Straightforward and Regiospecific Synthesis of Pyrazole-5-carboxylates from Unsymmetrical Enaminodiketones

Autor:	Fernanda A. Rosa, Marcos A. P. Martins, Pablo Machado, Helio G. Bonacorso, Nilo Zanatta, Pâmela S. Vargas
Rok vydání:	2008
Předmět:	Substitution reaction chemistry.chemical_compound chemistry Group (periodic table) Hydrochloride Organic Chemistry Regioselectivity Pyrazole Medicinal chemistry
Zdroj:	Synlett. 2008:1673-1678
ISSN:	1437-2096 0936-5214
Popis:	A series of 4-substituted 1 H-pyrazole-5-carboxylates was prepared from the cyclocondensation reaction of unsymmetrical enaminodiketones [RC(O)C(=CNMe 2 )C(O)CO 2 Et, where R = Ph, 4-MeOC 6 H 4 , 4-ClC 6 H 4 , 4-FC 6 H 4 , 4-O 2 NC 6 H 4 , thien-2-yl, benzofur-2-yl, CCl 3 and CF 3 ] 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)-1 H-pyrazole-4-carboxylic acid was synthesized from regiospecific conversion of ethyl 4-(2,2,2-trichloroacetyl)-1-(1,1-dimethylethyl)-1 H-pyrazole-5-carboxylate. The carbonyl substitution reaction was regiospecific for the trichloroacetyl group and did not affect the ester group.
Databáze:	OpenAIRE
Externí odkaz:	https://explore.openaire.eu/search/publication?articleId=doi_________::4172c010d8454c2e2968d2d3143ee4e8 https://doi.org/10.1055/s-2008-1078482 Zobrazit plný text záznamu