparation of catechin and epicatechin using 6-O-alpha-D-glucosyl-beta-cyclodextrin together with sodium dodecyl sulfate and borate-phosphate buffer. Factors affecting chiral resolution and migration time of catechin and epicatechin were studied. The optimum running conditions were found to be 200 mM borate-20 mM phosphate buffer (pH 6.4) containing 25 mM 6-O-alpha-D-glucosyl-beta-cyclodextrin and 240 mM sodium dodecyl sulfate with an effective voltage of +25 kV at 20 degrees C using direct detection at 210 nm. Under these conditions, the resolution (Rs) of racemic catechin and epicatechin were 4.15 and 1.92, respectively. With this system, catechin and epicatechin enantiomers along with other four catechins ((-)-catechin gallate, (-)-epicatechin gallate, (-)-epigallocatechin, (-)-epigallocatechin gallate) and caffeine in tea samples were analyzed successfully. The difference of migration time between catechin and epicatechin is discussed. 相似文献
999.
3-hydroxyflavone in the vapor phase exhibits long-wavelength flourescence (λmax = 530 nm) due to a tautomer generated by intramolecular excited-state proton transfer. Excitation energy dependence on the flourescence quantum yield and lifetimes of the tautomer was observed suggesting proton transfer in the upper vibrational S1 state of 3-hydroxyflavone. 相似文献
1000.
Yukari Okuwaki Yukiko Inagawa Hideo Tamamura Taeko Suzuki Hiroko Kuwana Mika Tahara Kayo Yuasa Akihiro Ohta 《Journal of heterocyclic chemistry》1987,24(1):187-190
3,6-Dialkyl-2-hydroxypyrazine 1-oxides were found to be useful as acyl carriers. Benzoyl derivatives were convenient reagents for benzoylation of amines and hydroxy compounds. 相似文献