An Efficient Synthesis of the 2H-pyrano[3,2-c]quinoline-2,5(6H)-dione System via Tandem Reaction of 4-hydroxyquinolinones to Baylis-Hillman Adduct Acetates

4-hydroxyquinolinones 7 were applied as 1,3-dinucleophiles in the reaction with Baylis-Hillman adduct acetates 6 to synthesize, in high yields of 75-92%, novel 2H-pyrano[3,2-c]quinoline-2,5(6H)-diones which are present in a number of biologically active compounds. The reaction was carried out under different conditions to achieve the optimum ones. The results indicated that acetonitrile as solvent and K2CO3 as base, under reflux conditions, were the optimum conditions. The reaction times are short and the experimental procedure is straightforward.