Triethylamine → HCID 17773153, compound

Participants

Reaction Steps

To a solution of 3-(imidazo[1,2-a]pyridin-3-yl)propionic acid (4 g) synthesized according to the method described in Japanese Patent Unexamined Publication No. 189179/1983, 1-(4-chlorophenyl)piperazine hydrochloride (4.9 g) and triethylamine (5.9 ml) in dimethylformamide was added dropwise diethyl cyanophosphate (3.8 ml) under ice-cooling with stirring, and the mixture was stirred for 3 hours. After the completion of the reaction, the reaction mixture was concentrated, extracted with chloroform, washed with water and dyed over magnesium sulfate. The solution was concentrated under reduced pressure, and lithium aluminum hydride was added to a solution of the obtained 4-(4-chlorophenyl)-1-(3-(imidazo[1,2-a]pyridin-3-yl)propionyl)piperazine in tetrahydrofuran under ice-cooling with stirring, and the mixture was stirred at room temperature for 1 hour. After the completion of the reaction, the reaction mixture was treated with a mixed solvent of water-tetrahydrofuran and filtered through celite. The filtrate was concentrated under reduced pressure the obtained residue was subjected to silica gel column chromatography to give 3-(3-(4-(4-chlorophenyl)piperazin-1-yl)propyl)imidazo[1,2-a]pyridine. This compound was dissolved in a mixture of ethanol (20 ml) and conc. hydrochloric acid (20 ml) and reduced in the presence of 10% palladium-carbon (1 g) in an autoclave at 70° C. and 50 atm. After the completion of the reaction, the reaction mixture was filtered through celite. The filtrate was concentrated under reduced pressure and the obtained residue was subjected to silica gel column chromatography to give 3-(3-(4-(4-chlorophenyl)piperazin-1-yl)propyl)-5,6,7,8-tetrahydroimidazo[1,2-a]pyridine, m.p. 95-97° C. (m.p. as oxalate).

Provenance & Evidence