A microwave-assisted synthetic approach to analyzing disubstituted pyrrolo[2,3-d]pyrimidine diversity via ligand-free Cu-catalyzed N-arylation

Facile introduction of diverse substituents to 2- or 4-chloro-7H-pyrrolo[2,3-d]pyrimidines was examined with microwave-assisted nucleophilic substitution and Cu-catalyzed N-arylation. Microwave-assisted Cu-catalyzed N-arylation of pyrrolo[2,3-d]pyrimidines with various nucleophiles proceeded very well with diverse heteroaryl halides. Sequential microwave-assisted substitution provided good to excellent yields of 2,7- or 4,7-disubstituted pyrrolo[2,3-d]pyrimidines, with short reaction times and energy savings compared with conventional thermal heating. The diverse pyrrolo[2,3-d]pyrimidine derivatives are useful for screening drug candidates for various diseases.