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排序方式: 共有200条查询结果,搜索用时 31 毫秒
1.
Y Sonoda K Ichinose T Yoshimura Y Sato T Sasaki 《Chemical & pharmaceutical bulletin》1991,39(1):100-103
Lanosterol derivatives with a functional group at C-32 have been synthesized from 3 beta-acetoxylanostan-7 alpha-ol. The key reaction of the synthesis is the hypoiodite reaction of 3 beta-acetoxylanostan-7 alpha-ol. In vitro antitumor activity testing of the lanosterol derivatives revealed that 3 beta-hydroxylanost-7-en-32-oic acid has antineoplastic activity. 相似文献
2.
N. Shiran A. Gektin S. Neicheva V. Voronova V. Kornienko K. Shimamura N. Ichinose 《Radiation measurements》2004,38(4-6):459-462
Absorption, emission and thermoluminescence (TL) of as-grown and X-irradiated pure and Ce-doped LiCaAlF6 (LiCAF) and LiSrAlF6 (LiSAF) crystals have been analyzed. It is shown that the energy storage is defined by the dissimilarity of basic matrix properties, intrinsic defect structure, preferred Ce3+ ion disposition and charge compensation defect type. This is the reason of higher colorability and TL efficiency of as-grown Ce:LiSAF compared to Ce:LiCAF. Pre-filling of ultra-deep traps leads to enormous increases in the TL response. Due to these properties Ce:LiSAF and Ce:LiCAF are promising thermoluminescent dosimetric materials. 相似文献
3.
Ichinose H Michizoe J Maruyama T Kamiya N Goto M 《Langmuir : the ACS journal of surfaces and colloids》2004,20(13):5564-5568
Enzyme-based electron-transfer reactions involved in the cytochrome P450 monooxygenase system were investigated in nanostructural reverse micelles. A bacterial flavoprotein, putidaredoxin reductase (PdR), was activated and shown to be capable of catalyzing the electron transport from NADH to electron-carrier proteins such as cytochrome b5 (tCyt-b5) and putidaredoxin (Pdx) in reverse micelles. Ferric tCyt-b5 in reverse micelles was effectively converted to its ferrous form by the exogenous addition of separately prepared reverse micellar solution harboring PdR and NADH. The fact that direct interactions of macromolecular proteins should be possible in the reverse micellar system encouraged us to functionalize a multicomponent monooxygenase system composed of the bacterial cytochrome P450cam (P450cam), putidaredoxin (Pdx), and PdR in reverse micelles. The successful camphor hydroxylation reaction catalyzed by P450cam was significantly dependent on the coexistence of Pdx, PdR, and NADH but not H2O2, suggesting that the oxygen-transfer reactions proceeded via a "monooxygenation" mechanism. This is the first report of a multicomponent cytochrome P450 system exhibiting enzymatic activity in organic media. 相似文献
4.
Makoto OzawaTakaaki Taguchi Takayuki ItohYutaka Ebizuka Kevin I Booker-MilburnG.Richard Stephenson Koji Ichinose 《Tetrahedron》2003,59(44):8793-8798
A novel shunt product was isolated from a disruptant of the actVI-ORFA gene involved in the biosynthesis of actinorhodin (ACT) in Streptomyces coelicolor A3(2). Its structure was elucidated as 1,4-naphthoquinone-8-hydroxy-3-[3(S)-acetoxy-butyric acid], (S)-NHAB, based on NMR, MS, and CD spectroscopic data as well as a single crystal X-ray crystallographic analysis. The formation of (S)-NHAB involves a retro-Claisen type C-C bond cleavage of an ACT biosynthetic intermediate. Feeding experiments with [1-13C] and [2-13C] acetates indicated its biosynthetic origin as a single octaketide chain. The relevant gene product, Act-ORFA, which is a functionally unknown protein, is proposed to play a regulatory role related to the multi-enzymatic steps to ACT production, based on the metabolic profile of its disruptant and the wide distribution of actVI-ORFA homologues in the gene clusters for Streptomyces aromatic polyketides. 相似文献
5.
Optical resolution of new quinolone drugs by capillary electrophoresis with ligand-exchange and host-guest interactions 总被引:3,自引:0,他引:3
A method for the optical resolution of new quinolone drugs (NQs) by capillary electrophoresis has been investigated. The NQs were adequately resolved using a γ-cyclodextrin (γ-CD)-Zn(II)-
-phenylalanine (
-Phe) solution as the running solution. The resolution depended on the components of the running solution and their concentrations. When
-Phe was used instead of
-Phe, inversion of the migration order of the enantiomers was observed. The resolution mechanism is considered to be due to a ligand-exchange interaction of the NQs with Zn(II) and
-Phe, in combination with a host-guest interaction of those with γ-CD. 相似文献
6.
The reactions of beta- and alpha-pyranose peracetates with PCl5 gave products regioselectively chlorinated. The reactions of 1,2,3,4,6-penta-O-acetyl-beta-D-glucopyranose (5) and -beta-D-galactopyranose (6) with PCl5 in CCl4 and that of methyl 2,3,4-tri-O-acetyl-beta-D-glucuronatopyranose (7) with PCl5 in toluene gave 2-O-trichloroacetyl-beta-D-pyranosyl chlorides 4, 12 and 14, respectively, as major products, and alpha-D-pyranosyl chlorides 11, 13 and 15, respectively, as minor products. On the other hand, the reactions of compounds 8 and 9 which were alpha-anomers of 5 and 6, respectively, with PCl5 gave as major products transformed acetyl groups at C-6 to -C(Cl) = CCl2 or -C(Cl)2-CCl3 group (16 and 17 from 8 and 18 from 9). The same reaction of 10, which was alpha-anomer of 7, gave alpha-chloride 15 as a major product. The glycosidation of sugar derivative 4 with sarsasapogenin 23 gave beta-glycoside 24 (29.1%) and alpha-glycoside 25 (46.9%), and that of 12 with 23 gave beta-glycoside 26 (24.0%) and alpha-glycoside 27 (40.8%). The improvement of the yields of beta-glycosides 24 and 26 (66.9 and 62.1% for 24 and 26, respectively) in the glycosidations were accomplished by the employment of alpha-bromides 28 and 29 obtained from 4 and 6, respectively. The glycosidations of monoglycosides 30 and 31 obtained by the treatment 24 and 26, respectively, with ammonia-saturated ether with sugar acetate bromides 32 and 34 gave diglycoside derivatives 35 and 33, respectively. 相似文献
7.
8.
Genki Namba Yuki Mimura Prof. Yoshitane Imai Dr. Ryo Inoue Prof. Yasuhiro Morisaki 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(65):14871-14877
Optically active X-shaped molecules based on the planar chiral [2.2]paracyclophane building block were prepared, in which di(methoxy)terphenyl units were stacked on the central benzene rings. At 25 °C, anisolyl rings freely rotate in solution, while in the crystal form, they are fixed by intramolecular CH–π interactions, thereby leading to the expression of the axial chirality, i.e., propeller chirality was exhibited by the planar chiral [2.2]paracyclophane moiety. The X-shaped molecule exhibited good circularly polarized luminescence (CPL) profiles with moderate ΦPL and a large glum value in the order of 10−3 at 25 °C, in solution. In contrast, at −120 °C, dual CPL emission with opposite signs was observed. According to the theoretical studies, the rotary motion of the anisolyl units is suppressed in the excited states, and so emission from two isomers could be observed. These results demonstrate that the axial chirality was controlled by the planar chirality, leading ultimately to propeller chirality. 相似文献
9.
10.
Takaaki Taguchi Masaki Yabe Hitomi Odaki Miki Shinozaki Mikko Metsä-Ketelä Takao Arai Susumu Okamoto Koji Ichinose 《Chemistry & biology》2013,20(4):510-520
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