LONG RANGE PROTON-PROTON COUPLING IN SUBSTITUTED ANISOLES

The long range coupling, J1r, between the OMe methyl protons and the ortho ring proton has been determined in a series of substituted anisoles. Although this 5-bond coupling is present in all the anisoles, its magnitude is enhanced by the presence of a bulky substituent (Cl, Br, I and NO2) ortho to the methoxy group. The results have been interpreted in terms of restricted rotation, the larger value of J1r being associated with that conformation in which the OMe group is anti" to the ortho substituent. © 1969."