Chemistry of the phenoxathiins and isosterically related heterocycles. XIV. Total assignment of the 13C‐Nmr spectrum of pyrrolo[3,2,1‐kl]phenothiazine

Total assignment of the 13C‐nmr spectrum of the novel tetracyclic phenothiazine, pyrrolo[3,2,1‐kl]phenothiazine is described. Assignments were determined from model systems, 1H‐13C spin‐coupling behavior in conjunction with selective excitation techniques and spin‐lattice (T1) relaxation measurements. The anisotropic reorientation of this ring system via a principal axis passing through the center of the molecule, which provides a qualitative basis for signal discrimination, is also discussed.