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Muhammad Ali Khalid Mohammed Khan Uzma Salar Mohammed Ashraf Muhammad Taha Abdul Wadood Sujhla Hamid Muhammad Riaz Basharat Ali Shahbaz Shamim Farman Ali Shahnaz Perveen 《Molecular diversity》2018,22(4):841-861
This study is focused on the identification of thiazole-based inhibitors for the \(\alpha \)-glucosidase enzyme. For that purpose, (E)-2-(2-(arylmethylene)hydrazinyl)-4-arylthiazole derivatives were synthesized in two steps and characterized by various spectroscopic techniques. All derivatives and intermediates were evaluated for their in vitro \(\alpha \)-glucosidase inhibitory activity. Thiosemicarbazones 20 and 35, and cyclized thiazole derivatives 2, 5–11, 13, 15, 21–24, 27–31, and 36–37 showed significant inhibitory potential in the range of \(\hbox {IC}_{50}=6.2\pm 0.19\)–\(43.6\pm 0.23~\upmu \hbox {M}\) as compared to standard acarbose (\(\hbox {IC}_{50}=37.7\pm 0.19~\upmu \hbox {M}\)). A molecular modeling study was carried out to understand the binding interactions of compounds with the active site of enzyme. 相似文献
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Basharat S Carmalt CJ King SJ Peters ES Tocher DA 《Dalton transactions (Cambridge, England : 2003)》2004,(21):3475-3480
The donor-functionalised alkoxides [Et(2)Ga(OR)](2)(R = CH(2)CH(2)NMe(2)(1), CH(CH(2)NMe(2))(2)(2), CH(2)CH(2)OMe (3), CH(CH(3))CH(2)NMe(2)(4), C(CH(3))(2)CH(2)OMe (5)) were synthesised by the 1:1 reaction of Et(3)Ga with ROH in hexane or dichloromethane at room temperature. Reaction of Et(3)Ga with excess ROH in refluxing toluene resulted in the isolation of a 1:1 mixture of [Et(2)Ga(OR)](2) and the ethylgallium bisalkoxide [EtGa(OR)(2)](R = CH(2)CH(2)NMe(2)(6) or CH(CH(3))CH(2)NMe(2)(7)). X-ray crystallography showed that compound 6 is monomeric and this complex represents the first structurally characterised monomeric gallium bisalkoxide. Homoleptic gallium trisalkoxides [Ga(OR)(3)](2) were prepared by the 1:6 reaction of [Ga(NMe(2))(3)](2) with ROH (R = CH(2)CH(2)NMe(2)(8), CH(CH(3))CH(2)NMe(2)(9), C(CH(3))(2)CH(2)OMe (10)). The decomposition of compounds 1, 4, 5 and 8 were studied by thermal gravimetric analysis. Low pressure CVD of 1 and 5 resulted in the formation of thin films of crystalline Ga(2)O(3). 相似文献
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Photon emission originating from sputtering of a polycrystalline aluminum surface under 1–10 keV ion (H+, He+, Ar+, Kr+ and Xe+) bombardment has been studied. Measured photon emission yields from the 3d 2D3/2 resonance transition of sputtered excited Al atoms and calculated nuclear stopping powers are compared. The results demonstrate that elastic collisions play a major role in photon emission. Moreover, measurements of photon intensity as a function of the distance from the target surface show that decays of sputtered excited ions Al+ and Al2+ are faster than decays of excited Al atoms, and less affected by cascade repopulation and de-excitation of fast ions. 相似文献
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Thermal cyclization for a series of substituted vinylheptafulvenes (VHFs) to dihydroazulenes (DHAs) was studied at PBE0 method of density functional theory in the gas phase and in the acetonitrile solvent (through PCM). Judicious control of the thermal reaction through substituent is quite necessary to design thermally robust DHA–VHF photoswitches. For most of the substituents, DHA was predicted thermodynamically stable over VHF except for amino (in gas phase and solvent) and hydroxyl (in acetonitrile), where DHA isomers were calculated thermally unstable compared to VHF. Activation barriers for thermal electrocyclic reaction in both media showed positive correlation with Taft’s σ R values at positions 7 and 5, however, a negative correlation was observed at position 4 and 6. The latter unprecedented behavior is proposed to arise from the delocalization of negative charges on the seven membered ring. Activation barriers for amino-substituted VHFs were generally lower than expected from Taft’s σ R. A fluoro group at the position 7 was quite effective in imparting very high activation barrier (31.73 kcal mol?1) for the thermal cyclization in the gas phase. However, in the acetonitrile solvent, the highest activation barriers were observed for electron withdrawing CHO (28.10 kcal mol?1) and NO2 (28.13 kcal mol?1) groups at positions 7. 相似文献
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Spherulites of holmium tartrate trihydrate and holmium nitro-tartrate monohydrate have been grown in silica gel medium by
making holmium nitrate to react with tartaric acid at high supersaturations. The mechanism of spherulitic growth of holmium
tartrates is discussed. The spherulitic crystallization is shown to be due to heterogeneous nucleation. In the early stages
of growth an amorphous spherical mass gets nucleated inside the gel. Crystal fibers diverge radially from the surface of the
spherical mass giving rise to a spherical polycrystalline holmium tartrate. Thermal stability of the two types of spherulites
grown in the silica gel shows that the holmium tartrate trihydrate is more stable than holmium nitro-tartrate monohydrate.
The surface morphology and internal structure of the spherulites of holmium tartrates have been studied by using scanning
electron microscopy. The results on growth kinetics are given by studying the variation of radius of spherulites as a function
of time. A non-linear time–size relations under several conditions of growth have been observed, which suggests a non-uniform
solute concentration at the crystal surface. 相似文献
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Maria Riffat U. Nisa Muhammad Hanif Adeem Mahmood Khurshid Ayub 《Journal of Physical Organic Chemistry》2014,27(11):860-866
The aromaticities of azines relative to benzene have been estimated by fusion with 15,16‐dimethyldihydropyrene. Chemical shift data for the azine‐fused dihydropyrenes (calculated at GIAO HF/6‐31G*//B3LYP/6‐31 + G*) were used to estimate the reduction in the dihydropyrene nucleus aromaticity. Choice of the saturated reference model was quite crucial in reliable estimation of aromaticity. Reference models with partial unsaturation at azine (21,23,25–32) gave better estimate of aromaticity than the parent dimethyldihydropyrene. Aromaticities of azines through chemical shift data and geometric parameter analysis were found to be 90–100% to that of benzene, highly consistent with the aromaticity estimation by nucleus independent chemical shift(0)πzz calculations. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
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Heat and mass transfer with phase change in a rectangular enclosure packed with unsaturated porous material 总被引:3,自引:0,他引:3
The paper has presented a seven-field mathematical model with ten variables to describe the simultaneous heat and mass transfer with phase change in the unsaturated porous medium that is enclosed in a rectangular enclosure. Both liquid and vapor migration in the porous matrix are evaluated at the same time, and gaseous bulk motion is simulated numerically. The numerical results are discussed with emphasis on the effect of evaporation and condensation of R113 in the vertical enclosure, which may have an application in the room passive heating for the buildings in winter. As solar energy or low-grade waste heat could be used if the enclosure is adequately designed to transfer heat from the outside to the room of the building, the present method may be propitious to the energy conservation. Aimed to this purpose, the heat transfer character of the enclosure is analyzed for the change of Nu number with different Ra number and Da number. 相似文献