Assembly of New Heterocycles through an Effective Use of Bisaldehydes by Using a Sequential GBB/Ugi Reaction.

A facile route for the assembly of new bis-heterocyclic imidazo[2,1-b][1,3]thiazinyl/benzothiazoyl-phenyl)benzamide scaffolds through a two-step Groebke-Blackburn-Bienaymé (GBB)/Ugi reaction sequence is reported, which establishes multiple points of diversity in the final products. The highlights of this procedure are the survival of the aldehyde group following the GBB reaction without the need for additional protection/deprotection steps. Moreover, the reaction is operationally simple, with the absence of any catalyst, and exhibits excellent functional-group tolerance under minutes of microwave irradiation.