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41.
42.
Watanabe M Sue K Adschiri T Inomata H Smith RL Arai K 《Chemical communications (Cambridge, England)》2001,(21):2270-2271
In supercritical water the rate of methanol oxidation was controlled by ionic behavior as follows: the oxidation rate of methanol decreased with increasing proton and hydroxide ion concentration, possibly due to stabilization of the reactant, while that of CO was suppressed by added protons and enhanced by added hydroxide ions. 相似文献
43.
N Kubodera H Watanabe T Kawanishi M Matsumoto 《Chemical & pharmaceutical bulletin》1992,40(6):1494-1499
Six analogues of 1 alpha,25-dihydroxy-22-oxavitamin D3 (OCT) (2), 26,27-dimethyl OCT (5), 26,27-diethyl OCT (6), 24-norOCT (7), 24-homoOCT (8), 24-dihomoOCT (9), and 24-trihomoOCT (10) were synthesized from the 20(S)-alcohol (11) as the common starting material. In the activity inducing differentiation of human myeloid leukemia cells (HL-60) into macrophages, 26,27-dimethyl OCT (5) and 24-homoOCT (8) showed the highest activities. The binding properties of these analogues to the chick embryonic intestinal 1 alpha,25-dihydroxyvitamin D3 (1) receptor are also described. 相似文献
44.
A sensitive and specific method using gas chromatography and negative-ion chemical ionization mass spectrometry is described for the determination of 5-fluoro-2'-deoxyuridine (FdUrd) in plasma. The method is based on the formation of the pentafluoropropionyl derivative of FdUrd and of its stable isotope as internal standard after sample clean-up by solid-phase extraction and purification by high-performance liquid chromatography. Quantification in plasma was possible down to 300 pg/ml. The method was applied to the analysis of plasma levels of FdUrd in mice and dogs. 相似文献
45.
Takaaki Horaguchi Hiroaki Yagoh Kiyoshi Tanemura Tsuneo Suzuki 《Journal of heterocyclic chemistry》1986,23(3):657-663
4,5-Dihydro-3H-naphtho[1,8-bc]furans 4 and 6 which have various substituents (R1 and R2) have been synthesized from 8-oxo-5,6,7,8-tetrahydro-1-naphthyloxyacetic acids 1 and 3 or their ethyl esters 2 . The reaction of acids 1 and 3 with sodium acetate in acetic anhydride gave a mixture of furans 4 and 6 and lactones 5 and 7 . The ratios of the products were varied according to the types of substituents (R1 and R2) in acids 1 and 3 . As the substituent R1 (R2 = hydrogen) in acids 1 was changed from hydrogen to a methyl, ethyl or isopropyl group, production of furans 4 became more difficult. However, when a phenyl group was used as the substituent, furan 4 was obtained in good yield. Similarly, as the substituent R2 (R1 = hydrogen) in acids 1 was changed from hydrogen to a methyl, ethyl or isopropyl group, furan formation was more difficult. In contrast, acids 3 which had electron-withdrawing substituents such as chlorine, bromine or a nitro group at the 4-position afforded furans 6 in good yield. 4,5-Dihydro-3H-naphtho[1,8-bc]furans 4 and 4,5-dihydro-3H-naphtho[1,8-bc]furan-2-carbocylic acids 8 were synthesized from the reaction of esters 2 and potassium hydroxide in dioxane. When the substituents R1 or R2 in esters 2 were varied from hydrogen to a methyl, ethyl or isopropyl group the total yields of furans 4 and furancarboxylic acids 8 were reduced. 相似文献
46.
K Sumoto M Irie N Mibu S Miyano Y Nakashima K Watanabe T Yamaguchi 《Chemical & pharmaceutical bulletin》1991,39(3):792-794
Two pyrazine derivatives [fructosazine (3) and deoxyfructosazine (6)] were simultaneously formed in a solution of D-glucosamine hydrochloride under various conditions. They showed deoxyribonucleic acid (DNA) strand breakage activity in plasmid pBR322 comparable to that of D-glucosamine. The DNA strand breakage by fructosazine (3) was stimulated by Cu2+. 相似文献
47.
Kazuhiro Endo Hideo Ihara Kazuhiro Watanabe Shun-Ichi Gonda 《Journal of solid state chemistry》1982,44(2):268-272
X-Ray photoelectron spectra of TiS3 with a one-dimensional structure were measured. TiS3 may be regarded as Ti4+(S2)2?S2? with pairs of S atoms (S2) and isolated S atoms. The spectra of the sulfur core-levels are assigned by comparison with those of TiS2, where all S atoms are largely separated. The binding energy of the S2 pairs is found to be 1.4 eV higher than that of the isolated S atoms, which is consistent with the larger negative charge of the isolated atoms. The structures of the valence band of TiS3 are discussed in terms of a molecular orbital scheme for the S2 pairs. 相似文献
48.
2-Alkyl-1-alkylthioisoquinolinium salts were readily prepared from 2-alkyl-1(2H)-isoquinolones via 2-alkyl1(2H)-thioisoquinolones in two steps. Under mild conditions, the reaction of 2-alkyl-1-alkylthioisoquinolinium salts with active methylene compounds in the presence of sodium hydride afforded 2-alkyl-1-(substituted methylene)iso-quinolines in good yields. Pyrrolo[2,1-a]isoquinolines were synthesized by the cyclization of 2-benzyl-1-(substituted methylene)isoquinolines using acetic anhydride. 相似文献
49.
Toyohide Takeuchi Mototada Watanabe Tadashi Hamanaka Hiroki Haraguchi Daido Ishii 《Journal of separation science》1990,13(9):606-609
Capillary columns of 0.3-0.5 mm i.d. packed with 3- to 30-μm silica-based stationary phases for liquid chromatography were used for gas chromatographic separation of hydrocarbons. Column efficiencies were evaluated for various commercially available packing material. The best column efficiency was achieved with 5-μm octadecyl group bonded silica gel, the surface of which was coated with a poly (dimethylsiloxane) film. The 30-cm column produced 11,000 theoretical plates. 相似文献
50.
Liquid chromatographic-mass spectrometric analysis for screening of patients with cystinuria, and identification of cystine stone. 总被引:1,自引:0,他引:1
Analyses of amino acids in the urine of a normal human and of patients with heterozygous and homozygous cystinuria have been carried out, using liquid chromatography-mass spectrometry with an atmospheric pressure ionization interface system. A kidney cystine stone was also analysed by this system. Very intense quasi-molecular ions ([M + H]+) of standard cystine, arginine, lysine and ornithine were observed on mass chromatograms as base peaks. Mass chromatograms of the urine samples from a normal human and from patients with heterozygous and homozygous cystinuria were easily distinguishable. The retention times in the mass chromatogram and mass spectrum of kidney stone cystine was almost the same as that of authentic cystine. 相似文献