82706-88-5Relevant academic research and scientific papers
Effective Methods for the Syntheses of 2-Pyrazolines and Pyrazoles from Diazocarbonyl Compounds
Doyle, Michael P.,Colsman, Mark R.,Dorow, Roberta L.
, p. 943 - 946 (2007/10/02)
Dipolar addition of diazocarbonyl compounds to α,β-unsaturated esters and nitriles in the presence of pyridine results in the production 2-pyrazolines in nearly quantitative yields.In one case, reaction of α-diazoacetophenone with acrylonitrile, Michael addition of the 2-pyrazoline to the conjugated olefin is observed, but this process is minimized by limiting the amount of pyridine employed. 5-Cyano-2-pyrazolines are converted to derivative pyrazoles through alkoxide promoted hydrogen cyanide elimination.With vinyl sulfone, α-diazoacetophenone undergoes sequential dipolar addition, Michael addition, and vinyl sulfite elimination under exceptionally mild conditions to form the derivative β-(1-pyrazolyl)ethyl vinyl sulfone in good yield.
