Nitration of toluene, t-butylbenzene, and 4-substituted 1-phenylbicyclo[2.2.2]octanes with nitric acid–acetic anhydride. Evidence for a π-inductive effect

Abstract

The nitration of toluene, t-butylbenzene, and 1-phenyl -4-X-bicyclo [2.2.2] octanes (X = H, Me, Et, Prⁱ, OMe, CO₂Me, Br, Cl, F, CN, or NO₂) in acetic anhydride with fuming nitric acid-acetic anhydride at 25.0 °C has been studied, and the percentages of the mononitro-products formed and values of the partial rate factors (f) have been determined. The log f values for each position are successfully correlated with σ₁ values. The substituent effects on positions in the benzene ring decrease from the ortho- to the para- to the meta-position; this order is compatible with the operation of a π-inductive effect.