Metal-Free Eliminative C-H Arylthiolation of 2H-Imidazole N-Oxides with Thiophenols

A synthetic strategy based on reactions of cyclic imine oxides, namely 2H-imidazole 1-oxides, with thiophenols mediated by acetyl chloride was successfully applied as a convenient tool to obtain a series of novel azaheterocyclic molecules, including water-soluble hydrochloride forms. Optimized reaction conditions found herein for the nucleophilic substitution of hydrogen (S-N(H)) in non-aromatic azaheterocyclic substrates via the "addition-elimination" (S-N(H) AE) scheme enabled 15 arylthiolated 2H-imidazoles to be prepared in yields of up to 90%. The developed methodology discloses an original synthetic way to obtain numerous azaheterocyclic molecules, which are of interest in the field of medicinal chemistry and materials science.