The synthesis of 4-(4-nitrophenyl)morpholin-3-one was carried out by two steps of synthesis as shown in figure below.
[1]Step 1: Finely ground potassium permanganate (0.474 g, 3.00 mmol) was added to a stirred solution of the 4-phenylmorpholine (0.326 g, 2.00 mmol) and benzyltrimethylammoniun chloride (0.683 g, 3.00 mmol) in dichloromethane (10 mL), and the purple solution was stirred at reflux for 3 h. The mixture was cooled in ice and a solution of sodium bisulfite (2 g) in water (10 mL) was added and separated; the aqueous phase was extracted with chloroform (3 × 10 mL). The combined organic extract was washed with water (20 mL) and dried with Na2SO4. The solvent removal gave a residual yellow solid (0.205 g, 56% yield) which was recrystallized from hexane to give 4-phenylmorpholin-3-one (0.135 g, 35% yield).
Step 2: To a solution of 4-phenylmorpholin-3-one (0.995 g, 5.62 mol) at 98%, H2SO4 (2.33 mL) cooled to −10 °C 65% HNO3 was carefully added dropwise (0.4 mL) over 45 min. The reddish solution obtained was stirred at this temperature for 1 h and H2O (5 mL) was added. The mixture was neutralized with 35% NH4OH until pH 7. The resulting precipitate was filtered, washed with cold water and dried, resulting in 4-(4-Nitrophenyl)morpholin-3-one (1.01 g, 83% yield) as a brown solid.
