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1.
Kodam Sujatha 《合成通讯》2018,48(3):302-308
An expeditious one pot method has been developed for the synthesis of 2,4-disubstituted thiazoles under solvent free conditions via a multicomponent approach. Substituted thiazoles were synthesized with high yields by the reaction of cyclic ketones, thiosemicarbazide, and phenacyl bromides or 3-(2-bromoacetyl)-2H-chromen-2-ones in a shorter reaction time with high purity via simple purification technique. 相似文献
2.
Summary A new example of a selective halogen dance reaction was observed upon lithiation of 2-bromo-5-methylthiophene withLDA under appropriate reaction conditions. A series of 2-substituted 3-bromo-5-methylthiophenes was prepared by reacting the thus selectively generated intermediate 3-bromo-2-lithio-5-methylthiophene with various electrophiles to study scope and limitations of the reaction.Dedicated to Prof. emeritusHans Suschitzky, University of Salford, UK, on the occasion of his 80th birthday 相似文献
3.
Luigino Troisi Catia GranitoSerena Perrone Francesca Rosato 《Tetrahedron letters》2011,52(33):4330-4332
A novel and simple synthetic methodology, based on palladium-catalyzed cyclocarbonylation reaction, is presented for preparing five- and six-membered benzo-fused heterocycles. A mechanism for the process is also proposed and discussed. 相似文献
4.
Summary New trisubstituted furans exhibiting two different substitution patterns were synthesizedvia lithiation of 2-bromo-5-methylfuran. Choice of appropriate reaction parameters enabled selective halogen dance reactions, affording 2-substituted 3-bromo-5-methylfurans upon quenching with various electrophiles. Moreover, from the same starting material also complete prevention of halogen migration could be achieved, thus providing selective access to 3-substituted 2-bromo-5-methylfurans.
Synthese dreifachsubstituierter Furane aus 2-Brom-5-methylfuranvia Halogenwanderung und deren selektiver Verhinderung
Zusammenfassung Durch Lithiierung von 2-Brom-5-methylfuran konnten Furane mit zwei verschiedenen Substitutionsmustern synthetisiert werden. Es wurden Reaktionsbedingungen für eine kontrollierte Halogenwanderungsreaktion entwickelt, durch die nach Quenchen mit verschiedenen Elektrophilen 2-substituierte 3-Brom-5-methylfurane erhalten wurden. An demselben Edukt konnte auch vollständige Hintanhaltung der Umlagerung erzielt werden, wodurch Zugang zu 3-substituierten 2-Brom-5-methylfuranen geschaffen wurde.相似文献
5.
Lei Zhou 《Tetrahedron letters》2007,48(48):8449-8452
A phosphine- and copper-free protocol for the synthesis of phthalides via Pd/CNTs-catalyzed tandem coupling-cyclization process has been developed. The palladium immobilized on CNTs showed high catalytic activity, and the reactions with a variety of terminal alkynes and o-iodobenoic acid proceeded smoothly to give phthalides in moderate to good yields catalyzed by 0.1% mmol Pd/CNTs. 相似文献
6.
Yunlan Li Qiurui Zhang Xuefeng Xu Xu Zhang Yurong Yang Wei Yi 《Tetrahedron letters》2019,60(14):965-970
Described herein is a new and general method for one-pot synthesis of 2,4-disubstituted quinolines via silver-catalyzed [3?+?1?+?2] annulation of simple amines, alkyne esters and terminal alkynes. The versatile transformation might initiate with the facile formation of the enamine species with the feature of good to excellent yields, exclusive regioselectivity, and excellent substrate/functional group tolerance. 相似文献
7.
Björn C.G. Söderberg Jeremiah W. Hubbard Stacey R. Rector Shannon N. O'Neil 《Tetrahedron》2005,61(15):3637-3649
A route to 3,4-fused indoles via two consecutive palladium-catalyzed reactions; an intramolecular Heck reaction followed by a reductive N-heteroannulation is described. Using this route, a number of indoles have been prepared having a variety of ring sizes anchored to the 3- and 4-position of the indole nucleus. Furthermore, a number of functional groups, both carbon and heteroatom substituents can be introduced in (and on) the additional ring without any detrimental effects on the two reactions. 相似文献
8.
Dan Feng Huang Hai Feng Wang Chang Ming Xu Teng Niu Yu Lai Hu College of Chemistry Chemical Engineering Northwest Normal University Lanzhou China 《中国化学快报》2010,(5)
<正>2,5-Disubstituted tetrahydrofurans were obtained from lactones and organozinc halides in moderate to high yield in the presence of Lewis acids. 相似文献
9.
K. Popov-Pergal M. Pergal J. Csanadi D. Djokovic 《Chemistry of Heterocyclic Compounds》2005,41(12):1529-1533
Potential antihistamines 5-arylidene-3-(4′-bromobenzyl)thiazolidine-2,4-diones were synthesized using 5-arylidenethiazolidine-2,4-dione
potassium salt and 4-bromobenzyl bromide in dry acetone. The log P values are given for all the synthesized compounds.
Published in Khimiya Geterotsiklicheskikh Soedinenii, No. 12, pp. 1854–1858, December, 2005. 相似文献
10.
K. Popov-Pergal L. Cuckovic M. Rancic M. Pergal D. Djokovic 《Chemistry of Heterocyclic Compounds》2003,39(8):1090-1093
A series of methyl 2-(arylidene-2,4-dioxotetrahydrothiazol-3-yl)propionates were prepared. A study of the 3D structure was performed. The log P values are given for all the synthesized compounds. 相似文献
11.
An efficient one-pot two-step synthesis of polysubstituted furans is described using readily available 4,5-epoxy-2-alkynyl esters as starting materials. In the first step, reduction of these with SmI2 affords buta-1,2,3-trienyl carbinol intermediates which, in the second step, participate in Pd(0)-catalyzed cyclization reactions with aryl halides and triflates by a mechanism probably involving oxidative addition, intramolecular oxypalladation and reductive elimination steps. In this manner, up to four carbon substituents are incorporated onto the furan ring, with the aryl group being introduced at the furan 3- or 4-positions. These features make the method particularly suitable for regioselective synthesis of tetrasubstituted furans. 相似文献
12.
Soumita Mukherjee 《合成通讯》2013,43(13):1939-1943
Direct metallation of 2,4-dialkoxy-5-bromopyrimidine with lithium diisopropylamide and consequent trapping by dimethylformamide resulted unexpectedly in the formation of 2,6-dialkoxy-5-dimethylaminopyrimidine-4-carboxaldehyde via displacement of bromine by dimethylamine moiety of dimethylformamide. 相似文献
13.
A simple and efficient synthesis of 5-arylidene-2,4-thiazolidinediones by the Knoevenagel condensation of aldehydes with 2,4-thiazolidinedione in the presence of 2-hydroxy ethylammonium propionate under solvent-free conditions is described. The attractive features of this procedure are operational simplicity, high yields, short reaction times, easy to prepare the catalyst, mild and environmentally benign reaction conditions, and recycle of the catalyst. 相似文献
14.
15.
Quansehng Ding Dongjian Zhu Huile Jin Jiuxi Chen Jinchang Ding Huayue Wu 《Phosphorus, sulfur, and silicon and the related elements》2013,188(2):220-224
Abstract An efficient and facile synthesis of 2,4-disubstituted thiazoles is achieved by a one-pot reaction of aldehydes and α-bromoketones with thiosemicarbazide by grinding under catalyst- and solvent-free conditions. This method has notable advantages in terms of simple workup, neat conditions, high yield, reasonably rapid reaction rate, and environmental friendliness. Supplemental materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements to view the free supplemental file. GRAPHICAL ABSTRACT 相似文献
16.
A series of 2,4-dichloro-5-fluorophenyl substituted arylidenetriazolothiazolidinones were obtained by one-pot reaction of
3-(2,4-dichloro-5-fluorophenyl)-4H-1,2,4-triazole-5-thiol with substituted benzaldehydes and monochloroacetic acid in the presence of acetic anhydride, acetic
acid, and sodium acetate. The structures of the newly synthesized compounds were characterized and confirmed by IR, 1H NMR, mass spectra, and elemental analysis. Compounds bearing the 4-methylthiophenyl, 3,4-methylenedioxyphenyl, and 2,3,5-trichlorophenyl
moiety showed excellent antiinflammatory activity. The antimicrobial screening studies revealed that compounds with 4-anisyl,
4-methylthiophenyl, 3,4-methylenedioxyphenyl, and 2,3,5-trichlorophenyl at position 5 of the arylidenetriazolothiazolidinone
moiety showed excellent activity against all tested strains at 6.25 μg cm−3 concentrations.
Correspondence: Mari Sithambaram Karthikeyan, Department of Chemistry, Mangalore University, Mangalagangothri 574199, Karnataka,
India. 相似文献
17.
G. V. Bozhenkov G. G. Levkovskaya A. N. Mirskova L. I. Larina 《Chemistry of Heterocyclic Compounds》2005,41(7):854-860
A method has been developed for obtaining 3-alkyl(phenyl)-4(5)-chloro-1-(2,4-dinitrophenyl)pyrazoles from appropriate dinitrophenylhydrazones
of 1-chloro-, 1,2-, and 2,2-dichlorovinyl ketones by heating the latter in polyphosphoric acid. The structure of the pyrazoles
was studied by IR and 1H NMR spectroscopy.
__________
Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 1012–1019, July, 2005. 相似文献
18.
AbstractHerein, we describe a one-pot synthesis of some novel 2-(3-alkyl/aryl-5-trifluoromethylpyrazol-1-yl)-4-(coumarin-3-yl)thiazoles (6) involving the reaction of 3-alkyl/aryl-5-hydroxy-5-trifluoromethyl-4,5-dihydropyrazole-1-thiocarboxamides (3) with 3-bromoacetylcoumarins (5) in the presence of sodium carbonate in ethanol. Reaction of 3 with 5 in the absence of sodium carbonate, however, resulted in the formation of 2-(3-alkyl/aryl-5-hydroxy-5-trifluoromethyl-4,5-dihydropyrazol-1-yl)-4-(coumarin-3-yl)thiazoles, which were subsequently dehydrated to 6 by refluxing in ethanol in the presence of sodium carbonate. The structure of the synthesized compounds (6) was confirmed by infrared (IR), mass, 1H NMR, and 13C NMR spectra and elemental analysis data. Newly synthesized compounds (6) showed moderate to good activity against Gram-positive bacteria. 相似文献
19.
Patrick Fresneau Jean-Marc Morand Franois Thomasson Max Cussac 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》1999,55(14):2893
Derivatives of 5-arylmethylene-2,4-imidazolidinediones and 5-arylmethylene-2-thioxo-4-imidazolidinones were synthesized as potential aldose reductase inhibitors (ARI). The Z/E configuration was elucidated by homonuclear NOE difference spectra and by proton-carbon coupling constant measurement from 13C coupled spectra using GATEDEC and SFDEC programs. 相似文献
20.
Ricardo C. Calhelha 《Tetrahedron letters》2010,51(2):281-283
Two methyl 3-aminothieno[3,2-b]pyridine-2-carboxylates were prepared from 3-fluoro or 3-nitropicolinonitriles and methyl thioglycolate in DMF/KOH(aq). From the unsubstituted precursor in the pyridine ring, di(hetero)arylamines were obtained by C-N Buchwald-Hartwig coupling with bromonitrobenzenes and with 2-bromopyridine. In the latter case a tetracyclic compound was formed by intramolecular cyclization. Using a brominated derivative in the pyridine ring as a coupling component, it was possible to synthesize C-C (Suzuki and Sonogashira) and C-N (Buchwald-Hartwig) coupling products and a tetracyclic compound obtained by bifunctionalization of the thienopyridine system. 相似文献