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1.
Journal of Algebraic Combinatorics - Motivated by the theory of correspondence functors, we introduce the notion of germ in a finite poset, and the notion of germ extension of a poset. We show that... 相似文献
2.
Asymmetric monobenzoylation reactions of cyclic meso-1,3- and 1,4-diols were catalyzed by a phosphinite derivative of quinidine to afford the corresponding monobenzoylated diol with good yield and enantioselectivity. [reaction: see text] 相似文献
3.
Mikio Hori Tadashi Kataoka Hiroshi Shimizu Eiji Imai Yukiharu Matsumoto Iwao Miura 《Tetrahedron letters》1981,22(13):1259-1262
The novel ring transformation reactions were found in the reactions of 1,3,7,9-tetra-alkyl-8,9-dihydroxanthines and acetylenic compounds. The reaction of the dihydroxanthine with DMAD gave a propellane type compound and with methyl propiolate afforded the similar type compound and a pyrimido[4,5-b]diazepine derivative. The mechanism of these reactions was also discussed. 相似文献
4.
Geney R Sun L Pera P Bernacki RJ Xia S Horwitz SB Simmerling CL Ojima I 《Chemistry & biology》2005,12(3):339-348
A new computational docking protocol has been developed and used in combination with conformational information inferred from REDOR-NMR experiments on microtubule bound 2-(p-fluorobenzoyl)paclitaxel to delineate a unique tubulin binding structure of paclitaxel. A conformationally constrained macrocyclic taxoid bearing a linker between the C-14 and C-3'N positions has been designed and synthesized to enforce this "REDOR-taxol" conformation. The novel taxoid SB-T-2053 inhibits the growth of MCF-7 and LCC-6 human breast cancer cells (wild-type and drug resistant) on the same order of magnitude as paclitaxel. Moreover, SB-T-2053 induces in vitro tubulin polymerization at least as well as paclitaxel, which directly validates our drug design process. These results open a new avenue for drug design of next generation taxoids and other microtubule-stabilizing agents based on the refined structural information of drug-tubulin complexes, in accordance with typical enzyme-inhibitor medicinal chemistry precepts. 相似文献
5.
Kaoru Suzuki Iwao Nishiyama Yasushi Ozaki Kozo Kuchitsu 《Chemical physics letters》1978,58(1):145-148
Light emission from Cl(5p) atoms (near 440 nm) produced in the reaction of HCl in a discharged flow of argon was investigated with a flowing-afterglow apparatus. Ionic species, most probably argon ions in metastable states, Ar+M, were found to be responsible for the Cl(5p) production in the dissociative excitation of HCl. 相似文献
6.
Methyl and ethyl 2-quinolylacetate were prepared from quinoline 1-oxide via acetoacetie ester derivatives. Methyl 2-quinolyl, 1-isoquinolyl, 6-methoxy-3-pyridazinyl, 4-pyridyl and 2-methyl-4-pyridylacetate were synthesized from the corresponding heterocyclic N-oxides via β-aminoerotonie ester derivatives. 相似文献
7.
2,3-Dihydroimidazo[1,5-α]pyridin-3-one (IV) was obtained by thermolysis of 2-pyridylacetyl azide (II) which was prepared from 2-pyridylacetohydrazide (I) on treatment with an equivalent mole of nitrous acid. Treatment of I with excess nitrous acid yielded α-oximino-α:-(2-pyridyl)-acetylazide (V). Thermal decomposition of V gave 3-(2-pyridyl)-1,2,4-4H-oxadiazolin-5-one (VII). 2-Cyanopyridine (IX) was obtained from V by the action of alkali. 2,3-Dihydroimidazo-[1,5-α ]pyridin-3-one (IV) was rearranged to VII upon treatment with nitrous acid. J. Chem. Soc., 14, 993 (1977) 相似文献
8.
Zhang GJ Song KS Nakamura Y Ueno T Funatsu T Ohdomari I Kawarada H 《Langmuir : the ACS journal of surfaces and colloids》2006,22(8):3728-3734
We report a novel method of one-step direct amination on polycrystalline diamond to produce functionalized surfaces for DNA micropatterning by photolithography. Polycrystalline diamond was exposed to UV irradiation in ammonia gas to generate amine groups directly. After patterning, optical microscopy confirmed that micropatterns covered with an Au mask were regular in size and shape. The regions outside the micropatterns were passivated with fluorine termination by C3F8 plasma, and the chemical changes on the two different surfaces--the amine groups inside the patterned regions by one-step direct amination and fluorine termination outside the patterned regions--were characterized by spatially resolved X-ray photoelectron spectroscopy (XPS). The patterned areas terminated with active amine groups were then immobilized with probe DNA via a bifunctional molecule. The sequence specificity was conducted by hybridizing fluorescently labeled target DNA to both complementary and noncomplementary probe DNA attached inside the micropatterns. The fluorescence micropatterns observed by epifluorescence microscopy corresponded to those imaged by optical microscopy. DNA hybridization and denaturation experiments on a DNA-modified diamond show that the diamond surfaces reveal superior stability. The influence of a different amination time on fluorescence intensity was compared. Different terminations as passivated layers were investigated, and as a result, fluorine termination points to the greatest signal-to-noise ratio. 相似文献
9.
Ai Ito Takamasa Amaki Ayako Ishii Kazuo Fukuda Ryu Yamasaki Iwao Okamoto 《Tetrahedron letters》2018,59(45):3994-3998
Aromatic amides bearing 2-azulenyl group on the amide nitrogen were synthesized and their structures were investigated. The π-electron density of the N-aryl group was found to influence the cis-trans conformational preferences of these compounds in solution. X-ray crystallography revealed that the plane of the 2-azulenyl ring has a strong tendency to lie coplanar with the amide plane when the azulene group is located on the same side as the amide oxygen atom. 相似文献
10.
Methods to prepare fractions of poly(epsilon-caprolactone) with a narrow molecular mass distribution in large quantities have been examined using high osmotic pressure chromatography under the theta condition. Effects of column dimension and coupling columns in series on the separation resolution were studied. We found that use of a thicker column can improve the resolution if adverse effects of viscous fingering are avoided. We also demonstrated that coupling the columns results in a better separation if the second column does not adsorb high-molecular-mass components purified in the first column. 相似文献