Structure and properties of 1-acylpyrazolines

Proton magnetic resonance spectroscopy and the method of dipole moments demonstrated that 1-acylpyrazolines exist primarily in the s-trans form, which is stabilized by the repulsion of like-charged nitrogen and oxygen atoms. Simultaneous reduction of the C =O and C =N bonds was observed during the action of lithium aluminum hydride on 1-formyl-and 1-trifluoroacetylpyrazolines, which is explained by the relatively high polarity of the C=N bond.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 488–491, April, 1972.