The Research Of Enzymatic Synthesis Of5-membered N-Heterocyclic Compounds

Most5-membered N-Heterocyclic compounds have certain pharmacological activity and biological activity, they can be used as medicine, and other fine chemical intermediates, to design and discover new methods to synthetize heterocyclic compounds are of great importance. Recently, enzymatic synthesis has received much attention in organic chemistry for synthesizing heterocyclic compounds for its high catalytic activities.Novel and efficient methods to synthetize pyrrole, imidazole,2-substituted of benzimidazole and pyrazole and [3,4-b] pyridine catalyzed by enzyme are rported.Part1:A novel method of synthesizing N-substituted pyrroles catalyzed by a-amylase from hog pancreas via Paal-Knorr reaction under mild conditions and the products were obtained with good to excellent yields (60-99%) was developed. The influences of reaction conditions including solvents, enzyme amount and temperature were investigated. And we obtained19N-substituted pyrroles.Part2:A simple and eco-friendly protocol for the synthesis of2,4,5-trisubstituted imidazoles has been described using lipase as a novel catalyst under mild conditions. We optimized the influences of reaction conditions including solvents, enzyme amount and temperature.9imidazole derivatives were synthesized with good yields.Part3:An efficient procedure of chemoselective synthesizing2-substituted benzimidazoles catalyzed by lipase from porcine pancreas (PPL) has been developed. And17benzimidazole derivatives were obtained. This method with mild conditions, excellent yields, and provides a new method for synthesizing2-substituted benzimidazoles derivatives.Part4:An efficient procedure of synthesizing pyrazolo [3,4-b] pyridines catalyzed by lipase has been developed. This method provides a new method for synthetic pyrazolo [3.4-b] pyridine derivatives under mild conditions with excellent yields, and10compounds were obtained.In summary, this paper provides the methods of enzymatic synthesis of 5-membered N-heterocyclic compounds, we obtained55compounds. All these products were characterized by1H NMR, IR, MS.