Studies on ¹³C Magnetic Resonance Spectroscopy. XIII. ¹³C and ¹H NMR of 4-Substituted Pyridazine and 2-Substituted Pyrazine Derivatives

Abstract

^<13>C chemical shifts of 4-substituted pyridazines and 2-substituted pyrazines, together with ¹H chemical shifts of the former compounds were measured. Linear correlations of the ¹³C and ¹H chemical shifts of 4-substituted pyridazines with those of monosubstituted benzenes and monosubstituted pyridines and with substituent constants σ_π were found. In addition, similar trends were noted for 2-substituted pyrazines. Chemical shifts of pyridazines and pyrazines can be predicted on the basis of these relationships.