Two-dimensional nuclear magnetic resonance spectra of selected tricyclic antidepressants.

Two-dimensional nuclear magnetic resonance (2D NMR) spectroscopy has been used to assign 13C spectra of the tricyclic antidepressants imipramine and chlorimipramine . The 2DINADEQUATE method was used to unambiguously assign the aromatic spectral region for the former compound. Errors in previous literature assignments based on 1D methods were corrected. For chlorimipramine the pitfalls of classical substituent chemical shift arguments for 13C assignments and the difficulties of 1D selective 1H irradiation in overlapped systems are contrasted with the power and relative simplicity of the 2D-13C, 1H-correlated and 13C, 1H RELAY methods.