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11.
Masao Nohara Masaki Hasegawa Hatsuhiko Harashina Yoichi Iitaka 《Journal of polymer science. Part A, Polymer chemistry》1988,26(10):2695-2704
Photoreactive polyamides having m- or 1 -type cyclobutane moiety were prepared via a topochemical photodimerization of 4-(3-oxo-3-phenyl-1-propenyl)benzoic derivatives,4 followed by polycondensation of cyclobutane dicarboxylate derivatives with diamines. From the spectral studies of resulted polyamides compared with the corresponding reference diamides, it was concluded that both types of polyamides were depolymerized photochemically to give the same type of amide derivative having chalcone moiety with a small amount of undefined side reaction. The cyclobutane ring of the m-dimer from 4-(3-oxo-3-phenyl-1-propenyl)benzoic acid in crystal is severely twisted presumably because of the enhanced steric repulsions between two pairs of adjacent substituents. The higher quantum yield of the m-dimer for the photocleavege, compared with that of the 1 -dimer, has been interpreted in terms of such steric repulsions by the strained structure of the m-dimer. 相似文献
12.
Four new cycloartane glycosides from Aquilegia vulgaris 总被引:2,自引:0,他引:2
Four new cycloartane glycosides, named aquilegiosides G-J, were isolated from the dried aerial parts of Aquilegia vulgaris. Their structures were determined by spectroscopic analysis and chemical evidence. 相似文献
13.
2-Arylamino-4,6-dichloro-s-triazine reacts with cyanuric chloride in the presence of alkali to yield N,N-bis(4,6-dichloro-s-triazin-2-yl)-arylamine. In like manner, 2-substituted o-chloro-, p-chloro-, o-nitro- and p-carbomethoxyphenylamino-4,6-dimethoxy-s-triazines react with cyanuric chloride to yield the corresponding 4,6-dichloro-s-triazin-2-yl-4′,6′-dimethoxy-s-triazin-2′-ylaryl-amine, while anilino-, p-toluidino, o- and p-methoxyphenylamino and o-carbomethoxyphenylamino derivatives did not. The reaction of cyanuric chloride with 2,4-dichloro-6-ethylamino-s-triazine in the presence of alkali yields the condensation product of the ditriazinylamine type and the reaction of cyanuric chloride with ammonia yields N,N-bis(4,6-dichloro-s-triazin-2-yl)- or tris(4,6-dichloro-s-triazin-2-yl)amine. 相似文献
14.
Steroidal oligoglycosides from Solanum nigrum 总被引:5,自引:0,他引:5
Two new steroidal saponins, named nigrumnins I and II, together with two known saponins were obtained from the whole plant of Solanum nigrum L. On the basis of spectroscopic analysis (1H-NMR, 13C-NMR, 1H-1H COSY, TOCSY, HMQC, HMBC and FAB-MS), nigrumnin I was established as (25R)-5alpha-spirostan-3beta-ol 3-O-betaD-xylopyranosyl-(1-->3)-[alpha-L-arabinopyranosyl-(1 -->2)]-beta-D- glucopyranosyl-(1-->4)-[alpha-L-rhamnopyranosyl(1-->2)]-beta-D- galactopyranoside (1), and nigrumnin II was elucidated as (25R)-3beta,17alpha-dihydroxy-5alpha-spirostan-1 2-one 3-O-beta-D-xylopyranosyl-(1-->3)-[alpha-L-arabinopyranosyl-(1--> 2)]-beta-D-glucopyranosyl-(1-->4)-[alpha-L-rhamnopyra- nosyl-(1-->2)l-beta-D-galactopyranoside (2). 相似文献
15.
Yukie Nakamura 《Tetrahedron》2007,63(28):6383-6387
Chiral Ru(salen)(nitrosyl) complex 1 is a useful catalyst for asymmetric aerobic oxidation of alcohols under photo-irradiation. In this study, it was found that addition of β-hydroxy ketone or 1,3-diketone had a significant influence on its asymmetric catalysis. For example, the addition of 1,3-bis(p-bromophenyl)propane-1,3-dione 9 improved the relative reaction ratio in kinetic resolution of simple racemic secondary alcohols up to 30, while the addition gave an adverse effect on desymmetrization of an acyclic meso-1,3-diol. This additive effect was considered to be attributable to the chelate formation of the β-hydroxy ketone or 1,3-diketone with a Ru(salen) complex. 相似文献
16.
Sato H Takase R Mori Y Yamagishi A 《Dalton transactions (Cambridge, England : 2003)》2012,41(3):747-751
Dinuclear Ru(III) complexes, [Ru(III)(acac)(2)(dabe)Ru(III)(acac)(2)] (acacH = acetylacetone; dabeH(2) = 1, 2-diacetyl-1,2-dibenzoylethane) and [Ru(III)(acac)(2)(tbet)Ru(III)(acac)(2)] (tbetH(2) = 1,1,2,2-tetrabenzoylethane) were synthesized by reacting [Ru(acac)(2)(CH(3)CN)(2)]PF(6) with dabeH(2) and tbetH(2) respectively, in toluene. The X-ray structural analysis of a meso-type dinuclear Ru(III) complex, ΔΛ-[Ru(III)(acac)(2)(dabe)Ru(III)(acac)(2)], showed that the bridging part became chiral due to the orthogonal twisting of two non-symmetrical β-diketonato moieties. To confirm this conclusion, the complex was resolved chromatographically to provide a pair of optical antipodes. Such chirality in the bridging part was not generated for [Ru(III)(acac)(2)(tbet)Ru(III)(acac)(2)], because the β-diketonato moieties in tbet(2-) are symmetrical. 相似文献
17.
The modification of CaCO(3) crystal growth by synthetic L-Ser(PO(3)H(2)) and L-Thr(PO(3)H(2)) containing polypeptides is described. The amino acids Gly, L-Glu, L-Asp, L-Ser, L-Ala, and L-Lys induced rhombohedral calcite with a rough surface. Dipeptides, Xaa-L-Ser(PO(3)H(2)) (Xaa = Gly, L-Glu, L-Asp, L-Ser, L-Ala and L-Lys) induced vaterite crystals in the lower [Ca(2+)]. On the other hand, L-Ser(PO(3)H(2))-containing polypeptides formed spherical vaterite and fibrous calcite. The characteristic helical calcite was found in the presence of copoly[L-Ser(PO(3)H(2))(75)L-Asp(25)] or poly[L-Ser(PO(3)H(2))(3)-L-Asp]. Fibrous calcite, spherical vaterite, and helical calcite crystals were subjected to XRD and EDX analysis. XRD revealed the specific faces of these crystals. EDX spectra and surface analysis visualized the localization of the polypeptides and CaCO(3) components. Together with TEM and SAED data, we propose hypothetical growth mechanisms for the fibrous and helical calcite crystals. 相似文献
18.
Tomoyuki Tajima Yukie Yamaguchi Yo-hei Shiomoto Yutaka Takaguchi 《Phosphorus, sulfur, and silicon and the related elements》2013,188(1):2-11
Abstract We succeeded in the synthesis of a novel poly(amidoamine) dendrimer having diphenyl diselenide at the core. Modification of the dendrimer diselenide by the reaction with glucono-δ-lactone in methanol gave a water-soluble dendrimer diselenide having chiral terminal groups. The structures of dendrimers were satisfactorily confirmed by MAIDI-TOF MS spectrometry, elemental analysis, and NMR spectroscopy. Interestingly, induced circular dichroism (ICD) of the interaction between the diphenyl diselenide core and D-gluconamide periphery of the dendrimer was observed at 300 nm. Supplemental materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements to view the free supplemental file. GRAPHICAL ABSTRACT 相似文献
19.
Akihiko Yukie 《Mathematische Annalen》1992,292(1):355-374
Partially supported by NSF Grant DMS-8803085, DMS-8610730 相似文献
20.
Kakuyanagi K Saitoh M Kumagai K Takashima S Nohara M Takagi H Matsuda Y 《Physical review letters》2005,94(4):047602
We present a 115In NMR study of the quasi-two-dimensional heavy-fermion superconductor CeCoIn5 believed to host a Fulde-Ferrel-Larkin-Ovchinnikov (FFLO) state. In the vicinity of the upper critical field and with a magnetic field applied parallel to the ab plane, the NMR spectrum exhibits a dramatic change below T*(H) which well coincides with the position of reported anomalies in specific heat and ultrasound velocity. We argue that our results provide the first microscopic evidence for the occurrence of a spatially modulated superconducting order parameter expected in a FFLO state. The NMR spectrum also implies an anomalous electronic structure of vortex cores. 相似文献