Carbamoylation of imidazo[1,2-a]pyridine derivatives using oxamic acids under mild conditions

Amide-containing heteroaromatics have attracted considerable attention due to the widespread occurrence of amide functionalities in proteins, pharmaceuticals, and polymers. Among recent methodologies, carbamoylation stands out because it proceeds under milder conditions, offers improved atom economy, and minimizes functional group incompatibilities.¹ In this work, oxamic acid derivatives are being investigated as carbamoyl radical precursors under oxidative conditions for the C–H functionalization of imidazo[1,2-a]pyridines, relevant heterocycles present in several pharmaceutical compounds.²˒³ To date, different reaction conditions have been evaluated, including variations in the oxidant, reaction time, and energy source. The best result obtained so far employed ammonium persulfate as the oxidant and a reaction time of 20 h under blue LED irradiation, affording a monocarbamoylated product in 20% yield. NMR analyses confirm the formation of the carbamoylated product, although the position of the carbamoyl group remains uncertain. Further studies are currently underway to optimize the reaction conditions and complete the structural assignment.