排序方式: 共有15条查询结果,搜索用时 31 毫秒
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Ramesh Ambatwar Sumit Kumar Dhairiya Agarwal Lokesh Chandrakar Gopal L. Khatik 《Journal of heterocyclic chemistry》2024,61(1):163-177
A cobalt(II) perchlorate hexahydrate coordinated synthesis of dihydropyrimidin-ones and -thiones through sonochemistry is developed. Herein, the reaction was demonstrated as a simple, efficient, and one-pot method for synthesizing a series of interesting 3,4-dihydropyrimidin-2(1H)-ones. Further, the reaction mechanism was investigated using mass spectrometry and density functional theory calculations suggesting that a Lewis acid character of cobalt(II) perchlorate hexahydrate plays a crucial role in coordinating carbonyl functionalities and stabilizing the polar intermediates like imine–enamine which further led to cyclized dihydropyrimidin-ones and -thiones. This methodology was further explored to synthesize a gram-scale synthesis of monastrol drug, a kinase inhibitor. 相似文献
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Varun Kumar Anang Pal Gopal L. Khatik Suman Bhattacharya Vipin A. Nair 《Tetrahedron: Asymmetry》2012,23(6-7):434-442
Stereoselective alkylation reactions of 3-aryl-1-alkyl-2-thioxotetrahydropyrimidin-4(1H)-one derivatives were studied. The reaction conditions were optimized to obtain the monobenzylated adduct with improved diastereoselectivity by regulating the reaction kinetics using HMPA as the additive and chiral ethyl lactate as the quencher. The absolute configuration of the product was established by NMR experiments, computational calculations, and single crystal X-ray analysis. 相似文献
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A Gurtu P K Malhotra I S Mittra P M Sood SC Gupta VK Gupta GL Kaul LK Mangotra Y Prakash NK Rao ML Sharma 《Pramana》1974,3(5):311-322
This is a continuation of our earlier investigation (Gurtuet al 1974Phys. Lett. 50 B 391) on multiparticle production in proton-nucleus collisions based on an exposure of emulsion stack to 200 GeV/c beam at the NAL. It is found that the ratioR em = 〈n s〉/〈n ch〉, where 〈n ch〉 is the charged particle multiplicity in pp-collisions, increases slowly from about 1 at 10 GeV/c to 1·6 at 68 GeV/c and attains a constant value of 1·71 ± 0·04 in the region 200 to 8000 GeV/c. Furthermore,R em = 1·71 implies an effectiveA-dependence ofR A =A 0.18,i.e., a very weak dependence. Predictions ofR em on various models are discussed and compared with the emulsion data. Data seem to favour models of hadron-nucleon collisions in which production of particles takes place through adouble step mechanism,e.g., diffractive excitation, hydrodynamical and energy flux cascade as opposed to models which envisage instantaneous production. 相似文献
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The synthesis and stereochemical aspects of the aldol products, 5-methyl-3-(substituted phenyl)-5-[(substituted phenyl) hydroxy methyl]-2-thiooxazolidin-4-ones, are discussed. 相似文献
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An efficient one-pot synthetic strategy for 2-aminobenzoxazoles was developed from isothiocyanates and 2-aminophenol using triflic acid as a cyclodesulfurizing reagent.
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An imidazolidin-2-one chiral auxiliary mediated acetate aldol reaction was explored in the enantioselective synthesis of (S)-dapoxetine (SSRI). The diastereoselective aldol adduct was transformed to highly enantiopure (S)-dapoxetine with overall good yield. 相似文献
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The effects of substituent type and position on the proton transfer reaction of 3-hydroxytropolone(3-OHTRN) have been investigated theoretically by using density functional theory at the level of B3LYP/ 6-31+G** method. The influence of solvent on the proton transfer reactions of substituted 3-OHTRN has been examined using the self-consistent isodensity polarized continuum model(SCI-PCM) in water. As a result, while the proton transfer reaction is kinetically the easiest by substitution on position 3 of-NH2 group in the gas phase, it is kinetically the easiest by substitution on position 5 of the same group in water. In addition, these reactions are either kinetically or thermodynamically easier in the gas phase than that in water, except the reaction of structure with-NH2 group at position 6. 相似文献