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761.
Application of solid-phase extraction to the analysis of the isomers generated in biodesulfurization against methylated dibenzothiophenes 总被引:2,自引:0,他引:2
A solid-phase extraction (SPE) technique was applied to analyze and characterize the biodesulfurization reactions against asymmetrically methylated dibenzothiophenes (mDBTs) such as 1-, 2-, 3- and 4-methyldibenzothiophenes present in fossil fuels. Recently, we found that these mDBTs are efficiently degraded by the bacterial strain, Rhodococcus erythropolis KA2-5-1. Separation and concentration of the microbial desulfurization products from each of the mDBTs could be carried out with high efficiency and reproducibility by the SPE procedure. These desulfurization products were identified using the SPE technique combined with GC, GC-atomic emission detection, GC-MS and 1H nuclear magnetic resonance spectroscopy. The analytical data obtained suggested that the desulfurization reactions against mDBTs by this bacterial strain may occur through specific carbon-sulfur bond-targeted cleavages that can be affected by the positions of methyl groups. 相似文献
762.
Fernandez-de-Cossio J Gonzalez J Satomi Y Shima T Okumura N Besada V Betancourt L Padron G Shimonishi Y Takao T 《Electrophoresis》2000,21(9):1694-1699
SeqMS, a software aid for de novo sequencing by tandem mass spectrometry (MS/MS), which was initially developed for the automated interpretation of high-energy collision-induced dissociation (CID) MS/MS spectra of peptides, has been applied to the interpretation of low-energy CID and post-source decay (PSD) spectra of peptides. Based on peptide backbone fragmented ions and their related ions, which are the dominant ions observed in the latter two techniques, the types of ions and their propensities to be observed have been optimized for efficient interpretation of the spectra. In a typical example, the modified SeqMS allowed the complete sequencing of a 31-amino acid synthetic peptide, except for the isobaric amino acids (Leu or Ile, and Lys or Gln), based on only the low-energy CID-MS/MS spectrum. 相似文献
763.
Shimada Y Akane H Taniguchi N Matsuhisa A Kawano N Kikuchi K Yatsu T Tahara A Tomura Y Kusayama T Wada K Tsukada J Tsunoda T Tanaka A 《Chemical & pharmaceutical bulletin》2005,53(7):764-769
To find a new series of arginine vasopressin (AVP) V1A receptor antagonists, the influence of the 2-phenyl group of 2-phenyl-4'-[(2,3,4,5-tetrahydro-1H-1-benzazepin-1-yl)carbonyl]benzanilide (7) was investigated. Replacement of the 2-phenyl group by a 2-ethyl-1H-imidazol-1-yl group was effective in yielding a V1A-selective compound. Moreover, this imidazolyl group was introduced in the same position in YM-35471 (6), and further studies of these compounds were performed. Consequently, we found that the (Z)-4'-({4,4-difluoro-5-[(N-cyclopropylcarbamoyl)methylene]-2,3,4,5-tetrahydro-1H-1-benzazepin-1-yl}carbonyl)-2-(2-ethyl-1H-1-imidazol-1-yl)benzanilide (9f) exhibited highly potent affinity and selectivity, and was the most potent antagonist for the V1A receptor among our compounds. The synthesis and pharmacological evaluation of these compounds are described in this paper. 相似文献
764.
Kouichi Nakagawa Shozo Tero-Kubota Yusaku Ikegami Nobuaki Tsuchihashi 《Photochemistry and photobiology》1994,60(3):199-204
Abstract Sesamolyl and related phenoxyl radicals were studied by conventional and time-resolved electron paramagnetic resonance (EPR) spectroscopic techniques. Continuous UV irradiation of sesamol in benzene produces two types of radicals. Based on the hyperfine coupling values obtained we determined that one is the neutral sesamolyl radical and the others are the dimer radicals. Comparison was made with related compounds, especially 3,4-dime-thoxyphenol. We found that the 3,4-dimethoxyphenoxyl radical had a shorter lifetime than the neutral sesamolyl radical. The EPR results obtained suggest that a near perpendicular orientation of the oxygen p -orbitals with respect to the benzene ring of sesamol makes the radical more stable. This stability may be important for the antioxidant properties. 相似文献
765.
Kotohiro Nomura Hiroshi Okumura Takashi Komatsu Naofumi Naga Yukio Imanishi 《Journal of molecular catalysis. A, Chemical》2002,190(1-2):225-234
Copolymerization of ethylene with styrene using linked cyclopentadienyl-amide titanium(IV) complexes, [Me2Si(C5Me4)(R)]TiCl2 [R=tert-Bu (1), cyclohexyl (2)], and non-bridged (1,3-Me2C5H3)TiCl2(O-2,6-iPr2C6H3) (3)-MAO catalysts have been explored. Although the catalytic activity by 2 was lower than 1, 2 showed more efficient styrene incorporation than 1 under the same conditions. Moreover, the resultant copolymer prepared by 2 possessed completely different microstructure from those by 1, indicating that the nature of amide ligand affects both styrene incorporation and monomer sequence. 相似文献
766.
Kinoyama I Taniguchi N Yoden T Koutoku H Furutani T Kudoh M Okada M 《Chemical & pharmaceutical bulletin》2004,52(11):1330-1333
The search for novel antiandrogens by high-throughput screening (HTS) of the Yamanouchi chemical library led to the discovery of the lead compound (5), which possesses an arylmorpholine moiety. Through the optimization of the lead compound (5), we have found a series of novel arylpiperazine derivatives. Among them, 4-[4-cyano-(3-trifluoromethyl)phenyl]-N-(4-fluorophenyl)piperazine-1-carboxamide (22; YM-92088) exhibited a potent AR antagonistic activity with an IC(50) value of 0.47 microM in the reporter assay, which is more potent than bicalutamide (4) which has an IC(50) value of 0.89 microM. 相似文献
767.
The organometallic multicomponent reaction of alkenyl zirconocene, alkynyl imine, and zinc carbenoid in the presence of dimethylzinc leads to novel C,C-dicyclopropylmethylamines. The formation of intermediate bicyclo[1.1.0]butanes represents the first synthetically useful example of a double C,C-sigma-bond insertion, and the increase in structural complexity from starting materials is highlighted by the formation of nine new C,C-bonds in the final product. 相似文献
768.
Fuyuki Ito Nobuaki Tanaka Akio Katsuki Tsuneo Fujii 《Journal of photochemistry and photobiology. A, Chemistry》2002,150(1-3):153-157
When synthesized flavylium salts (FVs) were allowed to stand in an acetonitrile–water mixture, the color of the solutions changed from yellow to red via green. This color change in FV solution has been studied by observing the change in UV–VIS absorption spectra. In particular, change in the color from green to red depends on the concentration of FV and an amount of water. The solution color, however, changed from red to green on dehydration of the solution. It is concluded that water molecules are responsible for the change in solution color from green to red and the change is due to dimerization and/or aggregation of FVs. 相似文献
769.
Okumura K Nakamura Y Takeuchi S Kato I Fujimoto Y Ikekawa N 《Chemical & pharmaceutical bulletin》2003,51(10):1177-1182
The key intermediate to squalamine, (5alpha,7alpha,24R)-7,24-dihydroxy-cholestan-3-one, was synthesized from the 3-O-acetyl-24R,25-dihydroxy derivative of desmosterol via 10 steps in 16% overall yield and squalamine was also prepared via two further steps in 7.4% total yield from the desmosterol derivative. 相似文献
770.
The ab intio calculation was performed to establish the assignment of the title spectra by such as searching for stationary points belonging to lower excited states. The lowest excited state was confirmed to be of ππ* type with an A″ symmetry of a molecular point group Cs (against the previous assumption of πΣ* type) trapped in deep potential minima at the nonplanar staggered conformation (also against the current belief on the involvement of internal rotation). Thus, lower ‘vibrational’ levels in the S1 state were shown to be tunnel-split levels with various symmetry species for a molecular symmetry group G12. Based on this finding, the spectral data as reported by Philis [Chem. Phys. Lett. 353 (2002) 84] were reassigned while applying the formalism as will be presented in Appendix A. 相似文献