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21.
Konda-Yamada Y Asano K Satou T Monma S Sakayanagi M Satou N Takeda K Harigaya Y 《Chemical & pharmaceutical bulletin》2005,53(5):529-536
Oxopropyl E-(pyrrolidine-2-ylidene)glycinamide (5c) and allyl E-(pyrrolidine-2-ylidene)glycinate (5d) were effectively synthesized from 2,3,5-tri-O-benzyl-4-O-tert-butyldimethylsilyl(TBDMS)-D-arabinal (7) using intramolecular 1,3-dipolar cyclic reaction of azide and olefin as a key reaction. These results proved this cyclic reaction should be applicable for the synthesis of various (pyrrolidine-2-ylidene)glycinate and glycinamide. In addition, the development of a synthetic route for the precursor of an unsaturated cyclic dehydro amino acid involved in azinomycins (carzinophilin) using relating glycinate, methyl E-(pyrrolidine-2-ylidene)glycinate (5a) was described. 相似文献
22.
In the present study, we examined the effects of methotrexate (MTX) on the development of autoimmune kidney disease in three kinds of autoimmune prone mice, NZB/NZW F1 (BWF1) mice, MRL/Mp-lpr/lpr (MRL/lpr) mice and NZW/BXSB F1 (WBF1) mice. The results showed that MTX delayed the appearance of proteinuria and prolonged survival of both BWF1 and MRL/lpr mice and inhibited the elevation of blood urea nitrogen (BUN) levels which accompanies the development of lupus nephritis. However, MTX treatment did not affect these in WBF1 mice. Furthermore, MTX could not suppress immunoglobulin G (IgG) class anti-deoxyribonucleic acid (DNA) and anti-trinitrophenol (TNP) antibody production in any variety of mice. These suggest that the therapeutic effect of MTX on BWF1 and MRL/lpr mice does not result in the suppression of IgG autoantibody production. 相似文献
23.
The reaction of delta-silyl-gamma,delta-epoxypentanenitrile derivatives with a base and an alkylating agent affords delta-siloxy-gamma,delta-unsaturated pentanenitrile derivatives via a tandem process that involves the formation of the cyclopropane derivative by epoxy nitrile cyclization followed by Brook rearrangement and an anion-induced cleavage of the cyclopropane ring. 相似文献
24.
Staphylionosides A-K: megastigmane glucosides from the leaves of Staphylea bumalda DC 总被引:1,自引:0,他引:1
Chemical investigation of leaves of Staphylea bumalda DC., collected in the suburbs of Hiroshima City, afforded 11 new megastigmane glucosides, named staphylionosides A-K (3-13), along with two known megastigmane glucosides (1, 2). The relative structures were elucidated from spectroscopic evidence, and the absolute structures of the aglycones were determined by means of the combination of beta-D-glucosylation-induced shift-trends and the modified Mosher's method. 相似文献
25.
Studies on the constituents of Anaxagorea luzonensis A. GRAY 总被引:2,自引:0,他引:2
Five new xanthones, 1,3,6-trihydroxy-5-methoxy-4-prenylxanthone (1), 1,3,5-trihydroxy-6-methoxy-2-prenylxanthone (2), 1,3,5-trihydroxy-4-(3-hydroxy-3-methylbutyl) xanthone (3), 1,3,6-trihydroxy-4-prenylxanthone (4), 3,6-dihydroxy-1,5-dimethoxyxanthone (5) and one new flavonoid, 3,5,7,4'-tetrahydroxy-2'-methoxyflavone (6) along with seven known xanthones and seven known flavonoids were isolated from the bark of Anaxagorea luzonensis A. GRAY and their chemical structures were determined by means of chemical and spectral studies. Almost all flavonoids and one xanthone (13) showed antioxidant activity. 相似文献
26.
Yoshinori Kadoma Takashi Toida Kenji Takeda Keikichi Uno Yoshio Iwakura 《Journal of polymer science. Part A, Polymer chemistry》1975,13(3):707-716
The polymerization of picryl (PMA), 2,4-dinitrophenyl (2,4-DNMA),2,6-dinitrophenyl (2,6-DNMA), 2-methyl-4,6-dinitrophenyl (MDNMA), and 2,6-dimethylphenyl methacrylates (DMMA) was carried out in benzene at 60°C. PMA, 2,6-DNMA, and MDNMA did not undergo radical homopolymerization, while 2,4-DNMA and DMMA did. The results suggest that the growing radical readily attacks the oxygen atom of the nitro group at the 2 position of the terminal phenyl group due to the steric effect of the substituent at the 6 position, resulting in chain termination. PMA formed a charge-transfer complex with 2-naphthyl methacrylate (NMA). The stoichiometric composition of this complex was shown to be 1:1 molar complex. PMA was readily copolymerized with NMA. The amount of solvent affected the composition of the copolymer obtained at a given same mole fraction in feed. The results suggest that charge-transfer interaction between the ester groups affects the copolymerization mechanism. 相似文献
27.
Fischer indolization of ethyl pyruvate 2-methoxyphenylhydrazone (1) with p-toluene-sulfonic acid in benzene in the presence of an enolizable dicarbonyl or an indolic compound gave either an indole product having an active methine group at C6 or a novel type of 3,6′-biindole compound. Structures of the products were established by NMR spectra and chemical evidence. 相似文献
28.
Kunihisa Yoshida Yoshimasa Toyo-Oka Kazusada Takeda 《Journal of heterocyclic chemistry》1995,32(2):701-702
The electrooxidation of 1-methylpyrazole in methanol containing sodium cyanide produced 1-methyl-pyrazole-4-carbonitrile 2 and ?5-carbonitrile 3 in yields of 23 and 8%, respectively (2e-oxidation products), together with 4-methoxy-1-methylpyrazole-5-carbonitrile 4 (4e-oxidation product, 4%). 相似文献
29.
Sasaki M Kawanishi E Nakai Y Matsumoto T Yamaguchi K Takeda K 《The Journal of organic chemistry》2003,68(24):9330-9339
Metalated O-silyl cyanohydrins of beta-silyl-alpha,beta-epoxyaldehyde have been found to serve as functionalized homoenolate equivalents by a tandem sequence involving base-promoted ring opening of the epoxide, Brook rearrangement, and alkylation of the resulting allylic anion. On the basis of mechanistic studies involving competitive experiments using the diastereomeric cyanohydrins, we propose a reaction pathway involving a silicate intermediate 36 formed by a concerted process via an anti-opening of the epoxide followed by the formation of an O-Si bond. 相似文献
30.
M. Saeki M. Nakada T. Kawasaki T. Nishimura T. Kitazawa M. Takeda 《Journal of Radioanalytical and Nuclear Chemistry》2006,270(2):379-384
Summary The correlations of isomer shifts in various neptunyl(V and VI) compounds with crystallographic structures were revaluated.
A linear correlation between the isomer shifts of neptunyl(VI) compounds and Np-O bond lengths of neptunyl group has been
demonstrated. On the other hand, it has been evidenced that the isomer shifts of neptunyl(V) compounds are correlated much
stronger with the mean Np-O distances in the crystals than the lengths in neptunyl(V) group. 相似文献