Metal-Free Eliminative C-H Arylthiolation of 2<i>H</i>-Imidazole N-Oxides with Thiophenols

Abstract

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 (SNH) in non-aromatic azaheterocyclic substrates via the “addition-elimination” (SNH 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.

Keywords

• azaheterocycles
• imidazoles
• thiophenols
• C-H functionalization
• nucleophilic substitution of hydrogen