反应详情

N-[8-(2,4-Dichlorophenyl)-2-ethylimidazo[1,2-a]pyrazin-3-yl]-N-propylamine (296 mg, 0.85 mmol) and propionaldehyde (0.19 mL, 2.6 mmol) were dissolved in tetrahydrofuran (1.1 mL), and 3M sulfuric acid (0.87 mL, 2.6 mmol) was added thereto. Sodium borohydride (70 mg) was added thereto under ice-cooling, and the mixture was stirred for 3 hours. Water was added to the reaction mixture, which was neutralized with a 2N aqueous sodium hydroxide solution and extracted with ethyl acetate. The organic layer was dried over anhydrous magnesium sulfate, and evaporated. The resulting residue was purified by silica gel column chromatography (ethyl acetate:n-hexane=1:2) to give N-[8-(2,4-dichlorophenyl)-2-ethylimidazo[1,2-a]pyrazin-3-yl]-N,N-dipropylamine (272 mg) as pale yellow crystals. The resulting free compound was converted into hydrochloride with hydrochloric acid-ether using the conventional method, to give the title compound (250 mg) as white crystals.

1. temperatureunder ice-cooling
2. extractionextracted with ethyl acetate
3. dry with materialThe organic layer was dried over anhydrous magnesium sulfate
4. customevaporated
5. customThe resulting residue was purified by silica gel column chromatography (ethyl acetate:n-hexane=1:2)