Construction of functionalized tricyclic dihydropyrazino-quinazolinedione chemotypes via an Ugi/N-acyliminium ion cyclization cascade

Herein, we report the production of a diversified tricyclic scaffold in 3 synthetic operations involving an Ugi multicomponent reaction followed by an N-acyliminium ion cyclization cascade. Further functionalization of the biologically appealing tricyclic core 24 was achieved via sequential N-alkylation and N-acylation and/or sulfonation.