Cycloaddition
Mostrando 13-24 de 71 artigos, teses e dissertações.
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13. SÍNTESE E AVALIAÇÃO DA ATIVIDADE CITOTÓXICA DE DERIVADOS DO EUGENOL CONTENDO NÚCLEOS 1,2,3-TRIAZÓLICOS
Eugenol is an aromatic compound found in several plant species. It presents important biological activities including cytotoxicity. In this paper, it is described the synthesis and the evaluation of the cytotoxic activity of eugenol derivatives bearing 1,2,3-triazole functionalities. Eugenol, extracted via hydrodistillation from dried flower buds of Eugenia
Quím. Nova. Publicado em: 2018-05
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14. Synthesis and Cytotoxic Evaluation of 1H-1,2,3-Triazol-1-ylmethyl-2,3-dihydronaphtho[1,2-b]furan-4,5-diones
ABSTRACT The 1,2-naphthoquinone compound was previously considered active against solid tumors. Moreover, glycosidase inhibitors such as 1,2,3-1H triazoles has been pointed out as efficient compounds in anticancer activity studies. Thus, a series of eleven 1,2-naphthoquinones tethered in C2 to 1,2,3-1H-triazoles 9a-k were designed, synthesized and their cyto
An. Acad. Bras. Ciênc.. Publicado em: 15/02/2018
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15. Synthesis by Click Reactions and Antiplasmodial Activity of Lupeol 1,2,3-Triazole Derivatives
Lupeol, a triterpene frequently found in Asteraceae plant species, showed moderate to low activity in different strains of Plasmodium falciparum, the most virulent malaria etiological agents. In this work, lupeol was isolated from Parahancornia fasciculata, a plant that is used to treat malaria in the Amazonia region. In the search of more activity lupeol de
J. Braz. Chem. Soc.. Publicado em: 2017-10
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16. Effect of Sulfamic Acid on 1,3-Dipolar Cycloaddition Reaction: Mechanistic Studies and Synthesis of 4-Aryl-NH-1,2,3-triazoles from Nitroolefins
A facile and new metal-free 1,3-dipolar cycloaddition reaction for the synthesis of 4-aryl-NH-1,2,3-triazoles from nitroolefins and NaN3 employing NH2SO3H has been developed. Sulfamic acid proved to be an efficient additive in this transformation by inhibiting the formation of triaryl benzene. Mechanistic aspects and key intermediates associated with this tr
J. Braz. Chem. Soc.. Publicado em: 2017-04
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17. Strategies for Molecular Diversification of 2-[Aminoalkyl-(1H-1,2,3-triazol-1- yl)]-1,4-naphthoquinones Using Click Chemistry
Click chemistry-based strategies for the synthesis of 2-amino-alkyl-1,2,3-triazole-1,4-naphthoquinone derivatives make it possible to obtain desired products from 1,4-naphthoquinone (1,4-NQ), and bio-based lawsone, nor-lapachol and lapachol. The first route (Strategy A) starting from 1,4-NQ and amino alcohols, then 2-amino-alkyl-1,4-NQ alcohols, were tosylat
J. Braz. Chem. Soc.. Publicado em: 2017-04
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18. An Efficient Protocol for Facile Synthesis of New 5-Substituted-1H-Tetrazole Derivatives Using Copper-Doped Silica Cuprous Sulfate (CDSCS) as Heterogeneous Nano-Catalyst
A facile and highly efficient protocol for synthesis of new 5-substituted-1H-tetrazoles derivatives using copper-doped silica cuprous sulfate (CDSCS) is described. In this method, the cycloaddition reaction of sodium azide with structurally diverse nitriles involving bioactive N-heterocyclic cores exploiting CDSCS in refluxing H2O/i-PrOH (1:1, v/v) furnishes
J. Braz. Chem. Soc.. Publicado em: 2017-01
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19. Ultrasound-Assisted Synthesis of Isatin-Type 5'-(4-Alkyl/Aryl-1H-1,2,3-triazoles) via 1,3-Dipolar Cycloaddition Reactions
This short report describes the preparation of twelve isatin derivatives, 5'-(4-alkyl/aryl-1H-1,2,3-triazoles), using 5-azido-spiro[1,3-dioxolane-2,3'-indol]-2'(1'H)-one in the presence of various alkynes under acidic conditions and ultrasound irradiation. Compared with conventional methods, yields increased to 78-98%, and reaction times decreased to 5 min.
J. Braz. Chem. Soc.. Publicado em: 2016-12
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20. NMR Studies on [2 + 3] Cycloaddition of Nitrile Oxides to Polyunsaturated Medium Size Rings
Site selectivity, regioselectivity and stereoselectivity of [2 + 3] cycloaddition of 4-trifluoromethylbenzonitrile oxide to polyunsaturated medium size rings including 1,5,9-cyclododecatriene, 11-membered sesquiterpenes, 1,3-cyclooctadiene and 5-vinyl-2-norbornene were examined. Site selectivity was correlated with electron charges of alkenyl carbon atoms. S
J. Braz. Chem. Soc.. Publicado em: 2016-11
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21. The 1,3-Dipolar Cycloaddition of Nitrile Oxide to Vinylacetic Acid: Computational Study of Transition States Selectivity, Solvent Effects, and Bicyclo Formation
The 1,3-dipolar cycloaddition reaction is a powerful tool for the cycloaddition of nitrile oxides to olefins, and this reaction is of considerable interest to obtain isoxazolines. Density functional theory (DFT) was used to study the 1,3-dipolar cycloaddition reaction mechanism that initially occurs between benzonitrile oxide and vinylacetic acid to yield a
J. Braz. Chem. Soc.. Publicado em: 2016-06
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22. Synthesis, in vitro Antimalarial Activity and in silico Studies of Hybrid Kauranoid 1,2,3-Triazoles Derived from Naturally Occurring Diterpenes
We herein report the synthesis of hybrid kauranoid molecules of type 1,2,3-triazole-1,4-disubstituted aiming to improve the antimalarial activity of kaurenoic and xylopic acids. The CuI-catalyzed cycloaddition of azides and kauranoid terminal alkynes was explored as a hybridization strategy. Kauranoid terminal alkynes were prepared from kaurenoic and xylopic
J. Braz. Chem. Soc.. Publicado em: 2016-03
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23. Synthesis of 3-(1H-1,2,3-Triazol-1-yl)-2-(arylselanyl)pyridines by Copper-Catalyzed 1,3-Dipolar Cycloaddition of 2-(Arylselanyl)-3-azido-pyridines with Terminal Alkynes
We present here our results in the synthesis of eleven new 3-(1H-1,2,3-triazol-1-yl)-2-(arylselanyl)pyridines by copper-catalyzed azide-alkyne cycloaddition reactions. The reactions were performed in the presence of catalytic amount of copper(II) acetate and sodium ascorbate using a mixture of tetrahydrofuran/water (1:1) as solvent at room temperature in air
J. Braz. Chem. Soc.. Publicado em: 2015-11
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24. Efficient Eco-Friendly Solvent-Free Click Synthesis and Antimicrobial Evaluation of New Fluorinated 1,2,3-Triazoles and their Conversion into Schiff Bases
A facile and convenient green click synthesis has been developed for the preparation of new fluorinated 1,2,3-triazoles under solvent-free conditions via a Huisgen 1,3-dipolar cycloaddition reaction between dimethylacetylene dicarboxylate (DMADC) and fluorophenyl azides in excellent yields within 2 min. Treatment of the resulting diesters with hydrazine hydr
J. Braz. Chem. Soc.. Publicado em: 2015-10