排序方式: 共有75条查询结果,搜索用时 31 毫秒
1.
Oguchi T Tozuka Y Hanawa T Mizutani M Sasaki N Limmatvapirat S Yamamoto K 《Chemical & pharmaceutical bulletin》2002,50(7):887-891
The solid-state complexation between cholic acid (CA) and either methyl p-hydroxybenzoate (MPB) or ibuprofen (IBP) was investigated. Powder X-ray diffractometry, IR spectroscopy and thermal analysis suggested the complex formation between CA and MPB as well as between CA and IBP by co-grinding method. The stoichiometry of CA-MPB was 1 : 1 while that of CA-IBP was 2 : 1, reflecting the effect of guest size on complex formation. The guest compounds were assumed to be included in the channel of complexes formed by hydrogen bonds among CA molecules. 相似文献
2.
A cross-linked 1,3,5-tristyrylbenzene dendrimer 5 was synthesized to study the photochemical isomerization mechanism. On irradiation, 5 isomerized with the quantum yields (ΦE→Z) of 0.063, which was not very much different from that for a model compound 1 (ΦE→Z 0.080), supporting a volume-conserving hula-twist (HT) mechanism during the photochemical E-Z isomerization. 相似文献
3.
[reaction: see text] A stereoselective total synthesis of (+)-benzastatin E (1) is described. The synthesis involves a diastereoselective Grignard addition to 2-acylindoline 2, which is derived from commercially available (S)-2-indolinecarboxylic acid (3). The unknown absolute configuration of (+)-1 is determined as (9S,10R). 相似文献
4.
Hideaki Iizuka Shoko Watanabe Mayuko Koshikawa Yurie Matsumoto Yuki Aoyama Hideaki Ichiba Toshitaka Nabeshima Takeshi Fukushima 《Analytical and bioanalytical chemistry》2013,405(25):8137-8141
It has been reported that repeated phencyclidine (PCP) treatment induces schizophrenia-like behavior in mice. l-Tryptophan (Trp) concentrations in brain tissues of control (n?=?8) and PCP-treated mice (10 mg/kg/day, s.c., 14 days, n?=?10) were determined using high-performance liquid chromatography (HPLC) with fluorescence detection. The HPLC method involved pre-column fluorescence derivatization with (R)-(?)-4-(N,N-dimethylaminosulfonyl)-7-(3-isothiocyanatopyrrolidin-1-yl)-2,1,3-benzoxadiazole (DBD-PyNCS). Eight different parts of the brain, namely, the frontal cortex, nucleus accumbens, striatum, hippocampus, amygdala, thalamus, hypothalamus, and cerebellum, of both groups were investigated. A significant decrease in the l-Trp concentration in the nucleus accumbens (p?=?0.024) and hippocampus (p?=?0.027) was observed in PCP-treated mice, suggesting that alteration of the l-Trp metabolism might occur in these brain parts. 相似文献
5.
Muhammet Uyanik Naoto Sahara Mayuko Tsukahara Yuhei Hattori Kazuaki Ishihara 《Angewandte Chemie (International ed. in English)》2020,59(39):17110-17117
We report high‐performance I+/H2O2 catalysis for the oxidative or decarboxylative oxidative α‐azidation of carbonyl compounds by using sodium azide under biphasic neutral phase‐transfer conditions. To induce higher reactivity especially for the α‐azidation of 1,3‐dicarbonyl compounds, we designed a structurally compact isoindoline‐derived quaternary ammonium iodide catalyst bearing electron‐withdrawing groups. The nonproductive decomposition pathways of I+/H2O2 catalysis could be suppressed by the use of a catalytic amount of a radical‐trapping agent. This oxidative coupling tolerates a variety of functional groups and could be readily applied to the late‐stage α‐azidation of structurally diverse complex molecules. Moreover, we achieved the enantioselective α‐azidation of 1,3‐dicarbonyl compounds as the first successful example of enantioselective intermolecular oxidative coupling with a chiral hypoiodite catalyst. 相似文献
6.
Control of the efficiency of photoisomerization by oxygen was demonstrated for 1,3,5-tristyrylbenzene dendrimers 1-3; the large dendrons do not significantly affect the photochemistry itself due to volume-conserving isomerization mechanisms but may affect the mobility of the molecules. 相似文献
7.
Tominaga Mai Okajima Mei Yamagishi Mayuko Shinagawa Mitsuru Katsuyama Jun Matsumoto Yoshinori Tomosada Nobuhiro 《Optical Review》2021,28(6):704-715
Optical Review - This paper describes the noise analysis of an electro-optic (EO) sensor system based on experimental and simulation results. We developed a polarization simulator of the EO sensor... 相似文献
8.
Takuya Akatsuka Mayuko Ushiro Shin-ichi Nagamatsu Yoshio Takahashi Takashi Fujikawa 《Polyhedron》2008,27(14):3146-3150
We apply multiple-scattering calculations to the analyses of Sn L3-edge X-ray absorption near-edge structure (XANES) spectra for environmental organotin compounds such as SnCl4−nMen, SnCl4−nBtn, and SnCl4−nPhn (n = 0–4) where Me = CH3, Bt = C4H9, and Ph = C6H5. The XANES peak at 3960 eV has rich information on the local structure. Referring to the optimized structures by density functional theory (DFT) calculations, multiple-scattering calculations well explain the observed spectral changes for different “organic extents”. The present study also supports the widely-used semiempirical rule called ‘Natoli’s rule’ for these environmental compounds, which will be useful to use XANES spectra for the practical analytical tools. 相似文献
9.
Hiraka K Kanehisa M Tamai M Asayama S Nagaoka S Oyaizu K Yuasa M Kawakami H 《Colloids and surfaces. B, Biointerfaces》2008,67(1):54-58
We prepared an anticancer drug based on a pH-sensitive liposome retaining Fe-porphyrin as an SOD mimic. The liposomes contained cationic/anionic lipid combinations and were composed of Fe-porphyrin, 1,2-dimyristoyl-sn-glycero-3-phosphatidylcholine, dimethylditetradecylammonium bromide, sodium oleate, and Tween-80. The Fe-porphyrin was released from the liposome at low pH, and the cytotoxicity for cancer cells by the liposome depended on the acidic environments of the endosomes in the cells. Furthermore, although the liposome exhibited an excellent anticancer effect on a gastric cancer cell line, the SOD activity of Fe-porphyrin was shown to have a significant influence on the cytotoxicity toward cancer cells. These findings suggest that the pH-sensitive liposome retaining the Fe-porphyrin as an SOD mimic promises to be a novel anticancer drug for endosomal escape. 相似文献
10.
Nojima H Takeda-Shitaka M Kanou K Kamiya K Umeyama H 《Chemical & pharmaceutical bulletin》2008,56(5):635-641
Class I major histocompatibility complex (MHC) molecules have three domains, a platform domain and two membrane-proximal immunoglobulin-like domains, an alpha3 domain and a beta2-immunoglobulin (beta2m). To understand the dynamic interactions among the three domains, we simulated the behavior of a partial model deficient in beta2m and another model deficient in the alpha3 domain, by normal mode analysis. As a result, the partial model deficient in beta2m was more flexible in interdomain conformation than the other model. The lowest frequency modes (<2 cm(-1)) observed for the simulations of the partial model deficient in beta2m showed clear interdomain motions as if each domain moved like a rigid body. Such low frequencies and clear interdomain motions were not observed for the simulations of the other model, therefore the interdomain flexibility of the partial model deficient in beta2m may be due to the lowest frequency modes (<2 cm(-1)). These results suggest that beta2m contributes to maintaining the interdomain conformation of class I MHC molecules more than the alpha3 domain does, and may offer convincing evidence to support the notion that the alpha3 domain and beta2m do not have an equal influence on the structural stability of class I MHC molecules. 相似文献