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DC Field | Value | Language |
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dc.rights.license | restrictedAccess | - |
dc.contributor.author | Markovic, Svetlana | - |
dc.contributor.author | Joksović, Milan | - |
dc.contributor.author | Bombicz P. | - |
dc.contributor.author | Leovac V. | - |
dc.contributor.author | Marković, Violeta | - |
dc.contributor.author | Joksović, Ljubinka | - |
dc.date.accessioned | 2021-04-20T15:05:58Z | - |
dc.date.available | 2021-04-20T15:05:58Z | - |
dc.date.issued | 2010 | - |
dc.identifier.issn | 0040-4020 | - |
dc.identifier.uri | https://scidar.kg.ac.rs/handle/123456789/10185 | - |
dc.description.abstract | The structure of 5-hydroxy-3,5-dimethyl-1-S-methylisothiocarbamoyl-2- pyrazolinium iodide (HDMCPI), a cyclic intermediate for a 3-aminopyrazole derivative, was determined by means of X-ray analysis and spectroscopic techniques. In a treatment of HDMCPI in alkaline aqueous solution, 4-acetyl-3(5)-amino-5(3)-methylpyrazole (AAMP) was unexpectedly yielded. The reaction of HDMCPI was monitored by 1H and 13C NMR spectroscopy. It was shown that keto-imine tautomer appears as the only tautomeric form. Density functional theory explained the spontaneous formation of keto-imine tautomer, whose existence is the main condition for generating a carbanion in alkaline medium. The carbanion further undergoes cyclization and elimination of MeSH, thus yielding AAMP. In the reaction of acetylacetone with thiosemicarbazide instead of S-methylisothiosemicarbazide, there were no traces of AAMP. This result can be attributed to the absence of keto-imine form in the tautomeric equilibrium, which would provide the formation of a carbanion for a nucleophilic attack and further cyclization. © 2010 Elsevier Ltd. All rights reserved. | - |
dc.rights | info:eu-repo/semantics/restrictedAccess | - |
dc.source | Tetrahedron | - |
dc.title | Theoretical study on structural and mechanistic aspects of synthesis of a 3-aminopyrazole derivative | - |
dc.type | article | - |
dc.identifier.doi | 10.1016/j.tet.2010.05.093 | - |
dc.identifier.scopus | 2-s2.0-77955424413 | - |
Appears in Collections: | Faculty of Science, Kragujevac |
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