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61.
Recent advances in the synthesis of C-5-substituted analogs of 3,4-dihydropyrimidin-2-ones: A review
3,4-Dihydropyrimidin-2-ones act as a versatile scaffold in organic synthesis, which serves as a significant template for the development of various therapeutic agents and shows a wide spectrum of activities. The attractive application of 3,4-dihydropyrimidin-2-ones in organic synthesis is undoubtedly owing to C-5 ester group, which is responsible for the change in its bioactivity. Introduction of various groups like electron-withdrawing and electron-donating groups at positions 1, 2, 3, 5, and 6 greatly increased biological activity. Significant efforts have been undertaken to exploit different synthetic routes to synthesize various derivatives of 3,4-dihydropyrimidin-2-ones. This review article gives a comprehensive account of the synthetic utility of C-5 substitution of 3,4-dihydropyrimidin-2-ones used in the design and synthesis of different types of compounds with greater emphasis on recent literature. 相似文献
62.
Electronic structure of the interface between a bathocuproine (BCP) molecule and metal surface was studied by density functional theory. The bond energy of BCP with metal surface increased with decreasing work function of metals, that is, Au, Ag, Al, Mg, and Ca in this order. The charge transfer also increased with decreasing metal work function. It was analyzed that the Fermi level and the lowest unoccupied molecular orbital of BCP are composed of both BCP and metal orbital component, and electron transport properties across the BCP and metal is discussed based on these analyses. 相似文献
63.
Adusumilli Srikrishna Vijendra H. Pardeshi Konda Mahesh 《Tetrahedron: Asymmetry》2010,21(20):2512-2516
The enantiospecific total synthesis of two epimers of the sesquiterpene isocalamusenone has been accomplished starting from the readily available monoterpene (R)-limonene, which of the natural product established the stereostructure and the absolute configuration. 相似文献
64.
A liquid sloshing absorber consists of a container, partially filled with liquid. The absorber is attached to the structure to be controlled, and relies on the structure’s motion to excite the liquid. Consequently, a sloshing wave is produced at the liquid free surface within the absorber, possessing energy dissipative qualities. The behaviour of liquid sloshing absorbers has been well documented, although their use in structural control applications has attracted considerably less attention. 相似文献
65.
Bianchi Type-IX viscous fluid cosmological model is investigated. To get a deterministic model, we have assumed the conditiona = b
m(m is a constant) between metric potentials andη ∞θ whereη is the coefficient of shear viscosity andθ the scalar of expansion in the model. The coefficient of bulk viscosity (ς) is taken as constant. The physical and geometrical
aspects of the model are also discussed. 相似文献
66.
Mahesh Kumar Yadav Anju Rai Anirudh Pradhan 《International Journal of Theoretical Physics》2007,46(11):2677-2687
We investigate the integrability of cosmic strings in Bianchi III space-time in presence of a bulk viscous fluid by applying
a new technique. The behavior of the model is reduced to the solution of a single second order nonlinear differential equation.
We show that this equation admits an infinite family of solutions. Some physical consequences from these results are also
discussed. 相似文献
67.
Vignesh Nayak Mannekote Shivanna Jyothi Prof. R Geetha Balakrishna Dr. Mahesh Padaki Prof. Ahmad Fauzi Ismail 《ChemistryOpen》2015,4(3):278-287
Herein we present a new approach for the complete removal of CrVI species, through reduction of CrVI to CrIII, followed by adsorption of CrIII. Reduction of chromium from water is an important challenge, as CrIV is one of the most toxic substances emitted from industrial processes. Chitosan (CS) thin films were developed on plain polysulfone (PSf) and PSf/TiO2 membrane substrates by a temperature-induced technique using polyvinyl alcohol as a binder. Structure property elucidation was carried out by X-ray diffraction, microscopy, spectroscopy, contact angle measurement, and water uptake studies. The increase in hydrophilicity followed the order: PSf < PSf/TiO2 < PSf/TiO2/CS membranes. Use of this thin-film composite membrane for chromium removal was investigated with regards to the effects of light and pH. The observations reveal 100 % reduction of CrVI to CrIII through electrons and protons donated from OH and NH2 groups of the CS layer; the reduced CrIII species are adsorbed onto the CS layer via complexation to give chromium-free water. 相似文献
68.
Prof. Paulo R. Souza Mendes Mahesh Padmanabhan L. E. Scriven Christopher W. Macosko 《Rheologica Acta》1995,34(2):209-214
A new class of inelastic constitutive equations is presented and discussed. In addition to the rate-of-strain tensor, the stress is assumed to depend also on the relative-rate-of-rotation tensor, a frame-indifferent quantity that brings information about the nature of the flow. The material functions predicted by these constitutive equations are given for simple shear and uniaxial extension. A special case of these equations takes the Newtonian form, except that the viscosity is a function of the invariants of both kinematic tensors on which the stress depends. This simple constitutive equation has potential applications in liquid flow process simulations, since it combines simplicity with the capability of responding independently to shear and extension, as real liquids seem to do. Finally, possible forms for the new viscosity function are discussed. 相似文献
69.
Hu M Li L Wu H Su Y Yang PY Uttamchandani M Xu QH Yao SQ 《Journal of the American Chemical Society》2011,133(31):12009-12020
Fluorescence imaging provides an indispensable way to locate and monitor biological targets within complex and dynamic intracellular environments. Of the various imaging agents currently available, small molecule-based probes provide a powerful tool for live cell imaging, primarily due to their desirable properties, including cell permeability (as a result of their smaller sizes), chemical tractability (e.g., different molecular structures/designs can be installed), and amenability to imaging a wide variety of biological events. With a few exceptions, most existing small molecule probes are however not suitable for in vivo bioimaging experiments in which high-resolution studies of enzyme activity and localization are necessary. In this article, we reported a new class of fluorescently Quenched Activity-Based Probes (qABPs) which are highly modular, and can sensitively image (through multiple enzyme turnovers leading to fluorescence signal amplification) different types of enzyme activities in live mammalian cells with good spatial and temporal resolution. We have also incorporated two-photon dyes into our modular probe design, enabling for the first time activity-based, fluorogenic two-photon imaging of enzyme activities. This, hence, expands the repertoire of 'smart', responsive probes currently available for live cell bioimaging experiments. 相似文献
70.
Sundararajan M Assary RS Hillier IH Vaughan DJ 《Dalton transactions (Cambridge, England : 2003)》2011,40(42):11156-11163
The fate of actinyl species in the environment is closely linked to oxidation state, since the reduction of An(VI) to An(IV) greatly decreases their mobility due to the precipitation of the relatively insoluble An(IV) species. Here we study the mechanism of the reduction of [AnO(2)](2+) (An = U, Np, Pu) both in aqueous solution and by Fe(II) containing proteins and mineral surfaces, using density functional theory calculations. We find a disproportionation mechanism involving a An(V)-An(V) cation-cation complex, and we have investigated how these complexes are formed in the different environments. We find that the behaviour of U and Pu complexes are similar, but the reduction of Np(V) to Np(IV) would seems to be more difficult, in line with the experimental finding that Np(V) is generally more stable than U(V) or Pu(V). Although the models we have used are somewhat idealised, our calculations suggest that there are strong similarities between the biotic and abiotic reduction pathways. 相似文献