Síntese, estrutura e cinética das reações de SNAr de aril-sidnonas

Abstract

The mesoíonic compounds aro heterocyclic which synthesis has shown interest mainly because of their potencial biologic activity and their participation in several reactions in which new heterocyclic compounds aro originated. Considering these factors, wo could synthetize and characterize five new mesoionic compounds of sydnones class: 3-N-[4-X-3-nitrophenyl]-l,2,3-oxadiazolum-5-olate, where X = chloro, pyrrolidino, pyperidino, morpholino, methoxi and cyclohexilamino. The structures of new mesoionic compounds were characterized by IR, UV, NMR 1H and 13C spectroscopy, and mass spectrometry. Quantitative studies of SNAr reactions with nucleophilus sodium methoxide, pyperidine and cyclohexilamine were performed using a 3-N-[4-vhloro-3-nitrophenyl]sydnone, as substrato, where the mesoionic ring was considered as a substitutive group. The rate coefficients of the reactions were determined in various temperatures and the activation parameters were calculated. It was verified that the activation parameters were in accordance to the used nucleophilic strength and with the exceptional character of the mesoionic ring as a substitutive. The solvent effect has also been studied, and the difference of the substrates behavior was verified in the supposed way, in the presence of methanol and N,N-dimethilformamide. The 3-N[4-X-3-nitrophenil]sydnones, where X = chloro, pyrrolidine, pyperidine and morpholine were tested against experimental tumors in mice. The chloro compounds and substituted pyrrolidine have showed significative inhibition of the tumors and increasing of the survival of the tested animais.