Access to Bis(imidazopyridine)sulfanes by Employing Cysteine as a Greener Sulfur Source

An efficient and environmentally friendly protocol has been developed for synthesizing bis(imidazopyridine)sulfanes, employing cysteine as a sulfur source. This method demonstrates a broad substrate scope, accommodating diverse electron-donating and electron-withdrawing functional groups on the imidazopyridine core. Furthermore, the protocol is successfully extended to other heterocycles: indole, azaindole, and benzo[<i>d</i>]imidazo[2,1<i>-b</i>]thiazole. Notably, this unique mechanistic approach obviates the need for transition metal catalysts and additives, offering a significant advantage over existing synthetic methodologies.