Displacement of the acyl group in benzothiazoles by nucleophilic alkyl radicals. Homolytic aromatic ipso-substitution

Abstract

1-Adamantyl and other alkyl radicals, produced by the Ag^I catalysed decarboxylation of carboxylic acids by ammonium peroxydisulphate, react with 2-acylbenzothiazoles effecting the displacement of the acyl group to afford 2-alkylbenzothiazoles in good yield. The.reaction with 1-adamantyl radicals is facilitated by the presence of electronwithdrawing substituents in the 5- and 6-positions of the benzothiazole nucleus. The displacement process is regarded as an aromatic S_R reaction occurring at the ipso-position.