共查询到20条相似文献,搜索用时 15 毫秒
1.
David Thomae Dorothée Henryon Serge Schneider Gilbert Kirsch Pierre Seck 《Tetrahedron》2009,65(50):10453-1313
In this work, we described the synthesis of new tetrasubstituted thiophenes and selenophenes achieved by an easy one-pot four-step procedure. Expected compounds were obtained in good yield from ketene dithioacetals. 相似文献
2.
In this work, we described an easy preparation of substituted 4-amino-5-cyano-1,3-thiazoles. These compounds have been used as starting materials to obtain two classes of compounds. New substituted [1,3]thiazolo[4,5-e]pyridines were synthesized in one step via Friedländer reaction. Diazotation of 4-amino-5-cyano-1,3-thiazoles afforded 4-chloro[1,3]thiazolo[4,5-d][1,2,3]triazines in one step. The later was substituted by a secondary amine to obtain substituted 4-amino[1,3]thiazolo[4,5-d][1,2,3]triazines. 相似文献
3.
Richard Kammel Denisa Tarabová Břetislav Brož Veronika Hladíková Jiří Hanusek 《Tetrahedron》2017,73(14):1861-1866
The reaction of 3-bromooxindole with substituted (hetero)aromatic thioamides in acetonitrile was studied. At room temperature the reaction preferably gives products of ring transformation i.e. 2-aryl-5-(2-aminophenyl)-4-hydroxy-1,3-thiazoles (3b-f,h) whereas at elevated temperature products of an Eschenmoser coupling reaction, i.e. 3-[amino(aryl)-methylidene]-1,3-dihydro-2H-indol-2-ones (2b-f), are formed exclusively. There exist only two exceptions (4-methoxy and 2-pyridinthioamide) in which the Eschenmoser coupling reaction always takes place giving 2a and 2g. Also N-methylation of the starting 3-bromooxindole completely prevents formation of thiazoles. The prepared thiazoles 3b-f are unstable in solution and they undergo slow ring transformation to 2b-f. The rate limiting step of this rearrangement involves cleavage of an intermediary thiirane ring, which is slowed down by electron-withdrawing substituents on the thioamide (ρ = ?1.15). 相似文献
4.
A. A. Konarev 《Russian Journal of Electrochemistry》2007,43(10):1206-1210
The synthesis of 1,3-dimethyl-4-amino-5-formyluracyl, an intermediate of theophylline synthesis, was studied in an ammonium chloride medium using the electroreduction of 1,3-dimethyl-4-amino-5-nitrosouracyl to a diamino derivative with its further formylation. The electrolysis and formylation conditions were optimized. The reduction of 1,3-dimethyl-4-amino-5-nitrosouracyl was performed under the following conditions: its concentration was 12.0–13.5 %, the cathode was a Kh18N10T stainless steel gauze, the electrolysis was performed in the presence of ammonium chloride, the current density was 7.5–8.0 A/dm2, the electrolysis temperature was 40–45°C, and the formylation temperature was 71–72°C. The substance yield of overall formylaminouracyl was 81.2–83.3% and the current efficiency was 62.0–64.5%. The developed process of 1,3-dymethyl-4-amino-5-formyluracyl synthesis was evaluated at a scaled-up laboratory setup with a filter-press cell. 相似文献
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6.
Robert N. Hanson 《Journal of heterocyclic chemistry》1984,21(1):57-59
The diketones 3 and 7 were brominated to give the bromomethyldiketones 4 and 8 which were condensed with selenourea and thiourea to give the corresponding 2-amino-1,3-selenazoles 5a, 9a and 2-amino-1,3-thiazoles 5b, 9b . Reaction with acetic anhydride and benzoic anhydride yielded the 2-acylated derivatives. Biologic evaluation of these compounds indicated some activity as adrenocortical enzyme inhibitors, but significantly less than that of metyropone. 相似文献
7.
A tandem aza-Friedel-Crafts reaction/Hantzsch cyclization is described to access various polysubstituted 2-amino-1,3-thiazoles from electron-rich (hetero)-aromatic rings, aldehydes, thiourea and α-chloroketones. 相似文献
8.
Kiumars Bahrami Mohammad M. Khodaei Akbar Nejati 《Monatshefte für Chemie / Chemical Monthly》2011,15(1):159-162
Abstract
ZnO is an efficient, readily available, and reusable catalyst for the one-pot synthesis of 1,2,4,5-tetrasubstituted and 2,4,5-trisubstituted imidazoles. This procedure is very simple and affords excellent yields. 相似文献9.
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12.
Methods for the synthesis of 1,3-dithiole-2-thiones, based on [4+2] cycloaddition of the 1,3-dithiole-2,4,5-trithione oligomer
to various unsaturated acyclic, carbocyclic, and heterocyclic compounds, are reviewed. Methods for the production of substituted
tetrathiafulvalenes, which can be regarded as derivatives of bis(ethylenedithio)tetrathiafulvalene, from 1,3-dithiole-2-thiones
synthesized by this method are described.
Dedicated to the memory of Professor O. Neilands.
__________
Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 483–502, April, 2006. 相似文献
13.
The synthesis of the first series of 5-alkoxy-1,3-thiazole-based liquid crystals is reported. The aforementioned liquid crystals were synthesised through a Lawesson's reagent-mediated cyclisation of appropriate α-benzamido esters. This methodology was found to be highly efficient, even on a large scale, and the resulting 5-alkoxy-1,3-thiazoles could be purified without the use of column chromatography. The synthesis and mesomorphic properties of a family of 5-alkoxy-2-(4-cyanophenyl)-1,3-thiazole liquid crystals prepared via this approach are discussed and compared with their thiophene and phenyl analogues. 相似文献
14.
Ankita RaiLal Dhar S. Yadav 《Tetrahedron letters》2011,52(30):3933-3936
The first one-pot three-component coupling reaction of O,O-diethyl hydrogen phosphorodithioate, aldehydes, and aldimines affording 1,2,4-trisubstituted 1,3-thiazetidines is reported. The product is obtained in moderate to high yields (45-94%) and has excellent diastereoselectivity (90-96%) in favour of the cis isomer. Shorter reaction times, ambient temperature, operational simplicity, and high yields are the salient features of the present procedure. 相似文献
15.
2-Trifluoromethyl and 2-difluoromethyl substituted benzimidazole, benzoxazole and benzothiazole derivatives were efficiently prepared through a one-pot reaction of trifluoroacetic acid and difluoroacetic acid, respectively, with commercially available o-phenylenediamines, 2-aminophenols, and 2-aminobenzenethiols in good to excellent yields. Subsequential bromination of 2-difluoromethyl groups by photolysis with NBS led to the formation of bromodifluoromethyl benzo-1,3-diazoles which may be utilized to prepare the new generation of gem-difluoromethylene linked identical or non-identical twin molecules for drug synthesis. 相似文献
16.
Julia Kuchar Katharina Reinhold Vera Rsgen Nils Nthling Christian W. Lehmann Fabian Mohr 《Molecules (Basel, Switzerland)》2021,26(24)
A series of 2-arylamino-1,3-selenazoles was synthesized and their reactivity was studied. The 2-arylamino-1,3-selenazoles and their reaction products were characterized by various spectroscopic methods and X-ray diffraction. In addition, the antimicrobial activity of the 2-arylamino-1,3-selenazoles in a panel of seven bacteria and fungi was examined. 相似文献
17.
O. V. Dyablo A. F. Pozharskii V. V. Kuz'menko M. A. Kolesnichenko 《Chemistry of Heterocyclic Compounds》2001,37(5):567-573
The amination of 3-amino- and 3-azidoindazoles by hydroxylamine-O-sulfonic acid in an alkaline medium yields previously unreported 1,3-diamino- and 1-amino-3-azidoindazoles. These products undergo slow autoxidation in chloroform solution to give 4-aminobenzo-1,2,3-triazine. The action of formic or acetic acid on 3-amino-1-benzylideneaminoindazole leads to recyclization and formation of 3-amino-2-benzylindazole, which is also formed in the catalytic hydrogenation of 1-benzylamino-3-nitro- and 1-benzylideneamino-3-nitroindazoles. 相似文献
18.
Summary N-bridged 1,3-thiazolium-4-olates were synthesized by reaction of 3-substituted 3-aminothioacrylanilides with bromoacetic acid ethyl ester in refluxing xylene. Their structural aspects were investigated by means of mass, NMR, and absorption spectroscopy. They display an unusual ring-chain tautomeric equilibrium, which is governed by the nature of the solvents and thepH value.
Synthese und Eigenschaften einzigartiger Mesoionischer 1,3-Thiazolium-4-olate
Zusammenfassung N-verbrückte 1,3-Thiazolium-4-olate wurden durch Reaktion von 3-substitutierten 3-Aminothioacrylaniliden mit Bromessigsäureethylester in siedendem Xylol synthetisiert. Ihre strukturellen Aspekte wurden mit Hilfe von Massen-, NMR- und Absorptionsspektroskopie untersucht. Sie zeigen ein ungewöhnliches Ring-Ketten-Tautomeriegleichgewicht, das durch die Natur des Lösungsmittels und denpH-Wert gesteuert wird.相似文献
19.
Sodium fluoride was found to be a simple, mild and efficient catalyst for the synthesis of 2,4-disubstituted 1,3-thiazoles and selenazoles utilizing phenacyl bromides/3-(2-bromoacetyl)-2H-chromen-2-one and thiourea/phenylthiourea/selenourea in aqueous methanol at ambient temperature. Analytically pure products are formed within 1–3 min in excellent yields. 相似文献
20.
A one-pot, five-component strategy toward the synthesis of new indole substituted pyrrolidine and pyrrolizidine heterocycles through 1,3-dipolar cycloaddition reactions using ninhydrin, 1,2-phenylenediamine, amino acids, 3-cyanoacetyl indoles and aryl aldehydes is described. The features of this procedure were characterized by the mild reaction conditions, high yields, one-pot procedure, and operational simplicity. 相似文献