AlCl₃-Promoted Intramolecular Indolinone-Quinolone Rearrangement of Spiro[indoline-3,2′-quinoxaline]-2,3′-diones: Easy Access to Quinolino[3,4-b]quinoxalin-6-ones

Abstract

A facile and direct intramolecular indolinonequinolone rearrangement was developed for the synthesis of quinolino [3,4-b]quinoxalin-6-ones from spiro[indoline-3,2′-quinoxaline]-2,3′-diones, which are readily available with use of isatines, malononitrile, and 1,2-phenylenediamines under quite mild conditions. This efficient approach provides excellent yields and could potentially be used for the construction of a diverse library of quinolino [3,4-b]quinoxalin-6-ones for high-throughput screening in medicinal chemistry. The reaction mechanism is explored by extensive DFT calculations.

γ-Hydroxy-γ-butyrolactams as 1,2-bis-electrophiles in a Brønsted/Lewis acid-free synthesis of condensed nitrogen heterocycles

“…These factors motivate the pursuit of alternative reagents exhibiting enhanced chemoselectivity, stability, and, consequently, the ability to remain unaltered within the substrate until the required moment without changes. α-Halogen ketones, 14 geminal alcohols 15 and epoxides 16,17 can be used as hidden analogues (Scheme 1b–d, respectively). All the above reagents remain highly reactive and necessitate the use of various catalysts and reagents, including oxidizing agents, which can interact with other functional groups within the molecule.…”