Cyclocondensation
Mostrando 1-12 de 30 artigos, teses e dissertações.
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1. Efficient Synthesis and Antimicrobial Activities of Long Alkyl Chain Trifluoromethyl-1H-pyrazol-1-(thio)carboxamides and Trifluoromethyl-1H-pyrazol-1-yl-thiazoles
The synthesis of 3-alkyl-5-trifluoromethyl-1H- pyrazole-1-carboxamides, 3-alkyl-5-trifluoromethyl-1H-pyrazole-1-thiocarboxamides, and 2-(3-alkyl-5-trifluoromethyl-1H-pyrazol-1-yl)-thiazoles derivatives are reported. [3 + 2] cyclocondensations for a series of long alkyl chain 1,1,1-trifluoro-4-methoxyalk-3-en-2-ones and semicarbazide or thiosemicarbazide were
J. Braz. Chem. Soc.. Publicado em: 2021-04
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2. Ultrasound-Promoted Synthesis, Structural Characterization and in vitro Antimicrobial Activity of New 5-Aryl-3-(2-hydroxyphenyl)-4,5-dihydro-1H-pyrazole-1-carboximidamides
This work aims the synthesis of amidino pyrazolines by the cyclocondensation reaction between 3-(hetero)aryl-1-(2-hydroxyphenyl)enones and aminoguanidine hydrochloride under sonochemical conditions. Thirteen new compounds were synthesized in 15-83% of yield after sonication for 30 min without purification by chromatography. Furthermore, antimicrobial activit
J. Braz. Chem. Soc.. Publicado em: 2020-04
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3. Oxone®-Promoted One-Pot Synthesis of 1-Aryl-4-(organylselanyl)-1H-pyrazoles
We describe herein an efficient protocol for the one-pot synthesis of 4-organylselanylpyrazoles by direct cyclocondensation and C-H bond selenylation reactions starting from hydrazines, 1,3-diketones and diorganyl diselenides promoted by Oxone®. The products were obtained through a metal catalyst free methodology, under mild conditions, in short reaction ti
J. Braz. Chem. Soc.. Publicado em: 21/10/2019
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4. Streamlined Synthesis of 6-((1H-1,2,3-Triazol-4-yl)methyl)-1H-pyrrolo [3,4-d]pyridazin-1-one System via Sequential N-Alkylation, CuAAC, and [4 + 2] Cyclization Reactions
An efficient sequential three-step reaction methodology for the synthesis of three new series-1-(prop-2-yn-1-yl)-1H-pyrroles, methyl 4-acetyl-1-((1H-1,2,3-triazol-4-yl)methyl)-1H-pyrrole-3-carboxylates and 6-((1H-1,2,3-triazol-4-yl)methyl)-2,6-dihydro-1H-pyrrolo[3,4-d]pyridazin-1-ones-is reported. The methodology comprises: (i) N-alkylation reactions of poly
J. Braz. Chem. Soc.. Publicado em: 23/05/2019
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5. Chiral Bistacrine Analogues: Synthesis, Cholinesterase Inhibitory Activity and a Molecular Modeling Approach
Cholinesterase enzymes are important targets for the therapy of Alzheimer’s disease. Tacrine-based dual binding site cholinesterases inhibitors are potential disease-modifying anti-Alzheimer drug candidates. In the present work, we described the synthesis of a series of chiral homo- and heterodimers of bis(7)-tacrine connected by a heptylene chain as a spa
J. Braz. Chem. Soc.. Publicado em: 2017-11
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6. Ultrasound-Promoted Synthesis of 3-(Thiophen-2-yl)-4,5-dihydro-1H-pyrazole-1-carboximidamides and Anticancer Activity Evaluation in Leukemia Cell Lines
3-(Thiophen-2-yl)-4,5-dihydro-1H-pyrazole-1-carboximidamides were efficiently prepared through a cyclocondensation of thiophenylchalcones with aminoguanidine hydrochloride under ultrasonic conditions in the presence of KOH and ethanol as a green solvent in short reaction times (15-35 min) and good yields (62-95%). All compounds produced were evaluated agains
J. Braz. Chem. Soc.. Publicado em: 2017-02
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7. Synthesis, Structure Elucidation, Antioxidant and Antimicrobial Activity of Novel 2-(5-Trifluoromethyl-1H-pyrazol-1-yl)-5-(5-trihalomethyl-1H-pyrazol-1-yl-1- carbonyl)pyridines
This paper describes an efficient approach for the synthesis of a novel series of sixteen 2-(5-trifluoromethyl-1H-pyrazol-1-yl)-5-(5-trihalomethyl-1H-pyrazol-1-yl-1-carbonyl) pyridines, for the first time with non-identical substituents in both pyrazole rings, through the cyclocondensation reaction of 4-methoxy-4-alkyl(aryl/heteroaryl-1,1,1-trihaloalk-3-en-2
J. Braz. Chem. Soc.. Publicado em: 2015-11
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8. Synthesis of 4-Arylselanylpyrazoles Through Cyclocondensation Reaction Using Glycerol as Solvent
We describe here a simple method to synthesize 4-arylselanylpyrazoles by reaction of α-arylselanyl-1,3-diketones with arylhydrazines using glycerol as solvent at 60 °C under N2 atmosphere. This is a direct cyclocondensation reaction performed with α-arylselanyl-1,3-diketones and arylhydrazines bearing electron-withdrawing and electron-donating groups a
J. Braz. Chem. Soc.. Publicado em: 2015-08
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9. Straightforward and Clean Ultrasound-Promoted Synthesis of 2-(4,5-Dihydro‑1H‑pyrazol-1-yl)pyrimidines
A series of twelve novel 2-(pyrazol-1-yl)pyrimidine derivatives was easily obtained under ultrasonic conditions by the cyclocondensation reaction of 1-carboxamidino-pyrazoles with 4-methoxyvinyl-trifluoromethyl ketones using ethanol as an environment-friendly solvent in the presence of potassium hydroxide. Comparison of the ultrasound-promoted reaction with
J. Braz. Chem. Soc.. Publicado em: 2015-06
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10. Síntese de 3-haloacetil-4-metilquinolinas utilizando líquido iônico sob irradiação de micro-ondas / Microwave-assisted synthesis of 3-haloacetyl-4- methylquinolines in ionic liquid
Neste trabalho é descrita a síntese de uma série de 3-haloacetil-4-metilquinolinas a partir da reação de ciclocondensação de 4-alcoxivinil cetonas [R1C(O)CH=C(R2)(OCH3), onde R1 = CF3, CCl3, CHCl2, CF2Cl, CF2CF3 e R2 = Me, Et, Pr, Bu, i-Bu, i-Pent] com 2-aminoacetofenona. As condições reacionais utilizadas para a obtenção dos compostos heterocícl
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 27/07/2011
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11. SÍNTESE DE 1-ARIL-4-[(DIMETILAMINO)METILENO] PIRROLIDINO-2,3,5-TRIONAS UTILIZANDO IRRADIAÇÃO DE MICRO-ONDAS / MICROWAVE-ASSISTED SYNTHESIS OF 1-ARYL-4 [(DIMETHYLAMINO) METHYLENE] PYRROLIDINE-2,3,5-TRIONE
A síntese de uma série de 4-(dimetilamino)metileno-1-aril-pirrolidino-2,3,5-triona foi realizada a partir da reação de ciclocondensação da b-enaminodicetona [Cl3C(O)C(=CHNMe2)C(O)CO2Et] com derivados da anilina [R = Ph, 3-Me-C6H4, 3- MeO-C6H4, 3-HO-C6H4, 4-Me-C6H4, 4-F-C6H4, 4-Cl-C6H4, 4-Br-C6H4, 4-O2N-C6H4, 4- MeCO-C6H4]. As condições reacionais uti
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 24/02/2011
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12. Simultaneous regioselective synthesis of trifluoromethyl-containing 1,7-phenanthrolines and quinolines from cyclocondensation reaction of N,N'-bis(oxotrifluoroalkenyl)-1,3-phenylenediamines
Este trabalho relata interessantes resultados relativos a síntese convencional de uma nova série de 2,10-dialquil(aril)-4,8-bis (trifluorometil)-1,7-fenantrolinas, em rendimentos de 22-40%, a partir das reações de ciclização de N,N'-bis(oxotrifluoralquenil)-1,3-fenilenodiaminas [1,3-C6H4-(NHCR=CHC(O)CF3)2] em um meio fortemente ácido (PPA) e na ausên
Journal of the Brazilian Chemical Society. Publicado em: 2011-08