PMR spectfa of alkyl-substituted δ1-pyrazolines

Data from the PMR spectra of ¹-pyrazollnes and their acyclic analogs — azo compounds — were compared. It is shown that the difference in the chemical shifts of similar fragments in these compounds is due to the peculiarities of the three-dimensional structures, which lead to different contributions to shielding from the unshared electron pairs of nitrogen and the magnetically anisotropic N=N bond.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 987–989, July, 1974.