反应详情

温度

-10 °C

A solution of (6-chloro-pyridin-3-yl)-carbamic acid tert-butyl ester (4.19 g) in diethyl ether (150 mL) was cooled to −78° C. and N,N,N′,N′-tetramethylethylendiamine (6.60 g) was added. After slow addition of n-butyl lithium solution (1.32 M in hexane, 41.6 mL) over a time period of 10 minutes, the mixture was allowed to warm up to −10° C., stirred at this temperature for 2 hours and then was re-cooled to −78° C. The mixture was poured slowly into a stirred mixture of crushed dry ice in THF and stirred for 30 minutes. The mixture was concentrated on a rotary evaporator and water was added to the residue. The aqueous layer was washed 2× with MTB-ether and acidified with 6N hydrochloric acid to pH ˜3. The formed precipitate was filtered off, washed with water, ethyl acetate and dried in vacuum to afford 2.46 g of the title compound of the formula

1. temperaturewas re-cooled to −78° C
2. stirringstirred for 30 minutes
3. concentrationThe mixture was concentrated on a rotary evaporator and water
4. additionwas added to the residue
5. washThe aqueous layer was washed 2× with MTB-ether
6. filtrationThe formed precipitate was filtered off
7. washwashed with water, ethyl acetate
8. customdried in vacuum