Synthesis of Pyrrole2, 3-dPyridazine Derivatives Under Ultrasound Irradiation

In the report, taken β keto acid esters as the starting material, five compounds of pyrrole aldehydes were synthetized by nitrosation, Knorr condensation and oxidation with ammonium ceric nitrate. Under ultrasound irradiation(40Hz, 200W), five pyrrole2, 3-dpyridazine compounds were synthesized by the reaction of pyrrole aldehydes and hydrazine hydrates.All the compounds were characterized by m.p., TLC, IR and¹H-NMR.Compared with the conventional synthesis of pyrrole2, 3-dpyridazine compounds, the current progress indicates that the preparation of pyrrole2, 3-dpyridazine compounds through pyrrole aldehydes and hydrazine hydrate under ultrasound irradiation, has advantages of simple operation, low energy consumption and high efficiency of synthesis. After verification, two compounds of pyrrole aldehydes (2d-2e) and four compounds of pyrrole alcohols (3a，3c-3e) are new compounds.