Desenvolvimento de novos catalisadores para reações de acomplamento cruzado e monitoramento por espectrometria de massas com ionização por eletrospray

Abstract

In this work we synthesized three hydroxylated aromatic bis-imines with yields between 70 and 90% from the condensation of ortho hydroxy benzaldehydes with phenylenediamines or between isophthalaldehyde with ortho aminophenol. The bis-imines were transformed in the respective hydrogenated analogs, with yields between 75 and 89% using sodium borohydride and cerium chloride. Also were also synthesized two ionic bis-imines from the condensation of ortho-hydroxy benzaldehyde, functionalized with N-methylimidazolium, and ortho phenylenediamine. From these eight compounds (bis-imines and bis-amines) were synthesized eight palladium complexes with yields between 57 and 88%, six of them unpublished in literature. Subsequently, all palladium complexes were evaluated as catalysts in the Heck reaction between styrene and bromobenzene or iodobenzene / bromobenzene and methyl / ethyl acrylate. The best conditions were optimized, varying the type and amount of complex, solvent, type of base and reaction time. This study provided the E-stilbene and E-methyl/ethyl cinnamate in good yields by analysis by gas chromatography coupled to mass spectrometry (GC-MS), showing the viability of these complexes as catalysts for Heck reaction. The last part of this study consisted in investigation of these reactions by mass spectrometry with electrospray ionization (ESI-MS), in order to evaluate the participation of the complex in the reaction, however, this step did not provide good results.