Молимо вас користите овај идентификатор за цитирање или овај линк до ове ставке:
https://scidar.kg.ac.rs/handle/123456789/10185
Назив: | Theoretical study on structural and mechanistic aspects of synthesis of a 3-aminopyrazole derivative |
Аутори: | Markovic, Svetlana Joksović, Milan Bombicz P. Leovac V. Marković, Violeta Joksović, Ljubinka |
Датум издавања: | 2010 |
Сажетак: | 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. |
URI: | https://scidar.kg.ac.rs/handle/123456789/10185 |
Тип: | article |
DOI: | 10.1016/j.tet.2010.05.093 |
ISSN: | 0040-4020 |
SCOPUS: | 2-s2.0-77955424413 |
Налази се у колекцијама: | Faculty of Science, Kragujevac |
Датотеке у овој ставци:
Датотека | Опис | Величина | Формат | |
---|---|---|---|---|
PaperMissing.pdf Ограничен приступ | 29.86 kB | Adobe PDF | Погледајте |
Ставке на SCIDAR-у су заштићене ауторским правима, са свим правима задржаним, осим ако није другачије назначено.