Síntese de maleimidas 3,4-substituídas a partir de derivados de tiazolidina-2,4- dionas

Abstract

In this work, a protocol for the preparation of 3,4-substituted maleimides, containing a -SCH3 group in the 3-position of the ring and aryl, heteroaryl or vinyl groups in the 4-position, was elaborated, including the novel compounds containing pyridyl groups. In addition to being a one-step process, this methodology stands out for applying the transition metal-free reaction conditions, through the use of DMSO as solvent and reagent, and microwave oven as a heating source. The substrates used were thiazolidine-2,4-dione, making it possible to explore their reaction possibilities, which went from a simple alkylation procedure to the surprising and valuable rearrangement reaching the maleimide product. Thus, using as optimized reaction conditions, a wide range of products was prepared with yields of up to 97%. Aiming to propose a plausible mechanism for this reaction, a series of control experiments were performed and strongly suggested that the rearrangement involves a key isocyanate intermediate as well as an additional reaction with in situ generated methylthiomethyl acetate.