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71.
A catalyst-free multicomponent reaction (MCR) capable of affording a wide range of novel spiro pyranopyrazole derivatives from pyrazolone in situ formed from acetylenic esters with hydrazine hydrate at room temperature with isatin and malononitrile is reported. A plausible mechanism is suggested. Catalyst-free conditions along with green solvent system make the process ecofriendly as well as economical. Simple reaction conditions and easy work-up procedure that resulted into simple isolation and purification of products by non-chromatographic methods, that is, by simple recrystallization from methanol as well as novelty are the significant advantages of the present protocol. 相似文献
72.
Patil VS Krishna SR Hawaldar RR Gaikwad AB Sathaye SD Patil KR 《Journal of colloid and interface science》2011,358(1):238-244
Nearly monodisperse rhodium nanoparticles with adsorbed NH(x) were synthesized at the CCl(4)-water interface. The presence of NH(x)-adsorbed species was confirmed by energy-dispersive X-ray analysis (EDX) and X-ray photoelectron spectroscopy (XPS) studies. The synthesis of controlled size 2-38 nm rhodium particles was studied as a function of reducing agent concentration by transmission electron microscopy (TEM). HRTEM confirmed the formation of rhodium nanoparticles having fringe spacing consistent with reported Rh (111) planes. The continuity of these films over an area of 1×1 μm was revealed by atomic force microscopy (AFM) studies. The electrocatalytic application of these nanostructure Rh-NH(x) thin films for formaldehyde oxidation in 0.5M NaOH was investigated by cyclic voltammetry. The Rh nanoparticles formed by the present strategy are expected to be useful for other catalytic applications also. 相似文献
73.
74.
Dharker PN Gaikwad SM Suresh CG Dhuna V Khan MI Singh J Kamboj SS 《Journal of fluorescence》2009,19(2):239-248
Transitions in the tryptophan microenvironment and secondary structure of two monocot lectins from Sauromatum guttatum and Arisaema tortuosum under different denaturing conditions were studied by steady state and time resolved fluorescence and CD spectroscopy. The
lectins exist as tetramers with a single tryptophan residue estimated per monomer, present in a polar environment. Quenching
with ionic quenchers showed predominantly electropositive environment for tryptophan residues. Acrylamide had maximum quenching
effect. A decrease in KI quenching due to lectin denaturation indicated redistribution of charges as a result of possible
conformational change. The two values for lifetimes of tryptophanyl population (1.2–1.4 and 6.3–6.4 ns) reduced substantially
on quenching or denaturation. Similarly, both the lectins showed a drastic loss of secondary structure in 5 M Gdn-HCl or 6 M
Urea or at pH 2.0 and below. For the first time araceous lectins, like legume lectins are shown to bind adenine. The presence
of a compact structure at alkaline pH 10.0–12.0 was observed in CD spectra. 相似文献
75.
Mahesh R. Kulkarni Nitin P. Lad Vijay M. Khedkar Nitin D. Gaikwad 《Journal of heterocyclic chemistry》2021,58(6):1359-1370
With the aim of expanding the scope of SAR on piperlongumine (PL), a naturally occurring anticancer molecule, we have designed a novel hybrid molecule bearing 3,4-dihydroisoquinolin-1(2H)-one and trans-cinnamic acids. The structure, based on hybridization strategy, is used for hybridization of naturally occurring scaffolds. We have synthesized 14 hybrid molecules by coupling 3,4-dihydroisoquinolin-1(2H)-one core with cinnamic acids using the mix anhydride approach. The newly synthesized inhibitors were evaluated for cell viability against breast cancer MCF-7 and cervical cancer HeLa cell lines. Furthermore, the active compounds were screened for their potential in breast cancer MDA-MB-231, cervical cancer C33A cell lines, prostate cancer DU-145, PC-3, and normal VERO cells. From the series, compound 10g was seen to inhibit MCF-7 cell growth significantly with GI50 < 0.1 μM along with growth inhibition in MDA-MB-231 (GI50 = 20 μM) and C33A (GI50 = 3.2 μM). While the inhibitor 10i inhibits MCF-7 breast cancer cell growth GI50 = 3.42 μM along with inhibition of cell growth in MDA-MB-231 (GI50 = 30 μM), HeLa (GI50 = 7.67 μM), C33A (GI50 = 13 μM), DU-145 (GI50 = 6.45 μM), PC-3 (GI50 = 8.68 μM), and VERO (GI50 = 2.93 μM), respectively. Furthermore, molecular docking study demonstrated these compounds could bind tightly to the colchicine domain of tubulin through a network of favorable steric and electrostatic interactions and thus act as a tubulin polymerization inhibitor. 相似文献
76.
The double diffusive convection in a horizontal anisotropic porous layer saturated with a Boussinesq binary fluid, which is
heated and salted from below in the presence of Soret and DuFour effects is studied analytically using both linear and non-linear
stability analyses. The linear analysis is based on the usual normal mode technique, while the non-linear analysis is based
on a minimal representation of double Fourier series. The generalized Darcy model including the time derivative term is employed
for the momentum equation. The critical Rayleigh number, wavenumbers for stationary and oscillatory modes, and frequency of
oscillations are obtained analytically using linear theory. The effects of anisotropy parameter, solute Rayleigh number, and
Soret and DuFour parameters on the stationary, oscillatory convection, and heat and mass transfer are shown graphically. Some
known results are recovered as special cases of the present problem. 相似文献
77.
Baburajan A. Gaikwad R. H. Sudheendran V. Shah C. A. Ravi P. M. Karunakara N. 《Journal of Radioanalytical and Nuclear Chemistry》2019,320(1):15-25
Journal of Radioanalytical and Nuclear Chemistry - Tritium concentration in different parts of the rice plants, grown in villages around Tarapur Atomic Power Station, west coast of India, exposed... 相似文献
78.
Xantphos- and dithiolate-ligated macrocyclic palladium complexes as an efficient and stable catalyst for the carbonylative Suzuki–Miyaura cross-coupling reaction have been synthesized. The catalysts were characterized by 1H-nuclear magnetic resonance (NMR), CHNS (carbon, hydrogen, nitrogen, and sulfur) analysis, melting point analysis, and 31P-NMR spectroscopy. Several sensitive functional groups (e.g., –NO2, –F, –Cl, –Br, –NH2, and –CN) on the aromatic ring were well tolerated in the carbonylative Suzuki–Miyaura coupling reaction. The present palladium complexes produce six times higher turnover number (TON) and five times higher turnover frequency (TOF) compared with conventional homogeneous palladium precursors. Maximum TONs in the range of 105 to 106 and TOF in the range of 104 to 105 could be generated by a very low amount of catalyst loading (10–5 mol%). 相似文献
79.
Thionyl chloride-mediated chalcogenation of imidazo[1,5-a]pyridine serves as a new protocol for the synthesis of rare bisimidazopyridyl sulfides. This method provides the new route to synthesis of 2-azaindolizine sulfur-bridged dimers called chalcogenide under metal-free, elemental sulfur-free conditions without the use of polar solvents in regio-selective manner, at room temperature with the simple operational procedure. 相似文献
80.
Dr. Abir Goswami Dr. Sudhakar Gaikwad Prof. Dr. Michael Schmittel 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(9):2997-3001
Enzymes are encoded with a gamut of information to catalyze a highly selective transformation by selecting the proper reactants from an intricate mixture of constituents. Mimicking biological machinery, two switchable catalysts with differently sized cavities and allosteric control are conceived that allow complementary size-selective acyl transfer in an on/off manner by modulating the effective local concentration of the substrates. Selective activation of one of two catalysts in a mixture of reactants of similar reactivity enabled upregulation of the desired product. 相似文献