2-BROMO-1,3-DI(METHOXY)IMIDAZOLIUM TRIBROMIDE AS STARTING SALT FOR 2-ARYL- AND 2-HETEROARYLMERCAPTO DERIVATIVES

摘要

A one-pot alkylation/bromination sequence of 1-hydroxyimidazole 3-oxide led to the simple isolation of new 2-bromo-1,3-di(methoxy)imidazolium tribromide 1 by spontaneous precipitation from the aqueous reaction mixture. The related bromide 2, quantitatively and cleanly derived from the tribromide 1 via sacrificial bromination of cyclohexene, as well as the hexafluorophosphate 3, easily accessible through anion metathesis, represent valuable congeners for a rich follow-up chemistry. The reactivity of the 2-bromo substituent towards nucleophilic substitution by different S-nucleophiles was chosen as a starting point. Thus, a series of 2-arylmercapto- and 2-hetarylmercaptoimidazolium salts, which are otherwise only elaborately to access, could be isolated with minimal effort. In addition to routine spectroscopic characterization, eleven selected compounds have been determined using single-crystal X-ray diffraction.