Iodine mediated in situ generation of R-Se-I: application towards the construction of pyrano[4,3-b]quinoline heterocycles and fluorescence properties.

In this paper, we report the iodine mediated in situ generation of R-Se-I and further its application towards the construction of pyrano[4,3-b]quinolin-1-one derivatives. The structural elaboration of 1-chloro-8-methyl-3-phenylbenzo[b][1,6]naphthyridine 6 was successfully achieved by Sonogashira, Suzuki coupling and dehalogenation reactions. Finally, the synthesized compounds 4a, 5a, 5b, 6, and 7a-7c were studied for photophysical properties including UV-absorption, fluorescence, and quantum yield studies. The synthesized pyranoquinoline derivatives showed λmax, Fmax and Φf values in the range of 391-447 nm, 436-486 nm and 0.004-0.301, respectively in chloroform solvent.