Synthesis of some derivatives of compounds β-aminoketonic through Mannich reaction by usingbiocatalysts

Abstract

The Mannich reaction is one of the most widely used reactions in organic chemistry, and also one of the first examples of a multicomponent reaction already described on the literature. This reaction results in β-aminocarbonylated compounds which allow the generation of several structures that can be used in the synthesis of both biologically active molecules, and natural products, however, just a few synthetic routes resulting in the formation of β-aminocarbonylated compound are known. In this sense, new methodologies have been developed by involving new catalysts or chiral auxiliaries in the synthesis of β-aminocarbonylated compounds with biological activity. One of these methodologies is the biocatalysis, which is a technique that uses biological catalysts, like enzymes or micro-organisms to convert a substrate in a limited number of enzymatic steps. The use of micro-organisms, plants or isolated enzymes as chiral catalysts has proportioned a significant advance in the synthetic chemistry, because it is known that the biocatalysts have selective catalytic sites that afford the formation of enantiomerically pure products and which is extremely important, because it is known that differences of the chirality may have tragic or spectacular effects in humans. Concerning to the environmental issue, the biocatalysis is placed within the context of a new philosophy called Green Chemistry. However, in the State of Mato Grosso do Sul the researches involving this issue of biocatalysis are still incipient once that by the year of 2010 there was only one research group focused on this themeregistered in the Lattes Platform in the State. Because of the need of support to the researches focused on this issue in the State of Mato Grosso do Sul and to evaluate thebiocatalytic potential of different lineage of microorganisms and enzymes in the synthesis of compounds β-aminoketonic through Mannich reaction it was proposed the use of someenzymes such as: lipase, Lipozyme® and chymosin. The reactions were kept under stirring at room temperature from 24 to 48 hours in those which the enzymes were usedlike catalysts. All the reactions were monitored by thin layer chromatography. The crude of the reaction was purified on a silica gel column (70-230 mesh) and the obtained compounds were characterized by infrared spectroscopy, gas chromatography and nuclear magnetic resonance. All the reactions biocatalyzed by enzymes showed biocatalytic potential, but their concentration, the basicity of the amine and the reaction medium interfered in the reaction yield. The both three enzymes presented a higher affinity as for the less polar solvents (THF) as for the higher polar solvents(DMSO). However it was proposed the introduction of new low cost biocatalysts and environmentally safe on Mannich reactions.

Keywords

• mannich
• biocatalysts
• biocatalysis