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991.
Jason D. Katz 《Tetrahedron》2004,60(43):9559-9568
A highly functionalized 4,5-dihydropyrrole-2-carboxylate is assembled by alkene-enamide ring-closing metathesis. Subsequent intramolecular azomethine imine dipolar cycloaddition provides a triazacyclopenta[cd]pentalene intermediate of potential use in a total synthesis of palau'amine. 相似文献
992.
Ab initio calculation of the 4-ClC6H4CH2Cl molecule was performed by the restricted Hartree-Fock method in the split valence 6–31 G* basis set with complete optimization of its geometry. Populations of p-orbitals of atoms of this molecule were analyzed.35Cl NQR frequencies and asymmetry parameters of the electric field gradient on35Cl nuclei were estimated on the basis of the populations of valent p-orbitals of CI atoms and their components. Good conformity with the experimental values was obtained when only less diffuse components of p-orbitals were used in calculations of populations.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 4, pp. 823–826, April, 1996. 相似文献
993.
I. I. Ponomarev Yu. Yu. Rybkin E. I. Goryunov P. V. Petrovskii K. A. Lyssenko 《Russian Chemical Bulletin》2004,53(12):2881-2883
The reaction of 4,4-dimethyldiphenyl ether with phosphorus trichloride in the presence of anhydrous aluminum chloride was studied. This reaction affords 2,8-dimethyl-10H-105-phenoxaphosphine 10-oxide as virtually the only product. In air, the latter in an alkaline solution is quantitatively transformed into 10-hydroxy-2,8-dimethyl-10H-105-phenoxaphosphine 10-oxide.__________Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 12, pp. 2762–2765, December, 2004. 相似文献
994.
Summary We have carried out up to 8.0 ns molecular dynamics simulation on the ATP-bound complexes of EGFR and HER-2 (homology model)
receptor kinase domains to explore the possible consequences of amino acid residue changes in or close to the ATP site that
might provide insights for selectivity of these kinases towards ATP site inhibitors. The simulation results show the formation
of a channel under Thr766 following the movement of the side chain of Gln767 away from the hinge in EGFR. In HER-2, a similar
movement of Gln799 occurs, but a simultaneous movement of Arg784 towards the hinge region occurs that tends to close the channel.
The movement of Arg784 in HER-2 appears to result from the absence of an anchoring residue like Asp746 in EGFR, which has
been changed to Gly778 in HER-2. In EGFR, this Arg784 is held away from the hinge region by interaction with Asp746, thereby
leaving the channel open. This might be an important contributory factor to differences in selectivity of the ligands between
the two kinases, probably more so than the conservative change of Cys751 of EGFR to serine in HER-2 at the ATP site. 相似文献
995.
A highly convergent and efficient synthesis of (−)-microcarpalide, a 10-membered lactone displaying remarkable microfilament disrupting activity is described. Ring-closing metathesis and Sharpless asymmetric dihydroxylations are the key steps. Our strategy highlights the application of novel hydroxy lactone precursors for the stereoselective synthesis of (−)-microcarpalide. 相似文献
996.
Introduction 2-Hydroxy-1,4-naphthoquinone (HNQ), existing in natural plants,1,2 is popularly separated and purified as dye or pigment. Recent research results show that, with the function to prevent the formation of protein coenzyme of HIV-I, HNQ can inhibit HIV virus from copying and propagating,3,4 HNQs derivatives and di-chloroallyl lawsone are also the inhibitor for RNA syn-thesis of cancer.5 It is well known that there is a rela-tionship between the side chain attached to HNQ an… 相似文献
997.
ZHANG Bi-Song② 《结构化学》2005,(4)
1 INTRODUCTION Molecular assembly and supramolecular che-mistry are young and rapidly growing subjects andhave attracted great attention. Microporous materialsbuilt up by organic ligands and metal ions have po-tential applications in catalysis, chemical absorption,magnetism and electronic conductivity[1~3]. Multi-dentate organic ligands are good building blocks,such as 1,2,4,5-benzene tetracarboxylic acid (BT-CA), 1,3,5-benzene tricarboxylic acid, terephthalicacid, 1,10-phenanthrol… 相似文献
998.
Differential thermal analysis and thermogravimetry were used to evaluate the effect of some additives, such as CaSO4, CaCl2 and silica fume amorphous silica from ferrosilicon synthesis on the mechanism and kinetics of reactions occurring in fly
ash-Ca(OH)2 system. The accelerating role of these additives was demonstrated from the data relating to Ca(OH)2 consumption in hydrated pastes, determined by TG measurements.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
999.
为寻找新的高活性农药 ,根据生物等排原理 ,设计合成了 10种未见文献报道的N′ 5 ( 1H 1,2 ,3 ,4 四唑基 ) N 芳甲酰基硫脲类化合物 .它们的结构经IR ,1HNMR和元素分析确证 .初步的生物活性测定结果表明 ,部分化合物具有优良的除草活性或植物生长调节活性 . 相似文献
1000.
Synthesis and Crystal Structure of [P(C6H5)4][2,9-{N,N′-(2-NH? (C5H4N))}B10H8] [N(C4H9)4]2[B10H10] reacts with 2-aminopyridine forming a product mixture from which [2,9-{N,N′-(2-NH? (C5H4N))}B10H8]? can be isolated by ion exchange chromatography on diethylaminoethyl(DEAE) cellulose. The crystal structure of [P(C6H5)4][2,9-{N,N′-(2-NH? (C5H4N))}B10H8] (triclinic, space group P1 , a = 10.1103(9), b = 11.5665(9), c = 14.877(2) Å, α = 102.600(8), β = 107.567(8) und γ = 96.487(7)°, Z = 2) reveals the bonding of 2-NH2-(C5H4N) via both N atoms to vicinal B atoms of the two square planes of the B10 cluster (B2? N1 = 1,541(7) und B9? N2 = 1.505(7) Å) forming a five-membered ring. 相似文献