Preparation and properties of azinium salts of the 2-pyrazoline series

Azinium salts containing pyrazoline fragments have been obtained by the reaction of 2-pyrazolines with aromatic and heteroaromatic aldehydes, acetylacetone, and acetoacetic ester in the presence of H₂SnCl₅ and HBF₄. Reactions of nucleophilic addition to the multiple bonds and also some cycloaddition reactions among the arylidene derivative have been studied. From the azinium salts of a series of -dicarbonyl compounds have been obtained previously unknown enamino carbonyl compounds of the 2-pyrazoline series.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 101–105, January, 1984.