Abstract
Natural abundance 17O NMR data for 14 substituted methyl N-arylcarbamates obtained in acetonitrile solution at 75°C are reported. The 17O NMR chemical shifts of hindered ortho N-arylcarbamates are shielded relative to unhindered ones; a quantitative relationship is observed between the carbonyl 17O NMR chemical shifts and molecular mechanics (MM2) predicted torsion angles. The carbonyl 17O NMR chemical shifts of meta and para substituted N-arylcarbamates are correlated with Hammett sigma constants.