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101.
Kosaku Hirota Yoshio Abe Tetsuji Asao Shigeo Senda Yukio Kitade Yoshifumi Maki 《Journal of heterocyclic chemistry》1988,25(3):985-990
Alkaline hydrolysis of 1,3-disubstituted 6-(2-dimethylaminovinyl)uracils 2 induced a novel ring transformation giving 4-alkylaminopyridin-2-ones 3 via ring-opening and ring-closure processes. The 4-methylamino-3-nitropyridin-2-one ( 3a ) thus obtained was employed for the synthesis of 3-deazahypoxanthine derivative 8. 4-Alkylamino-3-cyanopyridin-2-ones 11 , ricinine analogs, were also prepared by the reaction of 4-chloro-3-cyano-1-methylpyridin-2-one ( 10 ) with amines. 相似文献
102.
Abstract— The fluorescence quenching of the indole chromophore by NO− 2 and the fluorescence depolarization of several luminescence probes in aqueous solutions containing hexadecyltrimethylammonium bromide (HDTBr) were measured as a function of added C2 –C4 aliphatic alcohol concentration. The fluorescence decay profiles of pyrene in the micellar solutions were also measured to estimate the aggregation number of the micelles. The addition of n -butyl alcohol significantly reduces the fluorescence quenching rate and the aggregation number and increases the extent of fluorescence depolarization in HDTBr micellar systems. The addition of ethyl alcohol shows a similar but smaller effect. 相似文献
103.
Synthesis and Absolute Configuration at C(8) of ‘p‐Menthane‐3,8,9‐triol’ Derived from (–)‐Isopulegol
Two diastereoisomers of the new, potentially insecticidal ‘p‐menthane‐3,8,9‐triol’ (=(2S)‐ and (2R)‐ 2‐[(1R,2R,4R)‐2‐hydroxy‐4‐methylcyclohexyl]propane‐1,2‐diol; (8S)‐ and (8R)‐ 1 ), have been synthesized from (–)‐isopulegol by both conventional dihydroxylation and catalytic Sharpless dihydroxylation (Scheme). The absolute configuration at C(8) of the corresponding orthoformate adduct (8S)‐ 3a was determined by 1H‐NMR and X‐ray crystallographic analysis (Figure). 相似文献
104.
Yoshifumi Watanabe Hirotaka Yoshiwara Munefumi Kanao 《Journal of heterocyclic chemistry》1993,30(2):445-451
The syntheses of 4-(benzo[b]furan-3-yl)piperidines, 4-(benzo[b]furan-2-yl)piperidines and 4-(benzo[b]thiophen-3-yl)piperidines with 5-HT2 antagonist activity are described. Reaction of 1-acetyl-4-(2,4-difluorobenzo-yl)piperidine 2 with methyl glycolate gave methyl 6-fluoro-3-(1-acetylpiperidin-4-yl)benzo[b]furan-2-carboxylate 3 , which was converted to 2-[2-[4-(benzo[b]furan-3-yi)piperidin-1-yl]ethyl-5,6,7,8-tetrahydro-1,2,4-triazolo-[4,3-a]pyridin-3(2H)-one hydrochloride 9 . Analogous benzo[b]furans 17a-d and benzo[b]thiophenes 10a,b and 18a were prepared by a similar method. Cyclization of 4-fluoro-2-(4-pyridinylmethoxy)acetophenones 20a,b afforded 4-(benzo[b]furan-2-yl)pyridines 21a,b , which were converted to 2-[2-[4-(benzo[b]furan-2-yl)-piperidin-1-yl]ethyl-5,6,7,8-tetrahydro-1,2,4-triazolo[4,3-a]pyridin-3(2H)-one hydrochlorides 24a,b. Among them, benzo[b]furans 9 and 17a,d and benzo[b]thiophenes 10 and 18a showed potent 5-HT2 antagonist activity in vitro. 相似文献
105.
Kazuo Soga Yoshifumi Suzuki Toshiya Uozumi Eiichi Kaji 《Journal of polymer science. Part A, Polymer chemistry》1997,35(2):291-297
Several kinds of MgCl2-supported half titanocene (XTiCl3; X = cyclopentadienyl, pentamethylcyclopentadienyl, indenyl, and heptamethylindenyl) catalysts were prepared and applied to propene polymerization using Al(i-Bu)3a as cocatalyst. It was confirmed from the catalyst analysis that the ligand (X) is attached to titanium even after the reaction with Al(i-Bu)3. When polymerization was conducted without any external donor, those catalysts predominantly gave atactic PP. However, addition of a suitable monofunctional Lewis base like ethylbenzoate caused to change the stereospecificity of polymer from aspecific into highly isospecific. On the other hand, the use of a bifunctional donor like di-n-butylphthalate killed the activity almost completely. The isotactic PP was found to have a microstructure similar to that obtained with metallocene catalysts. © 1997 John Wiley & Sons, Inc. 相似文献
106.
Aromatic aldehydes or ketones which have electron-withdrawing groups on the benzene ring were selectively reduced to the corresponding alcohols in good yields by sodium hydrogentelluride; common aldehydes such as benzaldehyde and tolualdehyde were inert. 相似文献
107.
Kazunori YAMAZAKI Tadashi ITO Yoshihito SAKAI Reiya NISHIO Yohei ITO Yoshifumi MORITA 《Physical Therapy Research》2020,23(2):149
Objective: Many studies have demonstrated that the loss of muscle mass (LMM) poses a risk of postural instability in the elderly; however, few studies have shown how LMM decreases proprioception. In this study, we investigated the changes in postural sway among older individuals with LMM induced by application of a local vibratory stimulus. Method: We enrolled 64 older adults (mean age). Postural sway was measured while applying vibration stimuli of 30, 60, and 240 Hz to both the gastrocnemius and lumbar multifidus muscles. We also measured the relative proprioceptive weighting ratio (RPW) of postural sway. The patients were divided into LMM and non-LMM (NLMM) groups. The study subjects were compared in terms of their age, height, weight, body mass index (BMI), lower leg skeletal muscle mass index (LSMI), L4/5 lumbar multifidus cross-sectional area ratio, and RPW at 30, 60, and 240 Hz. Results: Subjects in the LMM group showed a significantly lower RPW at 60 Hz, LSMI, and BMI than did those in the NLMM group. Conclusions: Decrease in RPW with 60-Hz stimulation concerning the lower leg proprioception is a risk factor for LMM-associated postural instability in the elderly. Consequently, with respect to the gastrocnemius muscles proprioception in LMM, it is necessary to perform assessments using muscle spindle stimuli. 相似文献
108.
109.
Nicolai E. Polyakov Masaharu Okazaki Yoshihisa Fujiwara Yoshifumi Tanimoto Haruhiko Fukaya 《Photochemistry and photobiology》1995,61(6):545-551
The electron spin resonance (ESR) spectra of the transient radical pairs in the photoreduction of 1,5-diphenyl-1,4-pentadiyn-3-one ( I ) and 1,3-diphenyl-2-propyn-1-one ( II ) in sodium dodecyl sulfate (SDS) micellar solutions have been obtained by using the product-yield-detected ESR (PYESR) technique. The PYESR spectra, detected by tracing the microwave effect on the spin-adduct yield as functions of the magnetic field, show the ESR spectra of the ketyl radical of the ketone and SDS radical as the components of the radical pairs. In addition, the growth and the decay processes of the radical pair were observed through detecting the effect of microwave pulse as functions of the delay period between a laser pulse and the off and on time, respectively, of a microwave pulse. The absorption spectra of transient species have also been obtained by using the laser flash photolysis technique. Through the analysis of these data and molecular orbital calculations, the role of acetylenic groups in the photoreactivity of acetylenic ketones is discussed. 相似文献
110.
Vanadium(V) is quantitatively precipitated from aqueous solution with 4-caprinoyl-3-methyl-1-phenyl-5-pyrazolone at pH 1, and collected as a film on a membrane for x-ray fluorescence spectrometry. The limit of detection is ca. 2 μg of vanadium. The procedure gave satisfactory results on standard steels containing 0.003–0.091% vanadium. 相似文献