Synthesis of novel pyrano[3,2-f]quinoline, phenanthroline derivatives and studies of their interactions with proteins: an application in mammalian cell imaging.

A series of tri-cyclic pyrano[3,2-f]quinoline and phenanthroline derivatives have been synthesized by a HCl-mediated 6-'endo-trig' Michael type ring closure reaction of 6-amino-5-(3-hydroxy-3-methylbut-1-ynyl)-2H-chromen-2-one in excellent yields. The process is very simple, facile and inexpensive and can provide a diverse range of substituted quinoline derivatives from simple and easily available starting materials. Moreover, the synthesized derivatives exhibit staining property to the cultured HeLa cells after fixing and can be used as fluorophores which can bind with protein molecule.