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51.
Tadataka Zaima Yoshiharu Matsunaga Keiryo Mitsuhashi 《Journal of heterocyclic chemistry》1983,20(1):1-4
A novel and convenient synthesis of 1H -pyrrole-2,3,4,5-tetracarboxylates is described. Photocyclization of 1,1′-bis(methoxycarbonyl)divinylamine with acetylenedicarboxylates gave 7-azabicyclo[2.2.1]hept-2-ene-1,2,3,4-tetracarboxylates 2a-i , which on melting split ethylene off to yield 1H-pyrrole-2,3,4,5-tetracarboxylates 3a-i quantitatively. 相似文献
52.
[reaction: see text] A copper fluoride-catalyzed cyanomethylation that can be applied to a wide range of ketones and aldehydes was developed using TMSCH(2)CN as a nucleophile. The reaction was extended to a conceptually more advanced copper alkoxide-catalyzed direct addition of alkylnitriles to aldehydes, which can act as a surrogate direct catalytic aldol reaction of esters. These reactions can be applied to the first catalytic enantioselective cyanomethylation of ketones and direct catalytic enantioselective cyanomethylation of aldehydes. 相似文献
53.
McMillan RA Howard J Zaluzec NJ Kagawa HK Mogul R Li YF Paavola CD Trent JD 《Journal of the American Chemical Society》2005,127(9):2800-2801
Self-assembling biomolecules that form highly ordered structures have attracted interest as potential alternatives to conventional lithographic processes for patterning materials. Here, we introduce a general technique for patterning nanoparticle arrays using two-dimensional crystals of genetically modified hollow protein structures called chaperonins. Constrained chemical synthesis of transition metal nanoparticles is initiated using templates functionalized with polyhistidine sequences. These nanoparticles are ordered into arrays because the template-driven synthesis is constrained by the nanoscale structure of the crystallized protein. We anticipate that this system may be used to pattern different classes of nanoparticles based on the growing library of sequences shown to specifically bind or direct the growth of materials. 相似文献
54.
55.
We have applied cavity ring-down spectroscopy to a kinetic study of the reaction of NO3 with CH2I2 in 25–100 Torr of N2 diluent at 298 K. The rate constant of reaction of NO3 + CH2I2 is determined to be (4.0 ± 1.2) × 10−13 cm3 molecule−1 s−1 in 100 Torr of N2 diluent at 298 K. The rate constant increases with increasing pressure of buffer gas below 100 Torr. The reaction of CH2I2 with NO3 has the potential importance at nighttime in the atmosphere. 相似文献
56.
Harayama T Akiyama T Nakano Y Nishioka H Abe H Takeuchi Y 《Chemical & pharmaceutical bulletin》2002,50(4):519-522
A palladium-assisted coupling reaction of aryl triflate with arene was investigated, and a novel Pd reagent prepared from equimolar Pd(OAc)2, 1,3-Bis[diphenylphosphino]propane (DPPP), and Bu3P was developed. This method is useful for intramolecular biaryl coupling reactions, not only between aryl triflate and arene (triflate-amide), but also between aryl halide and arene (halo-amide). 相似文献
57.
Tomohisa Nagamatsu Yoshiji Hantani Minoru Yamada Kenji Sasaki Hiromi Ohtomo Taiji Nakayama Takashi Hirota 《Journal of heterocyclic chemistry》1993,30(1):193-202
As a series of polyheterocyclic compounds for exploitation as anti-platelet agents, tricyclic heterocyclic compounds, 4-substituted 6,7-dihydro-5H-pyrimido[5,4-d][1]benzazepines 3–6, 9, 12–14 , and 16–26 , having nitrogen, oxygen, or sulfur containing functional groups at the 4-position, were prepared. In addition, tetra-cyclic heterocyclic compounds, 3-methyl-1,2,5,6-tetrahydro-4H-imidazo[1′,2′:1,6]pyrimido[5,4-d][1]benzaze-pinium chloride ( 7 ), 1,2,5,6-tetrahydro-4H-imidazo[1′,2′:1,6]pyrimido[5,4-d][1]benzazepines 10a-e , 2,3,6,7-tetrahydro-1H 5H-pyrimido[1′,2′:1,6]pyrimido[5,4-d][1]benzazepine ( 11 ), and 1,2,5,6-tetrahydro-4H-thiazolo-[3′,2′:1,6]pyrimido[5,4-d][1]benzazepinium chloride ( 15 ) via ring closure of 4-(hydroxyalkylamino)- 6, 9a-e , and 3c , and 4-(2-hydroxyethylthio)-6,7-dihydro-5H-pyrimido[5,4-d][1]benzazepine ( 14 ) with phosphoryl chloride or thionyl chloride, respectively, were also prepared. Their inhibitory activities against collagen-induced aggregation of rabbit blood platelets in vitro were investigated. Among them, compound 5 having a morpholino group at the 4-position on the tricyclic nucleus, which enhanced the activity more than 14-fold as compared with aspirin, was found to have the most satisfactory in inhibitory activity. 相似文献
58.
Hamamoto H Anilkumar G Tohma H Kita Y 《Chemical communications (Cambridge, England)》2002,(5):450-451
A novel and efficient oxidative biaryl coupling reaction of phenol ether derivatives using a combination of hypervalent iodine(III) reagent, phenyliodine(III) bis(trifluoroacetate) (PIFA), and heteropoly acid has been developed. 相似文献
59.
Hayakawa K Ando K Yoshida N Yamamoto A Matsunaga A Nishimura M Kitaoka M Matsui K 《Biomedical chromatography : BMC》2000,14(2):72-76
A high-performance liquid chromatographic method has been developed for the determination of saccharides in sake, an alcoholic beverage brewed from rice. Saccharides in sake were separated on a normal phase (carbamoyl bonded silica) column using a linear gradient elution of water in acetonitrile. Seven saccharides, glucose, maltose, isomaltose, maltotriose, panose, isomaltotriose and ethyl alpha-D-glucoside, were determined by a polarized photometric detector. Unidentified peaks suggesting saccharides with polymerization degrees over 4 were also observed. The proposed method did not require any sample clean-up treatment. As an application, saccharide compositions in various kinds of sake were compared. 相似文献
60.
Four new iridoid glycosides, named L-phenylalaninosecologanin (1), 7-O-(4-beta-D-glucopyranosyloxy-3-methoxybenzoyl)secologanolic acid (2), 6'-O-(7alpha-hydroxyswerosyloxy)loganin (3) and (Z)-aldosecologanin (5), were isolated, together with a known one, newly named (E)-aldosecologanin (4), from the stems and leaves of Lonicera japonica. Their structures were established on the basis of chemical and spectral data. 相似文献