Oxidation of phenol, cychohexanol and hydroquinone has been screened in the presence of copper(II) complexes with Schiff base Salen ligand, 1,5-bis{[(1E)-(2-hydroxyphenyl)methylene]amino}-1H-imidazole-4-carbonitrile, and encapsulated in the zeolite NaY using two different methods (A and B). The new heterogeneous catalysts were characterized by SEM, XRD, FTIR, EPR, Raman and chemical analysis. The structure of t...
A simple and general “one pot” procedure for the synthesis of 2,9-diarylpurines with one or multiple hydroxyl groups in the 2- aryl unit is described, from the reaction of 5-amino-4-amidinoimidazoles with phenolic aldehydes.
A forma como a ciência é ensinada nas escolas afecta profundamente a percepção que os estudantes têm do mundo que os rodeia e consequentemente a escolha de uma futura carreira nas ciências. Por outro lado, a abertura da escola à comunidade envolvente, proporciona as condições para a sua participação activa na vida escolar, assim como a promoção do sucesso escolar, através da formação integral dos alunos, dotand...
Two different approaches have been used for the synthesis of 6-enaminopurines 6 from 5-amino-4-cyanoformimidoyl imidazoles 1. In the first approach imidazoles 1 were reacted with ethoxymethylenemalononitrile or ethoxymethylenecyanoacetate under mild experimental conditions and this led to 9-substituted-6-(1-amino-2,2-dicyanovinyl) purines 6a-f or 9-substituted-6-(1-amino-2-cyano-2-methoxycarbonylvinyl) purines ...
An extremely simple method for the selective synthesis of 9-aryl and 9-alkyl 6-alkoxy or 6-alkoxyformimidoyl purines from the corresponding 6-cyanopurines is described. The reaction is carried out with methanol or ethanol in the presence of DBU. At room temperature, nucleophilic attack by the primary alcohol occurs selectively on the cyano carbon atom, leading to 6-alkoxyformimidoyl purines in good yields. Heat...
Financiadores do RCAAP | |||||||
![]() |
![]() |
![]() |
![]() |
![]() |
![]() |