From targeted aza-Michael addition to linked azaheterocyclic scaffolds

A straightforward method for the synthesis of spaced, phenyl-linked bis(thiohydantoin) derivatives and (thio)hydantoins spiro-fused to pyrroline ring has been developed. All the synthetic strategies here presented rely on initial aza-Michael addition followed by acylation/regioselective ring-closure step involving DD, primary amine and iso(thio)cyanate in a 3-CR providing 1,3,5-trisubstituted (thio)hydantoins. The choice of opportune acyclic reagents in the sequential 3-CR followed by 1,4-nucleophilic addition/intramolecular ring closing and 1,3-dipolar cycloaddition permits a number of C–N and C–C formation that realizes different kind of linkage between several pharmacophores.