SÍNTESE DE HETEROCICLOS VIA REAÇÕES DE CICLOCONDENSAÇÃO DE a-ETILOXALIL E -PIRAZOLIL(ALQUIL) b-DIMETILAMINOENONAS COM 1,2- OU 1,3-DINUCLEÓFILOS / SYNTHESIS OF HETEROCYCLES VIA CYCLOCONDENSATION REACTIONS OF a-ETHYLOXALYL AND -PYRAZOLYL(ALKYL) b-DIMETHYLAMINOENONES WITH 1,2- OR 1,3-DINUCLEOPHILES

AUTOR(ES)
DATA DE PUBLICAÇÃO

2009

RESUMO

Chemoselective synthesis of ethyl 4-pirimidinecarboxylates and/or ethyl 5-pirimidineoxalates via cyclocondensation reaction of b-dimethylaminoenones [R1C(=O)C(=CNMe2)C(=O)CO2Et, where R1 = Ph, 4-MeC6H4, 4-MeOC6H4, 4-BrC6H4, 4-ClC6H4, 4-FC6H4, 4-O2NC6H4, 2-thienyl, benzo[b]furan-2-yl and CF3] with NCN 1,3- dinucleophiles such as benzamidine hydrochloride or 1H-1-pyrazolyl-carboxamidine hydrochloride (50-86%); utilization of ethyl 4-pirimidinecarboxylates (when R1 = Ph, 4-MeOC6H4, 4-FC6H4 and 2-thienyl) in the cyclization reaction with hydrazine monohydrate, leading to 7,8-dihydropyrimido[4,5-d]pyridazin-8-ones (81-92%). In this work it was also studied the condensation reaction of (3,5-dimethyl-1H-1- pyrazolyl)alkylketones with N,N-dimethylformamide dimethylacetal, with the aim to obtain b-dimethylaminoenones [PhC(=O)C(=CNMe2)(3,5-dimethyl-1H-1-pyrazolyl), PhC(=O)C(=CNMe2)(3,5-dimethyl-1H-1-pyrazolylmethyl) and MeC(=O)C(=CNMe2)(3,5-dimethyl-1H-1-pyrazolyl)] (92-98%); and synthesis of 1,4-biazoles via cyclocondensation reaction of b-dimethylaminoenones with different 1,2-dinucleophiles such as hydrazine monohydrate, terc-butylhydrazine hydrochloride,phenylhydrazine hydrochloride, carboxymethylhydrazine or hydroxylamine hydrochloride (50-80%). The X-ray diffraction technique was used in the elucidation of the stereochemistry of PhC(=O)C(=CNMe2)(3,5-dimethyl-1H-1-pyrazolylmethyl) and regiochemistry of the cyclocondensation reactions.

ASSUNTO(S)

quimica enaminones enaminonas heterociclos pirimidinas heterocycles biazóis chemoselectivity quimiosseletividade biazoles pyrimidines

ACESSO AO ARTIGO

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