Regioselective Synthesis of Functionalized Pyrrolo[1,2-]pyrazine-3,6(2,4)-diones via Tandem Post-Ugi Cyclization and Gold(I)-Catalyzed Annulation.

A convenient synthesis of less explored pyrrolo[1,2-]pyrazine-3,6(2,4)-diones is described in two steps from Ugi adducts. The method involves acid-mediated cyclization of Ugi adducts to form dihydropyrazinones followed by gold(I)-catalyzed regioselective annulation. The generality of the transformation was established by reacting a variety of substituted dihydropyrazinones under the optimized reaction conditions to form densely functionalized pyrrolo[1,2-]pyrazine-3,6(2,4)-diones in good-to-excellent yields.

Discovery of 2,3-dihydro-1-pyrrolo[3,4-]quinolin-1-one derivatives as possible antileishmanial agents.

A series of uniquely functionalized 2,3,-dihydro-1-pyyrolo[3,4-]quinolin-1-one derivatives were synthesized in one to two steps by utilizing a post-Ugi modification strategy and were evaluated for antileishmanial efficacy against visceral leishmaniasis (VL). Among the library compounds, compound 5m exhibited potential antileishmanial activity (CC = 65.11 μM, SI = 7.

Synthesis of β- and γ-lactam fused dihydropyrazinones from Ugi adducts a sequential ring construction strategy.

A modular approach for the construction of β- and γ-lactam fused dihydropyrazinones from the readily available Ugi adducts has been described. The sequential construction of rings through base-mediated cycloisomerization followed by acid-mediated cyclization yielded β-lactam fused dihydropyrazinones. However, the Ugi-derived dihydropyrazinones afforded γ-lactam fused dihydropyrazinones under base-mediated cycloisomerization.