1 3 Dipolar
Mostrando 1-12 de 115 artigos, teses e dissertações.
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1. HUISGEN AND HIS ADVENTURES IN A PLAYGROUND OF MECHANISMS AND NOVEL REACTIONS
The death of professor Rolf Huisgen (1920-2020) was announced on March 26th 2020, in the midst of the COVID-19 pandemic. Professor Huisgen was professor emeritus at the University of Munich in Germany, and studied in detail the mechanism of the 1,3-dipolar cycloaddition reaction, significantly expanding its scope. Even though he did not discover this reactio
Quím. Nova. Publicado em: 2021-02
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2. Functionalization of P3HT with Various Mono- and Multidentate Anchor Groups
Due to its favorable optoelectronic properties and the accessibility via Grignard metathesis (GRIM) polymerization, poly(3-hexylthiophene) (P3HT) is one of the most applied conjugated polymers. The ‘living' nature of GRIM polymerization enables the modification of the polymer and the installation of desired properties. In the present study, two versatile a
J. Braz. Chem. Soc.. Publicado em: 2018-05
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3. 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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4. 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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5. 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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6. How Accurate is the SMD Model for Predicting Free Energy Barriers for Nucleophilic Substitution Reactions in Polar Protic and Dipolar Aprotic Solvents?
In the past seven years, the SMD (Solvent Model Density) method has been widely used by computational chemists. Thus, assessment on the reliability of this model for modeling chemical process in solution is worthwhile. In this report, it was investigated six anion-molecule nucleophilic substitution reactions in methanol and dipolar aprotic solvents. Geometry
J. Braz. Chem. Soc.. Publicado em: 2016-11
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7. 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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8. 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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9. 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
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10. Synthesis and in vitro evaluation of novel galactosyl-triazolo-benzenesulfonamides against Trypanosoma cruzi
Os únicos fármacos aprovados para o tratamento da doença de Chagas, nifurtimox e benznidazol, apresentam efeitos colaterais e eficácia limitada na fase crônica da doença, destacando a necessidade de novos fármacos. Entre os diferentes alvos moleculares de fármacos identificados no parasita, uma trans-sialidase de Trypanosoma cruzi (TcTS) tem sido con
J. Braz. Chem. Soc.. Publicado em: 2014-10
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11. A facile regioselective synthesis of novel spiroacenaphthene pyrroloisoquinolines through 1,3-dipolar cycloaddition reactions
Se descreve um procedimento eficiente de três componentes em uma única operação para a síntese de novas espiroacenafteno pirroloisoquinolinas com alta regiosseletividade. Estes compostos foram preparados pela cicloadição 1,3-dipolar de uma ilida azometínica gerada a partir da acenaftenoquinona e 1,2,3,4-tetraidroisoquinolina, via deslocamento [1,5]-H
J. Braz. Chem. Soc.. Publicado em: 2013-12
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12. NMR studies on 1,3-dipolar cycloaddition of nitrile oxides to norbornenes
A reação de cicloadição 1,3-dipolar de óxidos de nitrila a norbornanos substituídos com um grupo derivado de acrilato foi examinada. Somente adutos para o sistema norbornano foram formados com boa exo seletividade e completa seletividade ao sítio. As estruturas dos produtos foram elucidadas através das técnicas de espectrometria de massas com ioniza
J. Braz. Chem. Soc.. Publicado em: 2013-05