Guanidine hydrochloride (GuHCl)-catalysed microwave-mediated solvent- and metal-free synthesis of pyrimido[1,2-a]benzimidazole from aryl aldehyde and aryl methyl ketone

The rapid, eco-friendly, solvent- and metal-free microwave-assisted synthesis of pyrimido[1,2- a ]benzimidazole in high yields was achieved using the green organocatalyst guanidine hydrochloride using simple and inexpensive starting materials.