Synthesis of 4- and 5-benzothiazol-2-yldithio-2,6-dimethylocta-2,6-diene and other models for pendent groups in the sulphur vulcanisation of natural rubber

Abstract

Reaction of 2,6- and 3,7-dimethylocta-2,6-dien-4-ol (14) and (15) with thioacetic acid and di-isopropyl azodicarboxylate–triphenylphosphine gave, inter alia, the thioacetates (16b) and (18b). Reduction of the thioacetates afforded the thiols (16c) and (18c), which were converted into the title disulphides (21) and (22) by treatment with N-(benzothiazol-2-ylthio)phthalimide. Monosulphidic and other disulphidic model pendent groups were prepared by nucleophilic displacement reactions of the benzothiazole-2-thiolate anion with the appropriate chloro compound or Bunte salt, respectively.