Synthesis of novel imidazopyridine-oxadiazole molecular hybrids by a regioselective sulfenylation of imidazo[1,2-a]pyridines with 1,3,4-oxadiazole-2-thiols using I2-FeCl3 catalytic system and O2/air as co-oxidant

Imidazo[1,2-a]pyridine and 1,3,4-oxadiazole are privileged scaffolds in medicinal chemistry owing to their diverse biological as well as pharmacological properties. They also have wide applications in material chemistry due to their interesting photophysical properties. Combining these two scaffolds through a thioether linkage leads to novel imidazopyridine-oxadiazole hybrids. This has been achieved by a regioselective C-3 sulfenylation of imidazo[1,2-a]pyridines with 1,3,4-oxadiazole-2-thiols using I2-FeCl3 as an efficient catalytic system and aerial oxygen as co-oxidant. This protocol provides a general, mild, efficient and atom-economic method for C-3 sulfenylation of imidazo[1,2-a]pyridines with 1,3,4-oxadiazole-2-thiols, a class of heterocyclic thiols not being used in such reactions.