H-1 dynamic nuclear magnetic-resonance study of hindered rotations in N-aryl-N-benzyl alkyl carbanamates

The NMR variable temperature behaviour of a series of N‐aryl‐N‐benzyl alkyl carbamates was investigated. The barrier to rotation about the N‐aryl bond was determined for all the compounds studied. The values obtained, which are in good agreement with those found for structurally related N‐aryl‐N‐benzylamides, are in the range ΔG≠ = 60.7‐89.6kJ mol−1. For some carbamates another conformational phenomenon has been observed, namely the hindered rotation about the carbonyl carbon–nitrogen bond, with a barrier to rotation corresponding to reported values for similar systems.