Synthesis of fluorinated furo- and pyrrolo[3,4-b]quinoxaline 4,9-dioxides

Quinoxaline 1,4-Dioxide: A Versatile Scaffold Endowed With Manifold Activities

“…to the quinoxaline 1,4-dioxides, is well-documented [88,132,[147][148][149][150][172][173][174][175][176]. Some examples are showed in Fig.…”

“…BFO's also react with β-diketone derivatives to form 2-acyl-quinoxaline 1,4-dioxides (6) [130,141,[144][145][146] and with β-ketoesters to give 2-carboxyalkyl derivatives (7) of Fig. (18) [131,[147][148][149][150]. Furthermore, 2-carboxamide derivatives (8) are obtained by condensation of BFO's with β-ketoamides of Fig.…”

Fluorinated benzazoles and benzazines

“…Reacting with CH-active carbonyl compounds, enamines or nitriles 5,6-difluorobenzofuroxane 8 (R = F) was transformed into the corresponding 6,7-difluoroquinoxalin-1,4-dioxides 9 [19][20][21]. Nucleophilic displacement of a fluorine atom at C-6 in furoxane 8 allows one to modify the benzene ring, while the furoxane ring remains unchanged in this reaction (compounds 10).…”

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

“…[5,6] In addition, we have recently described a new methodology for the synthesis of fused quinoxalines, which is based on nucleophilic displacement of hydrogen (S N H ), as illustrated by the intramolecular reaction in which quinoxalinyl hydrazones are converted into pyrazolo [3,4-b]quinoxalines (Sch. The starting 6,7-difluoro-2-aminoquinoxaline 1a was obtained from 2-amino-6,7-difluoro-3-cyanoquinoxaline-1,4-dioxide, [8] while 2-aminoquinoxaline 1b was prepared according to the known procedure from ortho-phenylenediamine and alloxane. [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.…”