1070872-85-3Relevant academic research and scientific papers
Straightforward and regiospecific synthesis of pyrazole-5-carboxylates from unsymmetrical enaminodiketones
Rosa, Fernanda A.,Machado, Pablo,Vargas, Pamela S.,Bonacorso, Helio G.,Zanatta, Nilo,Martins, Marcos A. P.
experimental part, p. 1673 - 1678 (2009/04/07)
A series of 4-substituted 1H-pyrazole-5-carboxylates was prepared from the cyclocondensation reaction of unsymmetrical enaminodiketones [RC(O)C(=CNMe 2)C(O)CO2Et, where R = Ph, 4-MeOC6H 4, 4-ClC6H4, 4-FC6H4, 4-O2NC6H4, thien-2-yl, benzofur-2-yl, CCl 3 and CF3] with tert-butylhydrazine hydrochloride or carboxymethylhydrazine. The compounds were obtained regiospecifically and in good to excellent yields (73-94%). In addition, 5-carboxyethyl-1-(1,1- dimethylethyl)-1H-pyrazole-4-carboxylic acid was synthesized from regiospecific conversion of ethyl 4-(2,2,2-trichloroacetyl)-1-(1,1-dimethylethyl)- 1H-pyrazole-5-carboxylate. The carbonyl substitution reaction was regiospecific for the trichloroacetyl group and did not affect the ester group. Thieme Stuttgart.
