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51.
Shinzo Kano Tsutomu Yokomatsu Hajime Nemoto Shiroshi Shibuya 《Tetrahedron letters》1985,26(12):1531-1534
A high diastereoselective synthesis of 6-hydroxy-4a-aryl--decahydroisoquinoline derivatives was achieved by an application of N-acyliminium ion-induced polyene cyclization procedure. 相似文献
52.
Mizue Fujio Toshikazu Adachi Yoshifumi Shibuya Akihisa Murata Yuho Tsuno 《Tetrahedron letters》1984,25(40):4557-4560
Substituent effects of p-MeO and p-MeS groups deactivated by additional m-substituents in cumyl and α-phenylethyl solvolyses were studied to provide evidence for the higher resonance demand in the α-phenylethyl system. 相似文献
53.
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55.
Tai-Ichi Shibuya Yasumasa J. I'haya Vincent McKoy 《International journal of quantum chemistry》1975,9(3):505-516
Dynamical screening in π-electron systems is studied by the equations of motion method. By using a partitioning technique on the equations of motion we can obtain simple expressions for the effect of dynamical screening directly on the transition energies and transition moments in π-electron systems. These results are used to study the effect of such screening in the N → V transition in ethylene. This procedure can be used to extend the equations-of-motion method to larger π-electron systems. 相似文献
56.
Akiyo KameyamaYusuke Shibuya Hiroshi KusuokuYoshinori Nishizawa Satoshi NakanoKuniaki Tatsuta 《Tetrahedron letters》2003,44(13):2737-2739
As the first natural product incorporating 1,3-dioxolan-4-one in spiro structure, spilacleosides A and B were isolated from Ruscus aculeatus, and the absolute structures determined. 相似文献
57.
Isao Kitagawa Hirotaka Shibuya Hiromichi Fujioka Yoshio Yamamoto Akiharu Kajiwara Kunihiro Kitamura Ayako Miyao Toshio Hakoshima Ken-ichi Tomita 《Tetrahedron letters》1980,21(20):1963-1966
Acid treatment of (IR, 3S,1′S)-1-(1′,2′-Epoxyethyl)-1,2,2-trimethyl-3-acetoxymethyl-cyclopentane ) has been shown to yield three products (, , ), among which and are 1-oxa-bicyclo[3.3.0]octane derivatives formed successive methyl migrations followed by an oxorane ring closure. 相似文献
58.
The synthesis of 1,1-dimethylcarba-2-penem derivatives via a Dieckmann-type cyclization and the use of a new method for removing the benzyl protecting group are reported. 相似文献
59.
X S Yao Y Ebizuka H Noguchi F Kiuchi M Shibuya Y Iitaka H Seto U Sankawa 《Chemical & pharmaceutical bulletin》1991,39(11):2956-2961
Three phenolic compounds were isolated from the roots of Arnebia euchroma as inhibitors of in vitro prostaglandin biosynthesis. Two known compounds were identified as shikonofurans and des-O-methyllasiodiplodin. The other new compound was named arnebinol and its structure was elucidated as a novel ansa-type monoterpenylbenzenoid derivative. 相似文献
60.
Eiji Tanahashi Katsutoshi Murase Mika Shibuya Yumie Igarashi Hideharu Ishida Akira Hasegawa 《Journal of carbohydrate chemistry》2013,32(6):831-858
Abstract A systematic synthesis of sulfatide (I) and novel sulfatide analogs (II-VI) carrying 2-(tetradecyl)hexadecyl group as a ceramide substitute is described. The 3-O-, 4-O- and 3,4-di-O-levulinoyl derivatives of galactopyranosyl trichloroacetimidates (1, 12, and 13) were coupled with (2S,3R,4E)-3-O-acetyl-2-octadecanamido-4-octadecene-1,3-diol or 2-(tetradecyl)hexadecan-1-ol. The resulting glycolipids (2, 4, 14, and 15) were each transformed, by selective removal of the levulinoyl group(s), and successive sulfation and de-O-acylation, into the 3-sulfates (I, II), 4-sulfate (III), and 3,4-disulfate (IV). The 6-sulfate (V) was prepared from 2-(tetradecyl)hexadecyl β-D-galactopyranoside (21) via the 6-O-t-butyldimethylsilyl derivative, while the 3′-sulfate of 2-(tetradecyl)hexadecyl β-D-lactoside (VI) was synthesized from 2-(trimethylsilyl)ethyl 3′-O-benzyl-β-D-lactoside (26). The structures of the sulfated glycolipids (I-VI) were characterized by ion-spray MS, MS/MS, and 1H NMR spectrometry. 相似文献