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排序方式: 共有73条查询结果,搜索用时 342 毫秒
1.
Kalagouda?B.?GudasiEmail author Ramesh?S.?Vadavi Rashmi?V.?Shenoy Manjula?S.?Patil Siddappa?A.?Patil Munirathinam?Nethaji 《Transition Metal Chemistry》2005,30(6):661-668
The synthesis of cobalt(II), nickel(II) and zinc(II) complexes of 2-pyridine-2-yl-3(pyridine-2-carboxylideneamino)-1,2-dihydroquinazolin-4(3H)-one is described. The ligand and metal complexes were characterized by elemental analysis, conductivity measurements, spectral (u.v.–vis., i.r., 1D n.m.r., 2D hetcor and mass) and thermal studies. The cobalt(II) complex crystallizes as pink crystals in the monoclinic crystal system, space group P21/n with a = 10.066(6) Å, b = 15.929(9) Å, c = 12.624(7) Å, α = 90.00(9)°, β = 110.850 (8)°, γ = 90.00, V = 1891.5 (18) Å3 and Z = 4. The geometry around the cobalt atom is distorted trigonal bipyramidal with τ = 0.83 [structural parameter, τ = (β − α)/60; where α and β are the two basal angles in a five coordinate complex]. 相似文献
2.
V. K. Ahluwalia K. Bhat Chandra Prakash Manjula Khanna 《Monatshefte für Chemie / Chemical Monthly》1981,112(1):119-124
A convenient synthesis of linear pyranocoumarins, viz., 8,8-dimethyl-2H,8H-benzo[1,2-b; 5,4-b]dipyran-2-one (xanthyletin,1) and 8,8-dimethyl-3-phenyl-2H,8H-benzo[1,2-b; 5,4-b]dipyran-2-one (3-phenylxanthyletin,2) is described. The key steps are blocking the 8-position of appropriate 7-hydroxy-2H-1-benzopyran-2-one derivatives with iodine and 1,1-dimethyl-2-propynylation followed by cyclisation.
Ein einfacher Syntheseweg zu linearen Pyranocumarinen. Xanthyletin und 3-Phenylxanthyletin
Zusammenfassung Es wird ein vorteilhafter Weg zur Synthese von linearen Pyranocumarinen am Beispiel von Xanthyletin und 3-Phenylxanthyletin gezeigt. Das Syntheseprinzip besteht in einer Blockierung der 8-Position des entsprechenden 7-Hydroxy-2H-1-benzopyran-2-ons mit Jod und einer 1,1-Dimethyl-2-propinylierung mit nachfolgender Cyclisierung.相似文献
3.
An efficient Pd‐catalyzed method for C—O cross‐coupling of ketoximes and chalcone oximes with activated aryl bromides and bromo‐chalcones has been developed. All oxime ethers were obtained in good to excellent yields by [(π‐allyl)PdCl]2/tBuXPhos ( L7 ) catalyst system. TrixiePhos ( L11 ) was also found to be effective for the oxime coupling. This method offers an easy and smooth coupling of chalcone oximes with activated aryl bromides and bromo‐chalcones, which has not been previously explored. 相似文献
4.
5.
Vinod K. Ahluwalia Manjula Khanna Rishi P. Singh 《Monatshefte für Chemie / Chemical Monthly》1983,114(1):71-77
Condensation of orcinol with 2-methylbuta-1,3-diene (isoprene) has been achieved in the presence of orthophosphoric acid as catalyst leading to the exclusive formation of 2,2-dimethylchromans in one step. A novel route for the synthesis of 5-methylxanthyletin derivatives is described. 相似文献
6.
Manjula Spah Dal Chand Spah Sooyoung Jun Seungmoon Lee Ho-Jun Song Koh Won-Gun Jin-Won Park 《Fluid Phase Equilibria》2009
The EMF data of different metal chlorides (2:1 electrolytes) were obtained by using a cell [MX Hg|MCl2 (m)|AgCl–Ag] at two temperatures. Stock solutions of metal chlorides (CoCl2, CuCl2 and ZnCl2) were prepared by weight in 1,4-dioxane–aqueous mixtures. There was a significant change in the EMF values with change of metal chloride, its concentration and solvents composition. The standard electrode potential (E°) values of the above cell were calculated from the measured EMF of these mixtures. The standard thermodynamic functions (ΔG°, ΔH° and ΔS°) and respective transfer parameters of MCl2 from water to 20, 45 and 70% dioxane–water mixtures were also evaluated. Equilibrium dissociation constants (K1 and K2) as well as the degrees of dissociation (α1 and α2) were obtained by iterative procedures. The data were analyzed in terms of solute–solvent interactions depending on standard and transfer thermodynamic parameters and mean activity coefficients (γ±) of electrolytes. 相似文献
7.
K. A. V. David S. S. Rane Manjula Mathur S. K. Bhattacharjee 《Photochemistry and photobiology》1988,47(1):107-113
Abstract— The role of the replicative state of DNA and of the photosynthetic electron transport system in determining UV-sensitivity of A. nidulans under conditions of non-photoreactivation (by incubating the cells for 24 h in the dark following UV-irradiation) has been investigated. Both the DNA synthesis data and the data on survival levels during cell cycle synchrony forced by light to dark and dark to light transitions showed that the differential UV-sensitivity was not correlated with the replicative state of the DNA as suggested earlier. However, incubation in the light with the herbicides 2/3-4, dichlorophenyl/-l, 1-dimethyl urea (DCMU) and 2-chloro-4-ethylamino-6-isopropylamino-s-triazine (atrazine) which are known to inhibit electron transport by specifically binding to the high turnover B protein of photosynthetic electron transport system II (PSII), enhanced the UV-resistance with kinetics similar to those of a culture transferred from light to dark. We interpret this result as implicative of PSII as the second lethal target in the case of cyanobacteria. The inactivation of electron transport activity of PSII as measured by the fall in DCMU-sensitive fluorescence yield during post-UV dark incubation supports this hypothesis. It is proposed that in wild type cells the survival under conditions of non-photoreactivation following UV-irradiation is essentially determined by the level of dark-repair of damage to PSII and that the 32 kD B protein may have a role in dark-repair of damage to the electron transport system. This hypothesis explains the paradox of negative liquid holding recovery phenomenon under conditions which promote excision-repair of damaged DNA in cyanobacteria. 相似文献
8.
Gregory Fridman Marie Peddinghaus Manjula Balasubramanian Halim Ayan Alexander Fridman Alexander Gutsol Ari Brooks 《Plasma Chemistry and Plasma Processing》2006,26(4):425-442
Thermal plasma discharges have been widely used in the past for treatment of living human and animal tissue. However, extensive thermal damage and tissue desiccation occurs due to extreme temperatures. Some solutions have been offered where the temperature is lowered by short current pulses, addition of noble gases, or significant decrease in the size of treatment electrodes. We propose a method of direct treatment of living tissue that occurs at room temperature and pressure without visible or microscopic tissue damage. The presented Floating-Electrode Dielectric Barrier Discharge plasma is proven electrically safe to human subjects and our results show no gross (visual) or histological (microscopic) damage to skin samples in minutes, complete tissue sterilization from skin flora in seconds, and blood clot formation in seconds of electric plasma treatment. We also observe significant hastening of blood clot formation via electric plasma induced catalysis of “natural” processes occurring in human blood. A model describing these processes is offered.An erratum to this article can be found at 相似文献
9.
Manoj Kumar Yadav Akhilendra Kumar Maurya Gunjan Rajput Krishna Kumar Manar Manjula Vinayak Michael G. B. Drew 《Journal of Coordination Chemistry》2017,70(18):3171-3185
New homoleptic zinc(II) complexes, [Zn(L)2], where L = methyl-3-hydroxy-(3-pyridyl)-2-propenedithioate L1 1, and methyl-3-hydroxy-(4-pyridyl)-2-propenedithioate L2 2, have been synthesized and characterized by elemental (C, H, and N) analysis, ESI-MS, and (IR, UV–vis, NMR) spectroscopy; the structure of 1 has been deduced by X-ray crystallography. The DNA binding and cleavage activity of the complexes have been studied. The cleavage potential of pBR322 DNA by 1 and 2 has been checked. Complex 1, which contains nitrogen of the pyridine group in the 3-position enhances DNA cleavage potential in the presence of ascorbic acid; however, the complex is protective against DNA cleavage in the presence of DMSO or H2O2. Also, 1 causes cytotoxicity against the MCF-7 breast cancer cell line. The efficient cytotoxic activity and DNA cleavage ability of 1 in the presence of ascorbic acid shows its potential anticancer properties and the need for further investigations of its potential as an anticancer drug. 相似文献
10.
Interaction of cobalt cysteinylglycine with histidylserine and histidylphenylalanine was investigated in a 1 : 1 : 1 ratio
at 35°C and 0·10 mol dm−3 ionic strength. Their stabilities and geometries were determined. Their DNA binding and cleavage properties were investigated.
The intrinsic binding constants (K
b
) for DNA bound 1 and 2 (3·03 × 103 M−1 for 1 and 3·87 × 103 M−1 for 2) were determined. Even though the negative charge on the complexes reduced their affinity for DNA, there was an enhancement
of binding through specificity. The degradation of plasmid DNA was achieved by cobalt dipeptide complexes [CoII(CysGly)(HisSer)] (1) and [CoII(CysGly)(HisPhe)] (2). Cleavage experiments revealed that 1 and 2 cleave supercoiled DNA (form I) to nicked circular (form II) through hydrolytic pathway at physiological pH. The DNA hydrolytic cleavage rate constants for complexes 1 and 2 were determined to be 0·62 h−1, for 1 and 0·38 h−1 for 2 respectively. 相似文献