Synthesis and nuclear magnetic resonance spectroscopic studies of 1‐arylpyrroles

Abstract

Abstract A series of m ‐ and p ‐substituted 1‐phenyl, 1‐benzyl, 1‐benzoyl, and 1‐(2‐phenylethyl)pyrroles was prepared and their 1 H and 13 C nmr spectroscopic characteristics were examined. In general, good correlations were observed between the chemical shift values of the βH and the βC of pyrroles [except 1‐(2‐phenylethyl)pyrroles] and the Hammettt σ. The observation may be explained in terms of the electronic effects of the substituents which are transmitted through bonds and through space by interaction of the p orbitals between βCs of the pyrrole ring and m ‐ and p Cs of the phenyl ring. Substituent constants of 1‐pyrrolyl, 1‐pyrrolylmethyl, and 1‐pyrroloyl groups for the 1 H and 13 C chemical shifts of phenyl ring are also presented.