Straightforward and Regiospecific Synthesis of Pyrazole-5-carboxylates from Unsymmetrical Enaminodiketones
Fernanda A. Rosa, Pablo Machado, Pâmela S. Vargas, Helio G. Bonacorso, Nilo Zanatta, Marcos A. P. Martins*
*Núcleo de Química de Heterociclos (NUQUIMHE), Departamento de Química, Universidade Federal de Santa Maria, 97.105-900 Santa Maria, RS, Brazil, Email: mmartinsbase.ufsm.br
F. A. Rosa, P. Machado, P. S. Vargas, H. G. Bonacorso, N. Zanatta, M. A. P. Martins, Synlett, 2008, 1673-1678.
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A series of 4-substituted 1H-pyrazole-5-carboxylates was prepared from the cyclocondensation reaction of unsymmetrical enaminodiketones with tert-butylhydrazine hydrochloride or carboxymethylhydrazine. The compounds were obtained regiospecifically and in very good yields.
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enones, cyclizations, regioselectivity, pyrazoles, heterocycles