Synthesis of fused quinoxalines

Synthesis of Heteroannulated Indolopyrazines through Domino N–H Palladium-Catalyzed/Metal-Free Oxidative C–H Bond Activation

“…Further treatment of amination products 6b–d by acids, followed by oxidation with air oxygen, also leads to similar cyclization products 7b–d . Following the literature, trifluoroacetic acid was used for the cyclization of thiophenyl-substituted quinoxaline 6b , while a mixture of hydrochloric acid in ethanol led to the transformation of amino derivatives 6a , c into indolopyrazines 7c , b in high yields (Scheme ).…”

Intramolecular Nucleophilic Substitution of Hydrogen in (Quinoxalinyl‐2)aminovinyl Derivatives as a New Approach to Pyrrolo‐ and Indolo[2,3‐b]quinoxalines

“…1). [7] In this paper, we wish to report a facile synthesis of pyrrolo[2,3-b]and indolo[2,3-b]-quinoxalines through intramolecular S N H -reactions of (quinoxalinyl-2)aminovinyl derivatives obtained from 2-aminoquinoxalines 1a,b (Schs. 2).…”

Nucleophilic attack on the unsubstituted carbon atom of azines and nitroarenes as an efficient methodology for constructing heterocyclic systems

“…These reactions led to the intramolecular nucleophilic substitution of hydrogen at the a position with respect to the quaternary nitrogen atom. 53 Yet another example of the intramolecular oxidative nucleophilic substitution of hydrogen is the reaction of 2-aminoquinoxaline 72 with acetylacetone or cyclohexanone. 54 Schiff's bases 73 generated in the course of the reactions underwent spontaneous cyclisation to pyrrolo [2,3-b]quinoxaline derivatives 74.…”