Synthesis of Pyrrolo[3,4-b]pyridin-5-ones via Ugi-Zhu Reaction and In Vitro-In Silico Studies against Breast Carcinoma

An Ugi-Zhu three-component reaction (UZ-3CR) coupled in a one-pot manner to a cascade process (N-acylation/aza Diels-Alder cycloaddition/decarboxylation/dehydration) was performed to synthesize a series of pyrrolo[3,4-b]pyridin-5-ones in 20% to 92% overall yields using ytterbium triflate as a catalyst, toluene as a solvent, and microwaves as a heat source. The synthesized molecules were evaluated in vitro against breast cancer cell lines MDA-MB-231 and MCF-7, finding that compound 1f, at a concentration of 6.25 μM, exhibited a potential cytotoxic effect. Then, to understand the interactions between synthesized compounds and the main proteins related to the cancer cell lines, docking studies were performed on the serine/threonine kinase 1 (AKT1) and Orexetine type 2 receptor (Ox2R), finding moderate to strong binding energies, which matched accurately with the in vitro results. Additionally, molecular dynamics were performed between proteins related to the studied cell lines and the three best ligands.

A Suitable Alternative towards Novel Aza-Analogues of Falipamil

We describe the one-pot synthesis of twenty polyheterocyclic pyrrolo[3,4-b]pyridin-5-ones via a cascade process (Ugi-3CR/aza Diels-Alder/N-acylation/aromatization) in 20 to 95% overall yields, as well as four pharmacologically promising analogues via an improved cascade process (Ugi-3CR/aza Diels-Alder/N-acylation/aromatization/SN2): two piperazine-linked pyrrolo[3,4-b]pyridin-5-ones in 33 and 34%, and a couple of Falipamil aza-analogues in 30 and 35% overall yields. It is worth highlighting the good substrate scope found, because final products are furnished with alkyl, aryl, and heterocyclic substituents. The use of chain-ring tautomerizable isocyanides (as key reagents for the Ugi-type three component reaction) allowed for a rapid and efficient assembly of the polysubstituted oxindoles, which were used in situ toward the complex products, conferring features like robustness, sustainability, and the one-pot approach to this synthetic methodology.