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111.
The straightforward methodology for the construction of chiral arene-fused-piperidine motifs using a highly enantioselective addition of 2-trityloxymethylaryllithiums to cyclic and acyclic nitroalkenes has been developed. The versatility of the process was highlighted by the first asymmetric synthesis of a dopamine D1 full agonist, A-86929. 相似文献
112.
113.
Dithioacetal monoxides were synthesized from aldehydes and cyclohexanone, and reaction of the dithioacetal monoxides with Grignard reagents was investigated. The dithioacetal monoxide synthesized from alkylaldehyde and 4-chlorobenzenethiol reacted with i-PrMgCl to afford the desired alpha-thiomagnesium in high yield. The generated alpha-thiomagnesium was found to be stable at room temperature and to be useful in organic synthesis. In contrast to this, the dithioacetal monoxides derived from benzaldehyde and cyclohexanone did not give satisfactory results. 相似文献
114.
Yasuhara T Nishimura K Yamashita M Fukuyama N Yamada K Muraoka O Tomioka K 《Organic letters》2003,5(7):1123-1126
[reaction: see text] An omega-nitro-alpha,beta,psi,omega-unsaturated ester underwent a chemoselective conjugate addition of a nitroolefin moiety with aryllithium to produce a psi-aryl-omega-nitro-alpha,beta-unsaturated ester, which was then stereoselectively cyclized by intramolecular nitro-Michael reaction giving a functionalized cyclohexane applicable to the total synthesis of (+/-)-alpha- and beta-lycoranes. 相似文献
115.
Manabu Nakazono Yasuyuki Sato Shigeo Hasegawa Norimasa Arisuda Aiko Miyamoto Kiyoshi Zaitsu 《Chromatographia》2009,70(5-6):933-937
Rapid separation of hydrophobic compounds such as bisindolylmaleimides, indolocarbazoles or fullerene C60 derivatives by ultra performance liquid chromatography was developed. Bisindolylmaleimides and indolocarbazoles were separated within 7 and 5 min, respectively. The linear ranges for the determination of bisindolylmaleimides and indolocarbazoles were 1.25?500 pmol and 0.5?50 pmol per injection (r > 0.99), respectively. Fullerene C60 derivatives were separated within 9 min, and the linear range for the determination of fullerene C60 derivatives was 0.1?10 pmol per injection (r > 0.99). 相似文献
116.
Keiji Yamamoto Kiyoshi Ikeda Leong Kwai Yin 《Journal of organometallic chemistry》1989,370(1-3):319-332
Enantioselective, homogeneous hydrogenation of 3-phenyl-3-butenoic acid (1) has extensively been examined in the presence of the rhodium(I)/4,5-bis[(diphenylphosphino)methyl]-2,2-dimethyldioxolane (DIOP) catalyst systems. Optimization of the reaction conditions was undertaken mainly by controlling effects of added tertiary amines as well as solvent polarities on the enantio-selectivity of the product. The best asymmetric yield (85.1% e.e.) was attained when the hydrogenation was carried out in the presence of triethylamine (5 mol%) in 75% aqueous methanol using a neutral rhodium-DIOP catalyst. 相似文献
117.
Akiko Ohno Nana Kawasaki Kiyoshi Fukuhara Haruhiro Okuda Teruhide Yamaguchi 《Magnetic resonance in chemistry : MRC》2010,48(2):168-172
Complete NMR analysis of oxytocin (OXT) in phosphate buffer was elucidated by one‐dimensional (1D)‐ and two‐dimensional (2D)‐NMR techniques, which involve the assignment of peptide amide NH protons and carbamoyl NH2 protons. The 1H? 15N correlation of seven amide NH protons and three carbamoyl NH2 protons were also shown by HSQC NMR of OXT without 15N enrichment. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
118.
119.
Kiyoshi Ando 《Journal of Graph Theory》2009,60(2):99-129
An edge of a 5‐connected graph is said to be contractible if the contraction of the edge results in a 5‐connected graph. Let x be a vertex of a 5‐connected graph. We prove that if there are no contractible edges whose distance from x is two or less, then either there are two triangles with x in common each of which has a distinct degree five vertex other than x, or there is a specified structure called a K4?‐configuration with center x. As a corollary, we show that if a 5‐connected graph on n vertices has no contractible edges, then it has 2n/5 vertices of degree 5. © 2008 Wiley Periodicals, Inc. J Graph Theory 60: 99–129, 2009 相似文献
120.
Takaaki Horaguchi Eietsu Hasegawa Takahachi Shimizu Kiyoshi Tanemura Tsuneo Suzuki 《Journal of heterocyclic chemistry》1989,26(2):365-369
Cyclohepta[cd]benzofuran 2 was synthesized by heating (5-oxo-5H-benzocyclohepten-4-yloxy)acetic acid 16 with sodium acetate in acetic anhydride or by photocyclization of 16 in acetonitrile. Several reactions of cyclohepta[cd]benzofuran 2 were examined. Protonation of 2 with trifluoroacetic acid occurred at the 2-position to give a tropylium ion 17 . Catalytic hydrogenation of 2 with palladium on charcoal proceeded smoothly to give tetrahydrocyclohepta[cd]benzofuran 18 . The Diels-Alder reaction of 2 with tetracyano-ethylene produced an adduct 19 . Formylation of 2 with phosphorus oxychloride and dimethylformamide occurred easily at the 2-position to afford compound 20 . Cyclohepta[cd]benzofuran 2 has both properties of heptafulvene and benzofuran. 相似文献