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1.
Solid‐Supported Green Synthesis of Substituted Hydrocinnamic Esters by Focused Microwave Irradiation
An efficient chemoselective hydrogenation protocol for substituted cinnamic esters is developed for the synthesis in quantitative yield of corresponding bioactive dihydrocinnamic esters with solid‐supported palladium chloride/ammonium formate (cat.) in HCOOH/H2O 1 : 2 as a hydrogenating agent under focused‐microwave irradiation for 10 min. 相似文献
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Summary. Salicylanilides were prepared in 70–95% yields in 4–8min from phenyl salicylate or phenyl 4-methoxysalicylate and substituted anilines under microwave irradiation under solvent free conditions.Received October 17, 2002; accepted October 22, 2002
Published online July 3, 2003 相似文献
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A series of novel 2,4‐dithioxo‐6‐aryl‐3‐(1′,3′,4′‐thiadiazolo)‐1,3,5‐triazines have been synthesized from 1,3,4‐thiadiazolo‐thioureas and arylaldehydes using microwave irradiations (MWI) over inorganic solid supports. The yield afforded in microwave reactions was 80% whereas it was 60% in conventional reactions. Solid supported synthesis using microwaves has eliminated the usage of toxic substances and organic solvents except for the limited consumption of methanol and ethanol in pre and post reaction stages. This methodology has been proved an efficient, facile, rapid, and ecofriendly synthetic technology. 相似文献
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Unexpected One‐pot Synthesis of Novel 2‐Aminopyrimidine‐4‐ones under Microwave Irradiation 下载免费PDF全文
One‐pot, three‐component condensation of guanidine, ethylbenzoylacetate and various aromatic aldehydes in the presence of NaHCO3 have been investigated by microwave irradiation. The aromatic aldehydes bearing electron‐withdrawing groups undergo condensation with guanidine and ethylbenzoyl‐acetate to afford ethyl‐2‐amino‐4‐aryl‐1,4‐dihydro‐6‐phenylpyrimidine‐5‐carboxylate derivatives via Biginelli reaction. However, reaction of the aromatic aldehydes having electron‐releasing groups with guanidine and ethylbenzoylacetate did not give the corresponding dihydropyrimidines. Instead, novel 2‐amino‐5‐benzoyl‐5,6‐dihydro‐6‐arylpyrimidine‐4(3H)‐ones were obtained via an unexpected mechanism. 相似文献
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I2‐Catalyzed Divergent Regioselective Addition of Methoxybenzenes with Ethenylbenzenes under Microwave Irradiation 下载免费PDF全文
Nalajala Nageswara Rao Maddi Raghavender Reddy Konakalla Ramakrishna Harshadas Mitaram Meshram 《Helvetica chimica acta》2014,97(5):744-749
A highly efficient synthesis of 1,2,2‐triarylethanones has been developed from simple and commercially available electron‐rich arenes and styrenes (ethenylbenzenes). 相似文献
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Majid M. Heravi Dariush Ajami Bagher Mohajerani Mahmood Tajbakhsh Mitra Ghassemzadeh Kourosh Tabar-Hydar 《Monatshefte für Chemie / Chemical Monthly》2001,132(7):881-883
Summary. A new, efficient, and environmentally benign method for the cleavage of semicarbazones has been achieved by a simple reaction
of semicarbazones with clayfen under microwave irradiation.
Received January 4, 2001. Accepted (revised) March 1, 2001 相似文献
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微波辅助固相有机反应 总被引:5,自引:0,他引:5
固相有机合成是组合化学中构建化合物库的主要工具之一[1,2],但是,由于它是连接在固相载体(如树脂等)上的试剂与溶解在有机溶剂中的试剂之间的反应,因此反应比较缓慢.考虑到微波技术对有机反应的协助作用,我们将微波技术应用到固相有机反应中,对比研究了微波... 相似文献
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Venkateshwarlu Jetti Ramakanth Pagadala Jyotsna S. Meshram Himani N. Chopde Latha Malladi 《Journal of heterocyclic chemistry》2013,50(Z1):E160-E165
In an attempt to synthesize antibacterial agents effective against gram‐positive and gram‐negative bacteria, the efficient synthesis of novel bis‐azetidinones ( 3a–j ) has been established. Thus, cycloaddition reaction of substituted bis‐imines with chloroacetylchloride under microwave irradiation in the presence of zeolite yielded bis‐azetidinones ( 3a–j ). Structures of the synthesized compounds have been elucidated on the basis of their elemental analysis and spectral data (IR, 1H‐NMR, 13C‐NMR, and mass spectra). The synthesized bis‐azetidinones were screened for their antibacterial activity against five microorganisms: Bacillus subtilis, Proteus vulgaris, Staphylococcus aureus, Klebsiella pneumoniae, and Escherichia coli. They were found to exhibit good to moderate antibacterial activity. 相似文献
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《合成通讯》2013,43(11):1861-1866
Abstract The reactivity of gem-dicyano epoxides with various alkenes is studies in solvent free conditions, and in homogeneous solution, under microwave irradiation. Microwave heating of these substrates in solvent, yields carbonyl ylides which give 1-3-dipolar cycloaddition. 相似文献
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微波干法催化醛酮与胺的缩合反应 总被引:2,自引:1,他引:2
利用微波辐射和固体中性Al2 O3 载体催化醛酮与胺的缩合反应的方法合成了十六种亚胺 ,研究了微波功率、作用时间、产物提取方式等因素对反应的影响 ;与无微波作用的一般合成方法相比 ,该法明显地提高反应速度及产率 ;文中用低极性熔点递变物质灌装毛细管的方法观测微波作用下反应温度 ,探讨微波作用化学反应的机理 ,其机理除与微波加热作用有关外还与分子间氢键及分子的缔合性有关。 相似文献
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Mazaahir Kidwai Preeti Misra Bhavesh Dave Kumar R. Bhushan Rajendra K. Saxena Meena Singh 《Monatshefte für Chemie / Chemical Monthly》2000,131(11):1207-1212
Summary. A novel synthesis of 6-fluoro-7-(5-aryl-1,3,4-thiadiazol/oxadiazol-2-yl-sulfanyl)-4-quinolone-3-carboxylic acids from 7-chloro-6-fluoro-4-quinolone-3-carboxylic
acid and 5-substituted 1,3,4-thiadiazoles/oxadiazoles on basic alumina under microwave activation is described. All compounds
were screened for their in vitro antibacterial activity against B. lichenformis, 2689, K. aerogens 2281, S. typhimurium 2501, E. herbicola 2491, and P. vulgaris 2027 and found to possess activities comparable to that of the standard drug norfloxacin.
Received May 2, 2000. Accepted (revised) June 13, 2000 相似文献
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A simple, fast and efficient method for the preparation of several 2‐substituted benzimidazole derivatives is reported. Compounds were synthesized through a rapid one‐pot synthesis via microwave irradiation, starting from aldehydes and o‐phenylenediamine, in the presence of H2O2/HCl system in acetonitrile. The significant features of this method are short reaction times, high yields, easy and quick isolation of the products. 相似文献
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2,5-Disubstituted 1,3,4-oxadiazoles have been synthesized by oxidation of 1-aroyl-2-arylidene hydrazines with potassium permanganate on the surface of a solid mineral support as well as in mixtures of acetone and water under microwave irradiation. 相似文献
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Environmentally Sustainable and Chemo‐selectively Favorable Synthesis of Substituted 2H‐Pyran‐2‐ones in Water under MWI 下载免费PDF全文
In this paper, a novel synthesis of diversely substituted 2H‐pyran‐2‐ones via the tandem reaction of 3‐hydroxyhexa‐4,5‐allenic esters in water under the promotion of MWI has been developed. Compared with those reactions carried out in organic solvents, water mediated synthesis of poly‐substituted 2H‐pyran‐2‐ones is not only environmentally sustainable, but also chemo‐selectively favorable. 相似文献
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Mária Mečiarová Janka Podlesná Štefan Toma 《Monatshefte für Chemie / Chemical Monthly》2004,135(4):419-423
Summary. Nucleophilic aromatic substitution reactions with imidazole of haloarenes having strongly electron-withdrawing groups were studied under ultrasonic and microwave irradiations. The course of the SNAr reactions was found to be strongly dependent on the electron-withdrawing properties of the substituents as well as on the leaving ability of the halogen atom. Microwave irradiation allowed to shorten the reaction time and to increase the yields compared with ultrasonic irradiation. 相似文献
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Rapid synthesis of 1,2,3,4-tetrahydropyrimidin-2-ones (THPO) from aromatic aldehydes, β-ketoester and urea (or thiourea) using zinc sulfamate as the catalyst under microwave irradiation was described here. Compared with the classical Biginelli reaction, this new method consistently has the advantages of good yields (76%-96%), short reaction time (3-15 min), no corrosion to equipments, ease of manipulation, and low cost catalyst. 相似文献