MAGNETIC ANISOTROPY AND INTERPRETATION OF NMR SPECTRA OF LACTAMS .2. N-SUBSTITUTED PYRROLIDONES

The NMR spectra of a number of N-substituted pyrrolidones have been measured, and the cause of the magnetic non-equivalence of the methylene protons in the substituent side chain has been examined. In contrast to the previous lactams examined, this non-equivalence is not attenuated by the shielding effect of the side chain phenyl or the ring keto-group but is due purely to the asymmetric centre in the side chain. The chemical shifts of the lactam ring protons have been found to vary widely with substituent and this effect has also been investigated. © 1969.