Deep eutectic solvent mediated synthesis of thiomethyltriazolo[1,5- a ]pyrimidines
| Autor: | Guilherme C. Paveglio, Alexandre R. Meyer, Leticia V. Rodrigues, Dayse N. Moreira, Nilo Zanatta, Helio G. Bonacorso, Taiana S. Munchen, Paola A. Melo, Marcos A. P. Martins, Sindy R. Krzyzaniak, Clarissa P. Frizzo |
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| Rok vydání: | 2016 |
| Předmět: |
chemistry.chemical_classification
Base (chemistry) 010405 organic chemistry Chemistry Regioselectivity 010402 general chemistry Condensed Matter Physics 01 natural sciences Medicinal chemistry Atomic and Molecular Physics and Optics 0104 chemical sciences Electronic Optical and Magnetic Materials Catalysis Deep eutectic solvent chemistry.chemical_compound Ionic liquid Materials Chemistry Organic chemistry Organic synthesis Physical and Theoretical Chemistry Spectroscopy Conjugate Choline chloride |
| Zdroj: | Journal of Molecular Liquids. 223:934-938 |
| ISSN: | 0167-7322 |
| DOI: | 10.1016/j.molliq.2016.08.031 |
| Popis: | Molecular solvents, ionic liquids, and choline chloride-based DES were evaluated for the synthesis of a methylthiotriazolo[1,5-a]pyrimidines series via the cyclocondensation reaction between 4-dimethylamino-1-aryl-3-alken-2-ones (RC(O)CH = CHNMe2, in which R = C6H5, 4-Me-C6H4, 4-OMe-C6H4, 4-F-C6H4, 4-Br-C6H4, 4-I-C6H4, Fur-2-yl, and Thien-2-yl) and 3-amino-5-methylthio-1H-1,2,4-triazole. The best result was obtained using ChCl with TsOH at a ratio of 1:2, and it drastically reduced the reaction time from 1.5 h to 5 min, with high regioselectivity and good yields (82–98%). Quantum chemical calculations helped to show the mechanism for high regioselectivity of the reaction. Up until now, ChCl:TsOH (1:2) has not been completely characterized and used as a catalyst in organic synthesis. Thus, it was fully characterized by NMR, DSC, TGA, and ICP-AES. The results showed that ChCl:TsOH (1:2) presents two forms that can act as catalyst: acid form (17%) and its conjugate base (83%). |
| Databáze: | OpenAIRE |
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