New isomeric <i>N</i>‐substituted hydrazones of 2‐, 3‐ and 4‐pyridinecarboxaldehydes and methyl‐3‐pyridylketone

Abstract

Abstract Twelve compounds unknown in the literature N ‐( E )‐2‐stilbenyloxymethylenecarbonyl substituted hydrazones of 2‐, 3‐ and 4‐pyridinecarboxaldehydes, as well as methyl‐3‐pyridylketone have been prepared. The stereochemical behavior of these compounds in dimethyl‐d 6 sulfoxide solution has been studied by 1 H NMR technique. The E geometrical isomers and cis/trans amide conformers have been found for N ‐substituted hydrazones 1–12. EI induced mass spectral fragmentation of these compounds were also investigated. The data obtained create the basis for distinguishing isomers.