Study On The Synthesis Of Five-membered N-heterocyclic Compounds Containing Potential Biological Activity

In recent years, with the rapid development of life sciences, natural products of nitrogen heterocyclic compounds have attracted considerable attention. Scientists have discovered that biologically active macromolecules, proteins, enzymes and nucleic acids are nitrogenous compounds, many natural products such as alkaloids, vitamins and antibiotics are also mostly N-heterocyclic compounds. Since 1828, German chemists Wohler Friedrich (1800-1882) synthesized successfully the first nitrogenous organic compound - urea, synthetic nitrogen-containing compounds have had a completely new situation the field of organic chemistry. So far, there have been developed many biologically active nitrogen containing compounds, the development and usefulness makes the nitrogen compounds with a wide range of applications not only in pharmaceuticals, herbicides, insecticides, fungicides and so on, but also in dye, multi-functional materials and many other areas.1. Benzimidazole-chalcone, isatin reacted with amino acids to form a series novel spiroheterocyclic pyrrolidine compounds which has not been reported by according the reaction of 1, 3-dipolar cycloaddition. The reaction is smoothy and efficient in wide range of application and various substituents were applicable. All compounds were characterized by 1HNMR, IR spectra and a single crystal structure was determined by X-ray diffraction method.2. A series of N-heterocyclic carbene precursor salt were first synthesized. The catalytic activity of these carbenes were test by benzoin condensation reaction, resulting that water was the best solvent and benzimidazole bromide 5b was the best catalyst and triethylamine was the best base regent. In microwave condition the benzoin-type compounds could be highly obtained. We also found that not any other catalysts needed but only air was used as the oxidant, the desired benzil derivatives can be synthesized in high yield. All compounds were characterized by 1HNMR, IR spectra.3. Two-step one-pot synthesis of poly-substituted imidazole compounds from aromatic aldehydes ammonium acetate (aromatic amines) was developed using the benzimidazole salt as the catalysts under microwave irradiation. The intermediate products needed no any more separation, the starting materials were cheap and the reaction process was fast, efficient, and environmentally friendly, consistent with the concept of green chemistry. All compounds were characterized by 1HNMR, IR spectra and a single crystal structure was determined by X-ray diffraction method.