Chemistry of the phenoxathiins and isosterically related heterocycles. XX. Assignment of the 13C‐NMR spectra of phenarsazine‐10‐chloride and several substituted analogs. The effect of substitution on the anisotropic reorientation of the phenarsazine system

The total assignment of the 13C‐nmr spectra of phenarsazine‐10‐chloride and several substituted analogs is reported. Spin‐lattice (T1) relaxation measurements have shown these systems to reorient anisotropically. In the case of the parent system and the 3‐chloro substituted system, the axis of anisotropic reorientation has been shown to pass approximately through the center of the molecule. In the case of benzo[c]phenarsazine‐7‐chloride, the axis of anisotropic reorientation, which has been accurately defined, is shifted 23° from that in the previous cases, the shift occurring in the direction of the benzo‐moiety.