STUDIES ON THE DEUTERATION OF AROMATIC ORGANOSULFUR COMPOUNDS USING AQUEOUS TRANSITION METAL SPECIES

Abstract

Reaction of benzenethiols and benzo[b]thiophene (BT) with D₂O solutions of trichlorides of Ru, Fe or Cr at elevated temperatures (200–315°C) constitutes a simple method for the preparation of per-deuterated derivatives. Substitution patterns observed for partially deuterated products imply that D-incorporation occurs by standard electrophilic processes. Reactions with benzenethiols produced diaryl sulfides as by-products although these compounds were deuterated to the same extent as the thiols. Experimental observations and the known behaviour of aqueous transition metal species indicate that D⁺ is furnished by the hydrolysis of D₂O molecules in the solvation sphere of the metal ion. Complete deuteration of the organosulfur substrates was achieved using a 100: 1 organosulfur/metal chloride mole ratio. Hydrodesulfurization of per-deuteroBT under standard conditions afforded perdeuteroethylbenzene in good yield.

Key Words:

• Aromatic organosulfur compounds
• deuteration
• aqueous transition metal salts.