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1.
Popil'nichenko S. V. Brovarets B. S. Drach B. S. 《Russian Journal of Organic Chemistry》2004,40(2):219-220
2-Acylamino-3-chloroacrylonitriles prepared by treating available N-(1,2,2-trichloroethyl)amides of carboxylic acids with sodium cyanide readily undergo cyclization in the presence of excess hydrazine hydrate. The cyclization products, 5-amino-4-acylaminopyrazoles, were applied to the synthesis of new imidazo[4,5-c]pyrazole and pyrazolo[1,5-a]pyrimidine derivatives. 相似文献
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R. Alan Aitken Shaun T.E. Mesher 《Phosphorus, sulfur, and silicon and the related elements》2013,188(1-4)
Abstract There are currently few simple reagent systems available which can effect efficient kinetic resolution of racemic compounds. We report here a series of chiral bicyclic iminium salts, which can resolve racemic secondary alcohols to give both the unreacted alcohol and the sulphide resulting from reaction in moderate enantiomeric excess. 相似文献
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Frank Hoffmann Lothar Jäger Carola Griehl 《Phosphorus, sulfur, and silicon and the related elements》2013,188(2):299-309
The reactions of diphenoxyphosphoryl chloride ((PhO) 2 P(O)Cl) and different chlorophosphonium salts ([R 3 PCl]X, R = (CH 3 ) 2 N, pyrrolidine, X = PF 6 m , BF 4 m ), respectively, with 7-aza-1-hydroxybenzotriazole (HOAt), 1-hydroxybenzotriazole (HOBt), hydroximinomalonitrile (HOxDCO), and ethyl hydroximinocyanoacetate (HOxO) are described. The structures of the new compounds, which are useful coupling reagents for epimerization-free peptide segment condensation, are discussed on the basis of their 1 H, 13 C, 31 P NMR, and IR spectra. The reactions of (PhO) 2 P(O)Cl lead to mixtures of O - and N -phosphorylated isomers of varying ratios. Contrary, reactions of chlorophosphonium salts yield exclusively one isomer. 相似文献
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Paul Cowper Yu Jin Michael D. Turton Dr. Gabriele Kociok‐Köhn Dr. Simon E. Lewis 《Angewandte Chemie (International ed. in English)》2016,55(7):2564-2568
Azulenesulfonium salts may be readily prepared from the corresponding azulenes by an SEAr reaction. These azulene sulfonium salts are bench‐stable species that may be employed as pseudohalides for cross‐coupling. Specifically, their application in Suzuki–Miyaura reactions has been demonstrated with a diverse selection of coupling partners. These azulenesulfonium salts possess significant advantages in comparison with the corresponding azulenyl halides, which are known to be unstable and difficult to prepare in pure form. 相似文献
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Paul Cowper Yu Jin Michael D. Turton Gabriele Kociok‐Khn Simon E. Lewis 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2016,128(7):2610-2614
Azulenesulfonium salts may be readily prepared from the corresponding azulenes by an SEAr reaction. These azulene sulfonium salts are bench‐stable species that may be employed as pseudohalides for cross‐coupling. Specifically, their application in Suzuki–Miyaura reactions has been demonstrated with a diverse selection of coupling partners. These azulenesulfonium salts possess significant advantages in comparison with the corresponding azulenyl halides, which are known to be unstable and difficult to prepare in pure form. 相似文献
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Pil'o S. G. Brovarets V. S. Vinogradova T. K. Golovchenko A. V. Drach B. S. 《Russian Journal of General Chemistry》2002,72(11):1714-1723
Enamides of the general formula Cl2CÍC(X)NHCOR1, where X = CN, COOAlk, CONH2, P(O)(OEt)2, P(O)Ph2, +PPh3 Cl-, were treated in succession with alkane- or arenethiols and silver carbonate to obtain 5-alkyl(aryl)thio-2-R1-4-X-1,3-oxazoles with high selectivity. The latter were converted into the corresponding sulfonyl derivatives. Unlike 2-acylamino-3,3-dichloroacrylonitriles which react with sodium hydrogen sulfide in a nonselective fashion, reactions of derivatives like Cl(ArS)CÍC(CN)NHCOR1 with NaHS lead to hitherto unknown 5-arylthio-4-thiocarbamoyl-2-R1-1,3-oxazoles whose structure was confirmed both by spectral methods and by cyclocondensation with bromoacetophenone according to Hantzsch. Heating of some 2-aryl-5-mercapto-4-X-1,3-oxazoles with benzenethiols results in recyclization into the corresponding 2,4-disubstituted 5-arylthio-1,3-thiazoles, presumably due to prototropic tautomerism in the 5-mercaptooxazole fragment. 相似文献
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Péter Bánhegyi Frigyes Wáczek Zsolt Székelyhidi Bálint Hegymegi-Barakonyi György Kéri 《合成通讯》2013,43(19):3270-3276
An unusual chemical method has been applied for the preparation of 1-benzothiophene-3-carboxamide derivatives from esters by reaction with lithium amide in tetrahydrofurane. 相似文献
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Dikusar E. A. Akishina E. A. Petkevich S. K. Zhukouskaya N. A. Alekseyev R. S. Bumagin N. A. Shahab S. N. Filippovich L. N. Potkin V. I. 《Russian Journal of General Chemistry》2022,92(1):40-53
Russian Journal of General Chemistry - A convenient one-step method for the synthesis of new bisacridine derivatives, containing fragments of 5-arylisoxazoles, 4,5-dichloroisothiazole, as well as... 相似文献
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Photochemical Carbopyridylation of Alkenes Using N-Alkenoxypyridinium Salts as Bifunctional Reagents
Gangadhar Rao Mathi Yujin Jeong Yonghoon Moon Prof. Dr. Sungwoo Hong 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(5):2065-2070
N-Alkenoxypyridinium salts have been used as synthons for the umpolung reaction of enolates for the preparation of α-functionalized carbonyl compounds. In contrast, we found that the photoreduction of N-alkenoxypyridinium salts generates α-carbonyl radicals after cleavage of the N−O bond, thereby allowing simultaneous incorporation of α-keto and pyridyl groups across unactivated alkenes. In the process, the formed α-carbonyl radicals engage unactivated alkenes to afford alkyl radical intermediates poised for subsequent addition to pyridinium salts, which ultimately affords a variety of γ-pyridyl ketones under mild reaction conditions. This transformation is characterized by a broad substrate scope and good functional-group compatibility, and the utility of this transformation was further demonstrated by the late-stage functionalization of complex biorelevant molecules. 相似文献
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Shuo Wang Prof. Igor Larrosa Prof. Dr. Hideki Yorimitsu Dr. Gregory J. P. Perry 《Angewandte Chemie (International ed. in English)》2023,62(14):e202218371
The potassium salts of carboxylic acids are developed as efficient carboxylating agents through CO2 exchange. We describe these carboxylates as dual-function reagents because they function as a combined source of CO2 and base/metalating agent. By using the salt of a commercially available carboxylic acid, this protocol overcomes difficulties when using CO2 gas or organometallic reagents, such as pressurized containers or strictly inert conditions. The reaction proceeds under mild conditions, does not require transition metals or other additives, and shows broad substrate scope. Through the preparation of several biologically important molecules, we show how this strategy provides an opportunity for isotope labeling with low equivalents of labeled CO2. 相似文献
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《Analytical letters》2012,45(19-20):1881-1891
Abstract A method for spectrophotometric determination of palladium by complexation with Arylidene-2-pyridylhydrazone derivatives in 50% (V/V) ethanolic solution are described-Pd(II) forms a 1:1 complex with the reagents. Beer's law is obeyed over the range 0.2-6.5 μg ml?1. The effect of pH, effect of excess reagent, stability of complexes as well as the tolerance amount of many metal ions have been reported. The method is applied, with fair accuracy, to the determination of pd(II) in synthetic solutions. 相似文献
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Aliphatic and aromatic Grignard reagents have been found to add to the double bond of 1, 3-disubstituted benzimidazolium salts. The resulting substituted benzimidazolines were hydrolyzed and the aldehydes converted directly to their 2, 4-dinitrophenylhydrazone derivatives. The scope and limitations of this synthesis are discussed. 相似文献
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Obushak N. D. Matiichuk V. S. Vasylyshin R. Ya. Ostapyuk Yu. V. 《Russian Journal of Organic Chemistry》2004,40(3):383-389
Meerwein reaction of arenediazonium chlorides with acrolein gave 3-aryl-2-chloropropanals which were brought into cyclocondensation with thiourea. The resulting 2-amino-5-benzyl-1,3-thiazoles were acylated with carboxylic acid chlorides and phthalic anhydride to afford, respectively, 2-acylamino-5-benzyl-1,3-thiazoles and N-(5-benzyl-1,3-thiazol-2-yl)phthalimides. 相似文献
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The reactions of the di(acid chloride) of 2-carboxy-3,4-dimethoxyphenylthiopyruvic acid with 1-aminoadamantane and with thiosemicarbazide take place with the closure of a seven-membered ring and the formation of 1,2-dihydro-(3H)-2-benzazepine-1,3-dione. On reaction with monochloroacetic acid, 4-mercapto-8, 9-dimethoxy-2-(N-thioureido)-1, 2-dihydro-(3H)-2-benzazepine-3-dione is converted into a derivative of thiazolidine-2,4-dione 2-hydrazone, which readily takes part in condensation reactions with oxo compounds forming 5-ylidene derivatives.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 29–32, January, 1984. 相似文献