反应详情

Trifluoromethanesulfonic acid 3-methyl-2-nitrophenyl ester (26.7 g, 93.6 mmol), 1-tert-butoxycarbonyl piperazine (17 g, 91.3 mmol) and triethylamine (14 mL, 100 mmol) in 250 mL of acetonitrile was heated under reflux for 25 h. The mixture was concentrated in vacuo, diluted with water and extracted with ether. The ether was washed with aqueous ammonium hydroxide and brine, dried, and evaporated. Purification by silica gel chromatography (10% ethyl acetate-hexane) afforded 11 g of 4-(3-methyl-2-nitrophenyl)-piperazine-1-carboxylic acid tert-butyl ester as a golden solid, m.p. 101-102° C.

1. temperatureunder reflux for 25 h
2. concentrationThe mixture was concentrated in vacuo
3. additiondiluted with water
4. extractionextracted with ether
5. washThe ether was washed with aqueous ammonium hydroxide and brine
6. customdried
7. customevaporated
8. customPurification by silica gel chromatography (10% ethyl acetate-hexane)