Proton NMR data for a number of 1-X-4-Y-3,5-dimethylbenzenes and 1-X-2-Y-4-Z-3,5-dimethylbenzenes are presented. The proton chemical shifts of the methyl groups at positions 3 and 5 are mainly affected by the ring current effect of the substituents. This conclusion was strongly supported by the proton chemical shifts calculated using additivity rules.
Kamounah, F. S., Al-Sheibani, I. S., Shibaldain, N. L., & Salman , S. R. (1985). Proton magnetic resonance studies of substituted 3,5-dimethylbenzenes: influence of substituents on the methyl proton chemical shifts. Magnetic Resonance in Chemistry, 23(7), 251-253. . https://doi.org/10.1002/mrc.1260230707