Application Of Nitroalkene Derivatives In Constructing Nitrogen-or Sulfur-Containing Heterocycles

Nitroalkene is a hot research area in organic chemistry during recent years because of its unique reaction sites and special chemical properties. As a synthon, it can participate in many organic reactions. The nitroalkene is highly polarized because of the strong electron-withdrawing property of nitro group and it can react with a variety of electrophiles easily. The nitrogen- or sulfur-containing heterocyclic compounds are usually used as structural units in pharmaceuticals and pesticides because of their unique biological activity, high absorption and low toxicity. Furthermore, the heterocyclic compounds which contain pyridine and thiazole are particularly widely used in medicines and pesticides. In this dissertation, the application of nitroalkenes as an organic synthon for access of nitrogen-and sulfur-containing heterocycles was investigated. The kinds of novel heterocycles, that is, dihydropyridine-fused 1,3-diaza heterocycle,1,4,2-dithiazolidin heterocyclic and 1, 3-thiazetidins were efficient constructed.1. The Knoevenagel adducts formed by phthalic anhydride and ethyl cyanacetate reacted with heterocyclic ketene aminals affording the novel 2-oxo-1,2-dihydropyridine-fused 1,3-diaza heterocycles. The reaction conditions were optimized and fifteen 2-oxo-1, 2-dihydropyridine-fused 1,3-diaza heterocycles were synthesized under the optical conditions.2. The reactions of thiourea derivatives with 1, 1-dichloro-2-nitroethene were studied and the two unreported heterocycles 1,4,2-dithiazolidin heterocyclic analogues and 1, 3-thiazetidin heterocycles were discovered. These two kinds of nitrogen- and sulfur-containing heterocyclic have not been reported elsewhere. The optimizing reaction conditions were explored. The types of products have strong solvents dependency.1,4, 2-Dithiazolidins were formed in aprotic solvent chloroform, while in ethanol 1,3-thiazetidins were the main products. And the region-selective of the unsymmetrical thioureas were explored. The total of 22 nitro- and sulfur-containing heterocycles were synthesized and their biological activity and application are in further exploration.