Oxidation of Benzylamines by Alkyl Sulphoxides

Primary, secondary and tertiary benzylamines were oxidized to aromatic aldehydes and ketones when their HX (X = Br, I) salts were heated, under anhydrous conditions, in excess of alkyl sulphoxide. Quaternary benzylammonium salts also react, to give lower yields of carbonyl compounds. Benzylamine is being oxidized in the presence of anhydrous HX formed in situ by the reaction of alkyl halide and hydrosiloxane, but not in the presence of aqueous HX.