Abstract
Eight 2-phenyl-3H-imidazo[4,5-b]quinoline-9-carbonitriles 15 are prepared in four steps from N'-arylbenzamidines 11 and tetracyanoethylene (TCNE) in ~70-90% yields. The transformation involves the initial formation of N-aryl-N'-(1,2,2-tricyanovinyl)benzamidines 12 in 87-99% yields, which in MeCN undergo a 5-exodig cyclization to give the 2-[1-aryl-5-imino-2-phenyl-1H-imidazol-4(5H)-ylidene]malononitriles 13 in 84-92% yields, while in MeOH the (Z)-2-[2-phenyl-4-(arylimino)-1H-imidazol-5(4H)-ylidene]malononitriles 14 are formed in 85-94% yields. The imidazoles 14 can also be prepared directly from imidazoles 13 via a Dimroth rearrangement in either neat MeOH or in DCM with DBU. Subsequent thermolysis of imidazoles 14 in diphenyl ether affords 2-phenyl-3H-imidazo[4,5-b]quinoline-9-carbonitriles 15 in near quantitative yields. Mechanistic rationale is provided for all transformations.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
