共查询到20条相似文献,搜索用时 15 毫秒
1.
《Tetrahedron letters》2019,60(39):151084
An effective process for the conversion of carboxylic acid to ketone has been discovered. In this process, carboxylic acid has been activated using p-toluene sulphonyl group. Under the optimized condition, aromatic, aliphatic heteroaromatic carboxylic acids have been proved to be good substrates for this methodology. The byproduct of this reaction can be removed very easily during work up process. Also, one equivalent of organometallic reagent is sufficient to complete this transformation. 相似文献
2.
Y. Kita S. Akai M. Yoshigi Y. Nakajima H. Yasuda Y. Tamura 《Tetrahedron letters》1984,25(52):6027-6030
Reaction of carboxylic acids with trimethylsilylethoxyacetylene in an inert solvent under mild conditions affords the corresponding carboxylic anhydrides in almost quantitative yields. 相似文献
3.
Audrey Serieys Fabrice Chemla Franck Ferreira Alejandro Pérez-Luna 《Tetrahedron letters》2008,49(36):5322-5323
The high yielding synthesis of symmetrical carboxylic anhydrides from acid chlorides mediated by zinc dust in the presence of dimethylformamide is presented. A mechanism involving the reductive insertion of zinc(0) into the C-Cl bond of a Vilsmeier-type iminium intermediate as the crucial step is also proposed. 相似文献
4.
《Tetrahedron》1988,44(9):2471-2476
Acyl chlorides and alkylchloroformates smoothly reacted with one molar equivalent of sodium hydxoxide, using liquid-liquid phase transfer conditions to afford high yields of the corresponding symmtrical carboxylic and carbonic hemiester anhydrides. Unstable, anhydrides such as 4-nitrobenzoïc, 2-furoïc and methacrylic anhydrides, which are otherwise difficult to obtain, were easily prepared by this method. The reaction mechanism does not seem to involve intermediate hydrolysis of half the acid chloride into the corresponding sodium carboxylate. 相似文献
5.
A simple, clean and highly efficient solvent-free procedure for the preparation of primary, secondary, tertiary and aromatic amides is described from the direct reaction of carboxylic acids and silica-supported ammonium salts, triethylamine (TEA) and tosyl chloride (TsCl) as condensing agent. The reaction proceeds rapidly in high yields at room temperature. 相似文献
6.
A. Khalafi-Nezhad A. Parhami A. Zare A. R. Moosavi Zare 《Journal of the Iranian Chemical Society》2008,5(3):413-419
A simple, clean and efficient solvent-free procedure for the preparation of aryl carboxylates is described from the direct reaction of carboxylic acids and phenols, in the presence of 1-methylimidazole as base and tosyl chloride (TsCl) as coupling agent. This method can be easily applied for different substituted phenols and carboxylic acids. It can also be applied for the selective acylation when other functional group such as hydroxyl is present on phenol ring. 相似文献
7.
Kazmierski I Bastienne M Gosmini C Paris JM Périchon J 《The Journal of organic chemistry》2004,69(3):936-942
The cross-coupling of various para- and meta-substituted aromatic bromides, mostly bearing sensitive moieties, with several carboxylic acid anhydrides is reported. This reaction can be carried out in two steps, by forming an aromatic organozinc reagent via cobalt catalysis in the first step, or even more interestingly in a single step, also by using a cobalt-based catalyst. The aromatic ketones are obtained by these new, mild, and convenient methods in 30-79% yields versus starting aryl bromide. Results are also disclosed that suggest the role played by cobalt species in the coupling of organozinc reagents with electrophiles could be similar to those of more commonplace transition metal complexes. 相似文献
8.
N,N-Diphenyl-p-methoxyphenylchloromethyleniminium chloride is found to be an effective condensation reagent of carboxylic acids and Grignard reagents under mild conditions to afford the corresponding ketones in high yields. 相似文献
9.
An efficient mixed reagent for direct synthesis of symmetrical carboxylic anhydrides from carboxylic acids has been prepared. Carboxylic acids are converted to anhydrides using triphenylphosphine/trichloroisocyanuric acid under mild reaction conditions at room temperature. Short reaction time, excellent yields of products, low cost, availability of reagents, simple experimental procedure, and easy work-up of the products are the main advantages of the presented method. 相似文献
10.
A mild method for the synthesis of 2-ketopyrroles from carboxylic acids via 2-pyridylthiolesters and pyrrylmagnesium chloride is described. 相似文献
11.
Fukuji Higashi Michihide Ozawa Teh-Chon Chang 《Journal of polymer science. Part A, Polymer chemistry》1985,23(5):1361-1367
A sulfonium salt derived from tosyl chloride and N-methylimidazole was successfully used as an effective condensing agent for the preparation of high-molecular-weight aromatic polyesters by the direct polycondensation of aromatic dicarboxylic acids and bisphenols. Conditions for the formation of the sulfonium salt and of the reaction of the salt with dicarboxylic acids favorable for the polycondensation were examined. Thermal property of a polymer was investigated in terms of random sequences of monomer in the polymer backbone. Preparation of a polyamide and a polyesteramide was attempted with limited success. 相似文献
12.
Direct synthesis of various oxazolines and 1,3,4-oxadiazoles from carboxylic acids was achieved using cyanuric chloride/indium under very mild conditions. 相似文献
13.
Triazolopyridines can be rapidly and efficiently synthesized from a variety of carboxylic acids with 2-hydrazinopyridines in one simple step. The use of commercially available PS-PPh3 resin combined with microwave heating delivered the product triazolopyridines in good yields and purities. 相似文献
14.
以95%乙醇作为溶剂,在三溴苯乙酮的存在下硫酚或硫醇发生自身偶联反应生成双硫化合物。这是继传统方法之后一种温和、操作简单、绿色并且无金属催化的合成方法。在优化反应条件下考察了多种苯硫酚和硫醇类化合物,发现芳环上连有供电基团的化合物比含吸电子基团的能获得更高的产率,并且反应时间更短;同时,以脂肪族和杂环类化合物为底物也有较高的产率。 相似文献
15.
Benzoxazoles or benzimidazoles can be rapidly and efficiently synthesized from a variety of carboxylic acids with 2-aminophenols or 1,2-phenylenediamines in one simple step, respectively. The use of commercially available PS-PPh3 resin combined with microwave heating delivered a variety of benzoxazoles and benzimidazoles in high yields and purities. 相似文献
16.
Georgios A. HeropoulosCarolina Villalonga-Barber 《Tetrahedron letters》2011,52(41):5319-5322
A highly efficient, mild, simple and clean procedure is presented for the one-pot oxidation of aromatic and aliphatic aldehydes to their corresponding ethyl esters using benzyl chloride as the oxidant under palladium-catalyzed conditions. The reaction is complete in just 30 min under microwave irradiation and inert conditions are not required to obtain good to excellent yields (65-93%) of isolated products. 相似文献
17.
18.
《Tetrahedron letters》1986,27(8):919-922
The transformation of cyclic anhydrides to their corresponding imides involves a mild three-step sequence: (1) reaction with a primary amine, (2) conversion of the intermediate monoamide to an N-hydroxysuccinimidyl ester using N,N′-disuccinimidyl oxalate (DSO), and (3) cyclization by heating the NHS ester in trichloroethylene in the presence of 4-(dimethylamino)pyridine. 相似文献
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20.
Hemaka A. Rajapakse Hong Zhu Mary Beth Young Bryan T. Mott 《Tetrahedron letters》2006,47(28):4827-4830
A convenient one pot method for the synthesis of 2,5-disubstituted 1,3,4-oxadiazoles from acids and acyl hydrazides is reported. Acid activation with CDI, followed by coupling with the desired acylhydrazide and dehydration in the same pot with Ph3P and CBr4 affords the corresponding 1,3,4-oxadiazoles in good yield. The scope of the acid and acylhydrazide components is presented. 相似文献