Ethanone, 1-(2-benzoxazolyl)- (9CI)

61533-67-3

122433-29-8

1. 5.45 g (0.05 mol) of 2-aminophenol and 22.5 g (0.25 mol) of lactic acid were added to a 50 mL round-bottomed flask and heated to reflux for 6 h. After the reaction was completed, it was cooled to room temperature. The pH was adjusted with concentrated ammonia until the violet litmus paper turned red, the solid product was collected by filtration and recrystallized with petroleum ether in 78% yield. 2. In a 50 mL three-necked flask, 3.26 g (0.02 mol) of 1-(1,3-benzoxazol-2-yl)ethan-1-ol and 20 mL of glacial acetic acid were added. After heating to 90°C, CrO3 aqueous solution was added slowly dropwise. After the dropwise addition, the reaction was stirred at 105°C for 20 minutes. The reaction mixture was poured into 200 mL of water, stirred briefly and filtered. The filtrate was extracted three times with chloroform, the chloroform layers were combined and dried with anhydrous magnesium sulfate. The solvent was removed by evaporation to give a yellow solid which was recrystallized from toluene in 81% yield. 3. 20 mL of 95% ethanol and 3.22 g (0.02 mol) of 1-(benzothiazol-2-yl)ethan-1-ol were added to a 50 mL round-bottomed flask and stirred for about 10 minutes until the solid was completely dissolved. Subsequently, 8 mL of 10% aqueous sodium hydroxide solution was added and 0.02 mol 2-pyridinecarboxaldehyde was added under stirring. The progress of the reaction was monitored by TLC during the reaction and the solid product was obtained by filtration in 73% yield after completion of the reaction.