Methyl substituent effects in the ¹³C spectra of cyclohexanone O‐methyl oximes and N,N‐dimethylhydrazones

The 13 C NMR spectra of a series of 4‐ t ‐butylcyclohexane‐ O ‐methyl oximes and N , N ‐dimethylhydrazones containing α‐methyl substituents have been measured. The effects of α‐methyl substitution ( syn ‐axial, anti ‐axial and anti ‐equatorial) on the carbons α, β and γ to the substitution site are similar to those previously found in cyclohexanones. Use has been made of these substituent parameters to determine the conformational equilibria of the mobile 2‐methylcyclohexanone derivatives.