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101.
Keiko Takahashi Sayo Morimoto Hiroto Nakamura Toshiaki Narusawa Taizo Seki Masahiko Ooe Keigo Aoi Akiyoshi Takada 《Journal of inclusion phenomena and macrocyclic chemistry》2011,70(3-4):389-396
2-Hydroxypropyl-??-cyclodextrin (HP-??-CyD) includes all-trans retinoic acid (RA), covering the double-bond area of RA with substituted hydroxypropyl groups on CyD ring, as proved by the nuclear Overhauser effect (NOE) between methylene protons on the hydroxypropyl groups and the proton on RA. The formation of an inclusion complex results in hydrophilicity and stability. The effect of RA/HP-??-CyD and that of RA without HP-??-CyD on wrinkle scores and skin elasticity during skin treatment were identical, and the cutaneous stimulus was reduced comparing with RA. The results indicated that the RA/HP-??-CyD complex should help to realize new approaches in skin rejuvenation therapy. 相似文献
102.
Masahiko Takahashi Tsugumasa Takada Takeshi Sakagami 《Journal of heterocyclic chemistry》1987,24(3):797-799
Addition of dihalocarbenes, generated from haloforms using a phase transfer catalyst, to 3H-1,5-benzodi-azepines gave 2H-Bisazirino[1,2-a:2′,1′-d][1,5]benzodiazepines, a new ring system. 相似文献
103.
104.
Masayuki Yamada Sugako Aramaki Tomoo Hosoe Masahiko Kurosawa Isao Kijima-Suda Koichi Saito Hiroyuki Nakazawa 《Analytical sciences》2008,24(7):911-914
Fluoxymesterone, an anabolic steroid with the 17alpha-methyl,17beta-hydroxy group, has been developed as an oral formulation for therapeutic purposes. However, it is also used illegally in racehorses to enhance racing performance. In this study, we detected 9alpha-fluoro-17,17-dimethyl-18-norandrostane-4,13-dien-11beta-ol-3-one by gas chromatography/mass spectrometry (GC/MS), which has not been reported as a fluoxymesterone metabolite so far in horse. It was synthesized for use as a reference standard, and characterized on the basis of (1)H NMR and (13)C NMR spectra, as well as GC/MS EI mass spectra of TMS derivatives. It was excreted as the main metabolite in horse urine, and its reference standard could be synthesized easily. Therefore, this metabolite could be a useful target for a doping test of fluoxymesterone in racehorses. 相似文献
105.
106.
Ali Khumaeni Masahiko Tani Kazuyoshi Kurihara Kiichiro Kagawa Hideaki Niki 《Analytical letters》2017,50(12):1992-1999
A novel method of laser-induced plasma spectroscopy utilizing a pulsed transversely excited atmospheric CO2 laser has been developed for the high-sensitivity determination of heavy metals in soil. A coarse metal powder was used to trap the soil and to assist with plasma generation. When the CO2 laser (10.6?µm, 1.5?J, 200?ns) was irradiated on the metal and soil powder, a high-temperature and long-lifetime luminous plasma was induced. Fine particles of soil were dissociated and were excited in the plasma region. The method was used for the rapid determination of Cr, Pb, and Hg in loam. The limits of detection for Cr, Pb, and Hg were approximately 0.8, 15, and 0.7?mg/kg, respectively. 相似文献
107.
A new method for constructing the polycyclic skeleton of psiguadial B (1), a meroterpenoid isolated from an evergreen shrub of Myrtaceae, was developed. The terpenoid substructure of 1 was constructed on the basis of a cascade double cyclization reaction of an alkyne dicobalt complex, which afforded the bicyclo[4.3.1]decane derivative having a benzyl group with the correct configuration. The substituted aromatic ring was introduced to the bridgehead position of the intermediate, and bromination under radical conditions followed by intramolecular cyclization reaction resulted in formation of the benzopyran moiety in a stereoselective manner. 相似文献
108.
Masahiko Isaka Panida Chinthanom Surisa Kongthong Sumalee Supothina Pataranun Ittiworapong 《Tetrahedron》2010,66(4):955-961
Five new 14-membered macrolides, hamigeromycins C-G, together with the previously described compounds, hamigeromycin A and 89-250904-F1 (radicicol analog A), were isolated from the fungus Hamigera avellanea BCC 17816. Hamigeromycins A, C, D, and E are stereoisomers differing from one another in the absolute configurations of the 4′,5′-diol moiety. Hamigeromycins F and G are unusual 5′-keto-analogs, and they are 6′-epimers to each other. The structures and the stereochemistry of the new compounds were deduced by analyses of the NMR spectroscopic and mass spectrometry data in combination with chemical means. 相似文献
109.
110.
Combined DFT calculations and UV-vis-NIR, ESR, and SQUID measurements revealed that the ground-state electronic structure of a linear π-conjugated oligomer dication composed of two pyrrole and six or seven thiophene rings and methylthio end-capping units is dominated by a singlet biradical character. 相似文献