Carbon‐13 chemical shifts in some 1‐substituted 5‐imino‐3‐phenyl‐4‐thioxo‐2‐imidazolidinones and related compounds

The cmr spectra of the title compounds have been obtained and the resonances assigned by classical means. Coupling of the imino proton to C‐5 is observed to be smaller than that to C‐4. A very large downfield shift due to substitution of a carbonyl sulfur at C‐4 is observed. The nmr assignments are shown to be self‐consistent throughout the series.