Síntese de novos fosforamidatos derivados de bases de Schiff

Abstract

The phosphoramidates are phosphoramidic acid derivatives having at least one -PNR1R2 group, where R1 and R2 are alkyl or aryl groups. These compounds are extensively studied due to their potential applications, such as antitumor, antileishmanial and antiurease. Another important group of organic compounds is Schiff bases, also known as imines or azomethine. Schiff bases (C=N) are potent biological agents and their associations with other molecular groups also recognized biological activities can generate a new concept of products with pharmacological actions. Exploring the potential presented by these two classes of compounds, this study aimed to synthesize new phosphoramidates derived from Schiff bases. Three novel intermediates aminoaryl phosphoramidates (87a-c) were obtained by phosphorylation reaction of phenylenediamine with dibutyl phosphite in a solid-liquid biphasic system, using hexachloroethane, potassium carbonate, tetrabutylammonium bromide and dichloromethane. The methodology developed solids in yields ranging from 68% to 90%. The infrared spectroscopic analysis and nuclear magnetic resonance confirmed the monophosphorylated derivative of o-, m-, and pphenylenediamine. The derivative 87c, however, proved to be contaminated with some impurity or by-product, so it is necessary to better assess its purification process. The coupling reaction between the intermediate 87b and benzaldehyde occurred according to the classical methodology for the formation of imines, resulting in a yellowish solid in 47% yield. The preliminary characterization data in the infrared indicated the presence of organophosphate and imine groups. The results of nuclear magnetic resonance, however, were inconclusive.