Synthesis of 6-triazolylmethyl-pyrrolo[3,4-b]pyridin-5-ones by an efficient MW-assisted (Ugi-3CR / aza Diels-Alder) / Click process

In this work, we describe the synthesis of novel triazolylmethyl-pyrrolo[3,4-b]pyridin-5-ones by a sequence: Ugi-3CR / aza Diels-Alder / Click. There are several reports about pyrrolo[3,4-b]pyridin-5-ones related to various type of biological activity.We reported two methodologies for synthesizing series of novel pyrrolo[3,4-b]pyridine-5-ones using Ugi reactions combined with further condensation processes. In the first, a series of tetrahydroisoquinolin-pyrrolopyridinones was prepared by a sequence: Ugi-3CR / aza Diels-Alder / Pummerer. In the second, aza-analogs of the natural alkaloid (±)-nuevamine were prepared by a sequence: Ugi-3CR / aza Diels-Alder / Pictet-Spengler. By using Ugi-3CR/ Aza Diels-Alder cycloaddition for the synthesis of propargyl-pyrrolopyridine intermediates with the previously-well established conditions combining propargyl amine, aldehydes, α-isocyanoamides and maleic anhydride in toluene with Sc(OTf)₃ in MW followed by CuAAC sequence for the synthesis of triazolyl products.