We report here a practical and metal-free synthesis of novel enantiopure amides containing the drug-like 5-nitroimidazole scaffold. The first step was a metal-free diastereoselective addition of 4-(4-(chloromethyl)phenyl)-1,2-dimethyl-5-nitro-1H-imidazole to enantiomerically pure N-tert-butanesulfinimine. Then, the N-tert-butanesulfinyl-protected amine was easily deprotected under acidic conditions. Finally, the primary amine was coupled with different acid chlorides or acids to give the corresponding amides. The mild reaction conditions and high tolerance for various substitutions make this approach attractive for constructing pharmacologically interesting 5-nitroimidazoles.
Keywords: 5-nitroimidazoles; amides; metal-free.