Piperazine → 5-Methyl-2-(piperazin-1-yl)-1,3-benzoxazole

Reaction equation

[CH3:1][C:2]1[CH:3]=[CH:4][C:5]2[O:9][C:8](S)=[N:7][C:6]=2[CH:11]=1.P(Cl)(Cl)(Cl)(Cl)Cl.[NH:18]1[CH2:23][CH2:22][NH:21][CH2:20][CH2:19]1>C1(C)C=CC=CC=1>[CH3:1][C:2]1[CH:3]=[CH:4][C:5]2[O:9][C:8]([N:18]3[CH2:23][CH2:22][NH:21][CH2:20][CH2:19]3)=[N:7][C:6]=2[CH:11]=1

Participants

Procedure

A 100 mg portion of 5-methyl-2-mercaptobenzoxazole was suspended in 20 ml of anhydrous toluene, and the suspension was mixed with 150 mg of phosphorus pentachloride and heated under reflux for 1 hour. The reaction solution was cooled in an ice bath and, with stirring, 500 mg of piperazine was added thereto. After 30 minutes of stirring, the ice bath was removed to carry out 1 hour of stirring at room temperature, the reaction solution was mixed with saturated sodium bicarbonate aqueous solution, and then the water layer was washed with ethyl acetate and concentrated under a reduced pressure. Thereafter, the thus obtained mixture was purified by an LH-20 gel column chromatography (chloroform:methanol=1:1) to obtain the title compound (40 mg) in white color.