Peroxynitric Acid: A Convenient Oxygen Source for Oxidation of Organic Compounds Catalyzed by Polyimide-Supported Manganese (III) Tetrakis(4-methoxylphenyl)porphyrin Acetate

Abstract

In this work, a polyimide (PI) containing triazole units was synthesized using 3,5-diamino-1,2,4-triazole and pyromellitic dianhydride in N-methyl-2-pyrrolidinone. This polymer was used as the support of manganese (III) tetrakis(4-methoxylphenyl)porphyrin acetate to attain a heterogeneous catalyst; namely Mn(T4-OMePP)OAc@PI. The synthesized PI and Mn(T4-OMePP)OAc@PI were characterized by different spectroscopic and analytical techniques. The resulted catalyst was applied for epoxidation of alkenes and dehydrogenation of Hantzsch 1,4-dihydropyridines (1,4-DHP) by peroxynitric acid (PNA; HOONO2) as a convenient new oxygen source. In association with HOONO2, Mn(T4-OMePP)OAc@PI was stable and proved to be an efficient, reusable and selective catalyst for epoxidation of alkenes (36-96% yield) and dehydrogenation of Hantzsch 1,4-DHP’s ( 94-100% yield).