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321.
An equation of state based on the Weeks-Chandler-Andersen (WCA) perturbation theory utilizing the simplified random-phase approximation (RPA) term is p of state is applied successfully to calculate the P-V-T relationship for a spherical molecule, argon.For nonspherical molecules, the effects of anisotropic interactions are treated empirically. The calculated P-V-T relationships and saturated properties for nonspherical and nonpolar molecules agree well with experimental data. The potential parameters for nonpolar substances are well correlated with the acentric factors. 相似文献
322.
Chuzo Iwata Yoshiji Takemoto Ayatsugu Nakamura Takeshi Imanishi 《Tetrahedron letters》1985,26(27):3227-3230
The present work deals with a novel method for the introduction of hydroxyl group to the α′-carbon of α,β-unsaturated ketones using triphenyl phosphite ozonide. 相似文献
323.
A novel method for producing optically active pyridyl alcohols 1a-f from the corresponding racemates was developed. When racemic 3-pyridylphenylmethanol 1b is reacted with Catharanthus roseus cell cultures, (−)-1b is obtained in 96% yield with 100 %ee. 相似文献
324.
V. T. Kagiya und K. Takemoto 《Colloid and polymer science》1978,256(6):623
Ohne Zusammenfassung 相似文献
325.
Whereas treatment of the allylic mesylates of N-protected 2-alkyl-4-amino-(E)-2-alken-1-ols with sodium hydride in DMF yields exclusively the corresponding thermodynamically less stable 2,3-trans-2-alkenyl-3-alkylaziridines, exposure of the methyl carbonates of N-protected 2-alkyl-4-amino-(E)-2-alken-1-ols to a catalytic amount of Pd(PPh(3))(4) in THF or 1,4-dioxane affords predominantly the corresponding thermodynamically more stable 2,3-cis-2-alkenyl-3-alkylaziridines. The kinetically favored trans-selective aziridination would be attributed to the allylic 1,3-strain in aza-anionic intermediates. The conformational analysis of the sterically highly congested 2-alkenylaziridines thus obtained is also presented. 相似文献
326.
Yanada R Koh Y Nishimori N Matsumura A Obika S Mitsuya H Fujii N Takemoto Y 《The Journal of organic chemistry》2004,69(7):2417-2422
Novel indium-mediated radical cyclization reactions of aliphatic iodoalkynes have been studied. Treatment of iodoalkynes with a catalytic amount of In (0.1 equiv) and I(2) (0.05 equiv) promotes atom-transfer 5-exo cyclization to give five-membered alkenyl iodides. In contrast, reaction with In (2 equiv) and I(2) (1 equiv) yields reductive 5-exo cyclization products via the same 5-exo cyclization. Both processes are most likely initiated by low-valent indium species. To demonstrate versatility of these reactions, optically active HIV protease inhibitors were synthesized by this reductive cyclization method. Among them, several products, which contain a hydroxyethylamine dipeptide isostere as a transition state-mimicking substructure, proved to possess potent activity (IC(50) = 5-39 nM) against a wide spectrum of HIV strains, including multidrug-resistant variants. 相似文献
327.
The viability of the iridium complex of pybox as chiral catalyst in allylic substitutions and the enantioselective synthesis of branched products was studied. Among several chiral ligands evaluated, the iridium complex of pybox having a phenyl group catalyzed the reaction with high activity to form the branched amines with good enantioselectivities when hydroxylamine, amine, and aniline were employed as a nucleophile. The allylic substitution with oximes proceeded smoothly to give the branched oxime ethers with good enantioselectivities. [reaction: see text] 相似文献
328.
Doubly bridged dicobalt complexes with bidentate diamine ligands were synthesized and characterized by X-ray diffraction studies. Reversible formation and decomposition of the doubly bridged structure utilizing the redox couple between Co(II) and Co(III) were investigated by cyclic voltammetry and UV-vis. 相似文献
329.
Agner G Kaulin YA Gurnev PA Szabo Z Schagina LV Takemoto JY Blasko K 《Bioelectrochemistry (Amsterdam, Netherlands)》2000,52(2):161-167
The pore-forming activities of cyclic lipodepsipeptides (CLPs), syringopeptin 22A (SP22A) and syringomycin E (SRE) were compared on the human red blood cell (RBC) membrane and on bilayer lipid membranes (BLMs). SP22A above a concentration of 4 x 10(5) molecules/cell significantly increased the RBC membrane permeability for 86Rb. With electric current measurements on BLM, it was proved that like SRE, the SP22A formed two types of ion channels in the membrane, small and large, the latter having six times larger conductance and longer dwell time. Both CLPs formed clusters consisting of six small channels, and the channel-forming activity of SP22A is about one order of magnitude higher than that of SRE. A Hill coefficient of 2-3 estimated from the concentration dependence of these CLPs-induced lysis gave a proof of the pore oligomerization on RBCs. Transport kinetic data also confirmed that SP22A pores were oligomers of at least three monomers. While SRE pores were inactivated in time, no pore inactivation was observed with SP22A. The 86Rb efflux through SP22A-treated RBCs approached the tracer equilibrium distribution with a constant rate; a constant integral current was measured on the BLM for as long as 2.5 h as well. The partition coefficient (Kp = 2 x 10(4) l/mol) between the RBC membrane and the extracellular space was estimated for SRE to be at least six times higher than that for SP22A. This finding suggested that the higher ion permeability of the SP22A-treated cells compared to that of SRE was the result of the higher pore-forming activity of SP22A. 相似文献
330.