Nitroaromatic Ring Research Articles

The role of supporting electrolyte during the electrocatalytic hydrogenation of aromatic compounds

The electrocatalytic hydrogenation of benzene, aniline, and nitrobenzene was investigated at a Raney nickel powder cathode. The single phase electrolyte consisted of t-butanol, water, and a hydrotropic salt, either sodium or tetraethylammoniump-toluenesulphonate (TEATS). The hydrogenation of benzene was achieved only in the latter case; the only product detected was cyclohexane. The highest current efficiency (73%) was obtained at 50° C, 1.0m benzene, 2.5m TEATS, and at an apparent current density of 4.0 mA cm−2. Aniline was electrocatalytically hydrogenated to cyclohexylamine only in the presence of a quaternary ammonium ion supporting electrolyte (containing either Br− orp-toluenesulphonate anions), with product current efficiencies of ∼40%. When nitrobenzene was hydrogenated with a sodiump-toluenesulphonate supporting electrolyte, only nitro group reduction was observed. When the supporting electrolyte was TEATS, both nitro group reduction and aromatic ring hydrogenation occurred.

Reactions of Organic Anions, 163 Reactions of Nitrobenzophenones with Carbanions Containing Leaving Groups. Vicarious Nucleophilic Substitution of Hydrogen versus Darzens or Wittig‐Horner Reactions

AbstractCarbanions containing leaving groups at the carbanion center react with nitrobenzophenones by two general pathways: addition to the carbonyl group which results in the Darzens or Wittig‐Horner reaction and/or addition to the nitroaromatic ring resulting in the vicarious nuclephilic substitution of hydrogen. The former pathway dominates for p‐nitrobenzophenone, and the vicarious nuclephilic substitution is the major process for o‐nitro‐benzophenone; the extent of these two reactions for m‐nitrobenzophenone depends on the type of carbanion and the reaction conditions.