共查询到20条相似文献,搜索用时 375 毫秒
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A multicomponent reaction that employs an unsaturated carboxylic acid, a 1,2 or 1,3 amino alcohol and gaseous CO and H2 has been discovered. Thus, hydrocarbonylation of the carboxylic acid double bond generates a linear aldehyde, that is, immediately transformed into an oxazolidine. Further microwave assisted intramolecular lactamization delivers oxazolopiperidines with the generation of six new bonds in a one-pot single step. Bicylic, tricyclic, tetracyclic, and spirocyclic oxazolopiperidines can be prepared in good yields and acceptable stereoselection. The reaction did not occur under conventional heating even at higher temperature and pressure and for longer time, showing that microwave heating is indispensable to the process. 相似文献
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A facile, high yielding synthesis of 9,10-dihydro-9,10-ethano- anthracene-11- carboxylic acid methyl ester using a modified commercial domestic microwave oven is reported. 相似文献
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Wen Jian LAO Yu Hua ZHANG Yue Qi LIU Qiang Jin WU Zi Xiang HUANG Qing Yu OU* Lanzhou Institute of Chemical Physics Chinese Academy of Sciences Lanzhou Fujian Institute of Research on the Structure of Matter Chinese Academy of Scie 《中国化学快报》2001,(4)
Carbazole and its derivatives have attracted the attention due to its photophysical and photochemical properties as well as biological activities1. So far considerable amounts of carbazole derivatives were prepared to probe the nature of electronic states. Among these carbazole derivatives, carbazole-9-carboxylic acids were important intermediates because the carboxylic group is an active function group for further transformation into other functions. The molecular packing modes of carboxylic … 相似文献
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Kristin LippurTõnis Tiirik Marina KudrjashovaIvar Järving Margus LoppTõnis Kanger 《Tetrahedron》2012,68(47):9550-9555
The aromatic nucleophilic substitution reaction of 7-chloroquinolone carboxylic acid and its ethyl ester with cyclic amines under microwave irradiation conditions was investigated. 1H NMR spectroscopy was used to monitor the progress of the substitution reaction. The reaction proceeded in high yield with simple cyclic amines and was less efficient for sterically more demanding bimorpholine derivatives. A Pd-catalyzed amination of quinolone carboxylic acid ethyl ester with bimorpholine derivatives provided new C-7 bimorpholino-substituted quinolone derivatives. 相似文献
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Aberg V Norman F Chorell E Westermark A Olofsson A Sauer-Eriksson AE Almqvist F 《Organic & biomolecular chemistry》2005,3(15):2817-2823
A reagent-free microwave-assisted decarboxylation procedure for carboxylic acid functionalized bicyclic 2-pyridones has been developed. This new method, based on microwave heating at 220 degrees C for 600 seconds in N-methyl pyrrolidone (NMP), proved to be practical and very efficient, resulting in decarboxylated 2-pyridones in near-quantitative yields. The decarboxylated products and the intermediate 2-pyridones in the form of carboxylic acid methyl esters and carboxylic acids were screened for their effect on Abeta-peptide aggregation. Two out of the 21 2-pyridones described in this study inhibited amyloid formation of the Alzheimer Abeta(1-40) peptide. The effect was seen even at a 4 : 1 ratio of 2-pyridone and monomeric Abeta-peptide. 相似文献
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Asheesh Kumar Jain Pradeep Kumar Gupta Kumaran Ganesan Ambuja Pande Deepak Pardasani Ramesh Chandra Malhotra 《Journal of heterocyclic chemistry》2005,42(5):985-989
4‐Benzyloxyindole‐2‐carboxylic acid hydrazide reacts with aromatic and heterocyclic aldehydes in alcoholic medium in refluxing conditions to give 4‐benzyloxy‐1H‐indole‐2‐carboxylic acid (arylidene)‐hydrazides, important synthetic intermediates for the synthesis of a newer class of pharmacologically active compounds. We describe here the synthesis of various 4‐benzyloxy‐1H‐indole‐2‐carboxylic acid (arylidene)‐hydrazides by conventional as well as microwave irradiation techniques. The structures of these compounds have been confirmed by spectroscopic techniques (FTIR, NMR and MS). Some of the interesting features of the electron impact mass spectral fragmentation pattern of these compounds are also discussed. 相似文献
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Silica sulfuric acid was found to be an efficient, recoverable, reusable and environment-friendly catalyst for the fast hydrolysis
of various carboxylic acid esters in high conversions and selectivities under microwave irradiation conditions. This protocol
has the advantages of no corrosion, no environmental pollution, high reaction rate, high yield, and simple work-up procedure. 相似文献
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Microwave-assisted synthesis utilizing supported reagents: a rapid and efficient acylation procedure
[reaction: see text] The application of microwave heating to a polymer-assisted solution-phase (PASP) synthesis technique has been utilized to develop a rapid and efficient protocol for the solution-phase synthesis of amides from either amine or carboxylic acid cores. 相似文献
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Mara Tomassetti Michela Fanì Gianluca Bianchini Sandra Giuli Andrea Aramini Sandro Colagioia Giuseppe Nano Samuele Lillini 《Tetrahedron letters》2013
Chiral substituted phenylethyl-1H-tetrazoles were built-up from the corresponding carboxylic acid derivatives by a useful three-step synthesis. The procedure, that preserves the chiral center from racemization, was successfully applied to a selection of several hit compounds by conversion of the carboxylic acid moiety to the nitrile derivatives and subsequent reaction with trimethylstannyl azide, under microwave conditions. A useful application to the corresponding tetrazole analogue has been found also in the conversion of the aminoacidic moiety like (R)-N-Cbz-phenylglycine showing a wide potential synthetic application. 相似文献
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Application of Microwave Heating Technique to Esterification 总被引:1,自引:0,他引:1
Introduction Although the application of microwave technique has been reported as a new type of energy source chemically, it is only in recent years that this technique has been used as the energy source for organic synthesis. In 1986, R. Gedye, et al., published the report of the benzoate synthesis from the respective reactions between benzene carboxylic acid and methanol, propanol or butanol under microwave heating and the catalysis of H_2SO_4. 相似文献
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Lu Ta-Jung 《合成化学》2004,12(Z1)
The use of microwave technology in accelerating organic reactions has received intense attention leading to immense growth recently. Accordingly, we have been interested in improving the efficacy of organic processes by microwave irradiation. Here we report our results on the microwave assisted direct amide formation from carboxylic acid and amine, the hydrolysis of biopolymers, and nucleophilic aromatic substitution reaction. The reactions carried out under microwave irradiation, in general, … 相似文献
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We report a facile and rapid removal of Boc protecting groups using microwave heating in H2O, with deprotection only requiring a free carboxylic acid group in the starting material. Unlike previous approaches, no additional reagents are required. 相似文献
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1,3,4-Oxadiazoles can be rapidly and efficiently synthesized from a variety of carboxylic acids and acid hydrazides in one simple step. The use of commercially available PS-PPh3 resin combined with microwave heating delivered the product 1,3,4-oxadiazoles in high yields and purities. 相似文献
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Ignacio Carrera 《Tetrahedron letters》2009,50(38):5399-504
The oxidative C-C cleavage of α-hydroxy ketones was found to proceed smoothly in solvent-free, silica-supported sodium metaperiodate, under microwave irradiation. This provides a useful and green synthetic procedure to form the corresponding carboxylic acid and aldehyde in good yields, avoiding the solubility problems of the sodium metaperiodate in organic solvents. 相似文献
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Takuji HiroseBenjamin G. Kopek Zhao-Hui WangRitsuko Yusa Bruce W. Baldwin 《Tetrahedron letters》2003,44(9):1831-1833
Using imidazole as promotion agent, primary, secondary and phenolic alcohol compounds were esterified with aliphatic and aromatic carboxylic acid anhydrides. Heating a ternary mixture of alcohol, anhydride and imidazole in an unmodified microwave oven produced esters in low to high yields, depending on the steric bulk of the alcohol. 相似文献
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A convenient, solvent‐free Vilsmeier reagent is experimented under neat condition (both thermal and microwave conditions). An efficient method for the synthesis of various substituted 1H‐pyrazole‐4‐carboxylic acid esters is reported. 相似文献
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用微波法在水滑石上负载K2CO3,作为原油酯化脱酸催化剂。研究了浸渍法、超声波法、微波法和机械混合法四种制备方法,微波处理时间和K2CO3负载量对催化剂性质和活性的影响。结果表明,兼具高的水滑石结晶度,良好的K2CO3分散度和高碱量的催化剂有最佳脱酸活性。微波法在保持K2CO3高分散的同时明显缩短水滑石和K2CO3溶液的接触时间,从而保持水滑石的高结晶度,且有助于K与水滑石产生更多碱性中心,得到的催化剂脱酸活性最高。K2CO3负载量15%,微波处理5min制备的催化剂,在200℃,反应时间2h,催化剂和醇用量分别为原油质量的1%和2%时,对绥中高酸值原油的脱酸率可从水滑石的89.2%提高到97.7%。 相似文献