N.M.R. spectra of the carbolines. I. Spectral parameters

Abstract

The N.M.R. spectra of carbazole and the four isomeric azacarbazoles, α-, β-, γ-, δ-carboline, have been studied in dimethyl sulphoxide and acetone and, where possible, in tetrahydrofuran and chloroform. Spin decoupling and n.O.e. experiments have been used to aid in the assignment of the spectra and to determine the relative signs of coupling constants. The spectra have been fully analysed and the trends in the values of the spectral parameters for this series of related molecules are discussed. In two of these compounds small couplings across the tertiary nitrogen atoms, similar to that observed in pyridine, were found.