反应详情

A mixture of 2-iodothiophene (Aldrich Co., 1.0 g), 1-(tert-butoxycarbonyl)piperazine (Aldrich Co. (hereafter the same), 1.06 g), copper(I) iodide (45 mg), ethylene glycol (530 μl), potassium phosphate (2.02 g) and 2-propanol (5 ml) was heated under reflux for 20 hr. Ethyl acetate was added, and the mixture was filtered through a Celite (trademark) filter. The filtrate was washed 3 times with 28% aqueous ammonia, and then washed with saturated brine. The solvent was evaporated under reduced pressure to give a brown solid. The solid was purified by silica gel column chromatography (elution solvent: ethyl acetate-hexane (7:3)) to give 4-(2-thienyl)piperazine-1-carboxylic acid tert-butyl ester (984 mg, yield 77%).

1. temperatureunder reflux for 20 hr
2. filtrationthe mixture was filtered through a Celite (trademark)
3. filtrationfilter
4. washThe filtrate was washed 3 times with 28% aqueous ammonia
5. washwashed with saturated brine
6. customThe solvent was evaporated under reduced pressure
7. customto give a brown solid
8. customThe solid was purified by silica gel column chromatography (elution solvent: ethyl acetate-hexane (7:3))