6-bromo-2-(3,4-dichlorophenyl)-4H-pyrano[2,3-b]pyridine

2-(3,4-dichlorophenyl)-3,4-dihydro-2H-pyrano[2,3-b]pyridine

2-(3,4-dichlorophenyl)-6-methylsulfonyl-3,4-dihydro-2H-pyrano[2,3-b]pyridine