N,N-Dimethylaniline → 4(1H)-Quinazolinone

Participants

Reaction Conditions

Reaction Steps

To a stirring suspension of benzoyleneurea 1 (10.0 g, 61.7 mmol) and phosphorus oxychloride (20 ml) in a 500 mL three-necked round-bottomed flask equipped with a magnetic stirrer and reflux condenser, was added N,N-dimethylaniline (7.80 ml, 61.7 mmol) in a single portion. The suspension was heated at reflux for 3 hours and slowly formed a light red solution. The solution was concentrated under reduced pressure and the residue was poured onto ice (100 g). The solution was basified to pH=9.0 using concentrated aqueous sodium bicarbonate solution. The mixture was partitioned between CH2Cl2 and H2O. The organic portion was dried (MgSO4) and evaporated to dryness under reduced pressure. The residue was dissolved in anhydrous THF (75 ml) and cooled to 0° C. Dimethylaniline (67.7 mL, 135 mmol, 2.0 M in THF) was added dropwise, with stirring, over a period of 30 minutes. The solution was then stirred at 0° C. for 1 hour. The solution was concentrated under reduced pressure and the residue was purified by silica gel chromatography using (70% hexanes, 30% ethyl acetate) to obtain 2 (7.90 g, 38.1 mmol, 62% yield) as a white solid.

Provenance & Evidence