has specified product has specified reactant aldehyde amidine isocyanide organic heteropolycyclic compound fused-ring-system formation Groebke-Blackburn-Bienaymé reaction 2021-12-03T09:13:40Z A three-component reaction (3CR) of a heterocyclic amidine, an aldehyde, and an isocyanide, resulting in a cyclic compound with imidazo[1,2-a] heterocycle as the core structure. GBB reaction GBB‐3CR reaction RXNO:0000670 RXNO