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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

Green Synthetic Methodology of (E)-2-cyano-3-aryl Selective Knoevenagel Adducts Under Microwave Irradiation

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Quintero Jimenez, David Esteban [1, 2] ; Zanin, Lucas Lima [1] ; Diniz, Luan Farinelli [3] ; Ellena, Javier [3] ; Meleiro Porto, Andre Luiz [1]
Total Authors: 5
[1] Univ Sao Paulo, Lab Quim Organ & Biocatalise, Inst Quim Sao Carlos, Av Joao Dagnone 1100, BR-13563120 Sao Carlos, SP - Brazil
[2] Univ Fed Amapa, Rodovia Juscelino Kubitscheck, KM 02 S-N, BR-68903419 Macapa, Amapa - Brazil
[3] Univ Sao Paulo, Lab Multiusuario Cristalog Estrutural, Inst Fis Sao Carlos, Av Trabalhador Sao Carlense 400, BR-13566590 Sao Carlos, SP - Brazil
Total Affiliations: 3
Document type: Journal article
Source: CURRENT MICROWAVE CHEMISTRY; v. 6, n. 1, p. 54-60, 2019.
Web of Science Citations: 0

Background: The Knoevenagel condensation is an important reaction in organic chemistry because of its capacity to form new C-C bonds and its products are mainly used in organic synthesis as intermediates, due to the large number of reactions they can undergo. Based on the importance of the Knoevenagel adducts, a sustainable synthetic methodology was developed employing microwave irradiation. Objective: Develop a synthetic methodology employing microwave irradiation and green solvents to obtain Knoevenagel adducts with high yields. Methods: Knoevenagel condensation reactions were evaluated with different basic catalysts, as well as in the presence or absence of microwave irradiation. The scope of the reaction was expanded using different aldehydes, cyanoacetamide or methyl cyanoacetate. The geometry of the formed products was also evaluated. Results: After the optimization process, the reactions between aldehydes and cyanoacetamide were performed with triethylamine as catalyst, in the presence of microwave irradiation, in 35 minutes, using NaCl solution as solvent and resulted in high yields 90-99%. The reactions performed between aldehydes and methyl cyanoacetate were also performed under these conditions, but showed better yields with EtOH as solvent 70-90%. Finally, from X-ray analysis, the (E)-geometry of these compounds was confirmed. Conclusion: In this study we developed synthetic methodology of Knoevenagel condensation using triethylamine, green solvents and microwave irradiation. In 35 minutes, products with high yields (70-99%) were obtained and the (E)-geometry of the adducts was confirmed. (AU)

FAPESP's process: 14/18257-0 - New approaches in biocatalytic reactions
Grantee:Andre Luiz Meleiro Porto
Support type: Regular Research Grants
FAPESP's process: 16/20155-7 - Biocatalytic reactions of aminolysis and kinetic resolution by lipases and biodegradation of agrochemicals by microorganisms
Grantee:Andre Luiz Meleiro Porto
Support type: Regular Research Grants