Unusual Friedlander reactions: a route to novel quinoxaline-based heterocycles.
Acid catalyzed Friedlander reactions of a number of 2,3-dihydro-1H-cyclopenta[b]quinoxaline-1-ones with 2-aminobenzaldehyde yield, unexpectedly, 8H-indolo[3,2-a]phenazine and quinolino[2,3-c]cyclopentadienone[2,3-b]quinoxalines, the structures of derivatives of which were confirmed by X-ray crystallography. Easy routes to novel quinoxaline-based indoles, quinolones, and quinoxaline-1,4-dioxides are reported, and proposed mechanisms for the unexpected products are discussed.
Department of Chemistry, American University of Beirut , Beirut, Lebanon, and Department of Chemistry, University of California , One Shields Avenue, Davis, California 95616, United States.
Tharallah A
TA
Shoker
Khaled I
KI
Ghattass
James C
JC
Fettinger
Mark J
MJ
Kurth
Makhluf J
MJ
Haddadin
D018360:Crystallography, X-Ray; D003517:Cyclopentanes / Q000737:chemistry*; D015394:Molecular Structure; D011810:Quinoxalines / Q000138:chemical synthesis* / Q000737:chemistry*
D003517:Cyclopentanes; D011810:Quinoxalines; C003282:quindoxin