Styliana I Mirallai et al.
The Journal of organic chemistry, 78(17), 8655-8668 (2013-07-31)
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