A concise and optimized four-step approach toward 2-(aryl-)alkylsulfanyl-, 4(5)-aryl-, 5(4)-heteroaryl-substituted imidazoles using alkyl- or arylalkyl thiocyanates

A convenient cyclization method leading to trisubstituted imidazoles in up to 84% yield is reported. Diverse 1-aryl-, 2-heteroaryl-substituted ethanones are converted into the corresponding α-oximino derivatives which are reduced under regioselective conditions. The obtained α-amino carbonyl intermediates are reacted with alkyl- or arylalkyl thiocyanates to directly yield C2-S-substituted imidazoles.

Graphical abstractCyclization with substituted thiocyanates.Download full-size image