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排序方式: 共有128条查询结果,搜索用时 15 毫秒
61.
Radha Krishna Singamsetty Satish Kumar Vujjini Nagaraju Manne Brahmeshwara Rao Mandava Venkata Naga Vurimidi Himabindu Apurba Battacharya 《合成通讯》2013,43(24):4452-4459
A noninfringing synthesis of simvastatin 1, starting from lovastatin 2, is presented. This synthesis features the protection of the free hydroxyl group of the lovastatin with 3,4-dihydro-2H-pyran (DHP) and opening of the lactone ring with n-BuNH2 to afford amide 4 as a key intermediate. 相似文献
62.
2,6-Dichloropurine hydrochloride reacts with various types of alcohols using different alumina catalysts and converts into its N-9-alkyl-2-chloro-6-hydroxy-9H-purine products to an extent of 49–74%. The product selectivity depends on the stability of carbocation generated from the alcohol. More stable carbocation formulates both N-7 and N-9-alkyl-2,6-dichloropurine products, whereas the less stable carbocation results in exclusively N-9-alkyl-2-chloro-6-hydroxy-9H-purine. The catalytic activity of alumina prepared using the sol-gel method has larger Brunauer, Emmett, and Teller (BET) surface area and hence shows significantly greater catalytic activity than the commercially available alumina samples. 相似文献
63.
Ashok D. Nagaraju N. Lakshmi B. Vijaya Sarasija M. 《Russian Journal of General Chemistry》2019,89(9):1905-1910
Russian Journal of General Chemistry - In the present study, we report the synthesis of 5-[4-(3-phenyl-4,5-dihydro-1H-pyrazol-5-yl)phenyl]-1H-tetrazole derivatives by the Michael addition of... 相似文献
64.
Murthy JN Nagaraju M Sastry GM Rao AR Sastry GN 《Journal of computer-aided molecular design》2005,19(12):857-870
Summary This study sheds new light on the role of acidic residues present in the active site cavity of human aromatase. Eight acidic
residues (E129, D222, E245, E302, D309, E379, D380 and D476) lining the cavity are identified and studied using comparative
modeling, docking, molecular dynamics as well as statistical techniques. The structural environment of these acidic residues
is studied to assess the stability of the corresponding carboxylate anions. Results indicate that the environment of the residues
E245, E302 and D222 is most suitable for carboxylate ion formation in the uncomplexed form. However, the stability of D309,
D222 and D476 anions is seen to increase on complexation to steroidal substrates. In particular, the interaction between D309
and T310, which assists proton transfer, is found to be formed following androgen/nor-androgen complexation. The residue D309
is found to be clamped in the presence of substrate which is not observed in the case of the other residues although they
exhibit changes in properties following substrate binding. Information entropic analysis indicates that the residues D309,
D222 and D476 have more conformational flexibility compared to E302 and E245 prior to substrate binding. Interaction similar
to that between D476 and D309, which is expected to assist androgen aromatization, is proposed between E302 and E245. The
inhibition of aromatase activity by 4-hydroxy androstenedione (formestane) is attributed to a critical hydrogen bond formation
between the hydroxy moiety and T310/D309 as well as the large distance from D476. The results corroborate well with earlier
site directed mutagenesis studies. 相似文献
65.
A Convenient and Facile Hantzsch Synthesis of Aryl Imidazo[1,2‐b]Isoxazolyl‐N‐aryl Thiazol Amines 下载免费PDF全文
E. Rajanarendar K. Thirupathaiah S. Ramakrishna D. Nagaraju 《Journal of heterocyclic chemistry》2016,53(6):1983-1989
The Hantzsch synthesis of novel aryl imidazo[1,2‐b]isoxazolyl‐N‐aryl thiazol amines 5 analogues were described. Reaction of 3‐aminoisoxazole 1 with substituted phenacyl bromides 2 in dry ethanol afforded the corresponding 6‐methyl‐3‐arylimidazo[1,2‐b]isoxazoles 3 in good yields. Compounds 3 on reaction with chloroacetyl chloride in 1,4‐dioxane furnished the corresponding 2‐chloro‐1‐(6‐methyl‐3‐arylimidazo[1,2‐b]isoxazol‐2‐yl)ethanones 4 . Compounds 4 on heating with N‐aryl thioureas in an oil bath underwent cyclization to afford the title compounds viz., imidazo[1,2‐b]isoxazolyl‐N‐aryl thiazol amines 5 in moderate to good yields by Hantzsch synthesis. 相似文献
66.
Nagaraju Barsu Md. Atiur Rahman Malay Sen Prof. Basker Sundararaju 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(27):9135-9138
An efficient and external oxidant‐free, Cp*CoIII‐catalyzed C(sp3)?H bond amidation of 8‐methylquinoline, using oxazolone as an efficient amidating agent, is reported for the first time under mild conditions. The reaction is selective and tolerates a variety of functional groups. Based on previous reports and experimental results, the deprotonation pathway proceeds through an external base‐assisted concerted metalation and deprotonation process. 相似文献
67.
Experimental study of dc and ac transport properties of CuInSe2/ZnO heterostructure is presented. The current-voltage (I-V) and frequency dependent capacitance (C-f) characteristics of CuInSe2/ZnO heterostructure were investigated in the temperature range 160-393 K. The heterostructure showed non-ideal behavior of I-V characteristics with an ideality factor of 3.0 at room temperature. Temperature dependent dc conductivity studies exhibited Arrhenius type behavior and revealed the presence of trap level. The C−2-V plot measured at frequency 50 kHz had shown non-linear behavior. An increase in capacitance with temperature was observed. The capacitance-frequency characteristics exhibited a transition between low frequency and the high frequency capacitance. As the temperature was lowered the transition occurred at lower frequencies. The frequency and temperature dependent device capacitance had shown a defect state having activation energy of 108 meV. 相似文献
68.
A capillary electrophoresis (CE) method is described for the simultaneous determination of copper and iron after complexation with a readily biodegradable chelating agent, [S,S']-ethylenediaminedisuccinic acid (EDDS), in wood pulp. CE separation was performed in a fused-silica capillary (50 microm i.d.; total length, 65 cm) with an electrolyte containing 25 mM borate buffer and 0.5 mM CTAB at pH 7.0 and an applied voltage of -25 kV. The samples were introduced by applying a 50 mbar pressure for 2 s, and detection of the complexes was monitored at 245 nm. The methodology performance of the methods was evaluated in terms of the linearity, limit of detection (LOD), limit of quantitation (LOQ) and reproducibility. The applicability of the method was demonstrated for the analysis of copper and iron in wood pulp. 相似文献
69.
CuIn1−xAlxSe2 (CIASe) thin films with x=0.25, 0.5 and 0.65 were prepared by four-source elemental evaporation. The structural and optical properties were investigated by X-ray diffraction, scanning electron microscopy, energy dispersive analysis, and optical transmission. The results showed that these films contain chalcopyrite structure with preferred orientation along (112) direction. The morphology, grain distribution and composition of CIASe films were studied and compared for different Al content. The optical studies revealed that the films were highly absorbing and the energy band gap calculated from transmission spectra for x=0.25, 0.5 and 0.65 were 1.2, 1.51 and 1.73 eV, respectively. The variation of Al content in the CIASe composition offered a very effective change in the optical band gap. 相似文献
70.
Manjunath Krishnappa Dr. Virgínia S. Souza Dr. Nagaraju Ganganagappa Dr. Jackson D. Scholten Prof. Sérgio R. Teixeira Prof. Jairton Dupont Dr. Ramakrishnappa Thippeswamy 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(49):17624-17630
Hydrolysis of TiCl4 in a diether‐functionalized imidazolium ionic liquid (IL), namely 1‐methyl‐3‐[2‐(2‐methoxy(ethoxy)ethyl]imidazolium methane sulfonate (M(MEE)I ? CH3SO3), results in a heterostructured organic/inorganic and sponge‐like porous TiO2 material. The thermal treatment (300 °C) followed by calcination (500 °C) affords highly porous TiO2. The characterization of the obtained samples (with and without IL, before and after calcination) by XRD, SEM, and TEM reveals TiO2 anatase crystalline phases and irregular‐shaped particles with different porous structures. These hierarchical‐structured mesoporous TiO2 nanomaterials were employed as efficient photocatalysts in the water‐splitting process, yielding up to 1304 μmol g?1 on hydrogen production. 相似文献