Paal-Knorr reaction of aniline and 2,5-diketonePaal-Knorr reaction of aniline and 2,5-diketone
SyntheticPage 553
Published Apr 06, 2012
To a 250 mL one-necked round bottom flask equipped with stir bar was added aniline (2.79 g, 0.030 mol), 2,5-Hexanedione (3.65 g, 0.032 mol), and toluene (75 mL, 0.4 M in aniline). Upon mixing for 5 minutes, p-TsOH (0.114 g, 0.0006 mol) was added all at once. The flask was then equipped with a Dean-Stark trap and reflux condenser. The solution was heated to reflux (≈120 oC). for 1 houra. After this time the flask was cooled to room temperature and the solution was transferred to a 500 mL separatory funnel. The organic layer was washed with a saturated sodium bicarbonate solution (2 X 100 mL), deionized water (2 X 100 mL), and finally with brine (2 X 100 mL). The organic layer was dried with Na2SO4 and the solvent was removed by rotary evaporation to afford a greenish solidb,c (3.69 g, 72%).