Hydrochloric Acid → N-Ethyl-4-hydroxy-4-(3-(1-methylethoxy)phenyl)piperidine

Temperatur

-20 °C

To a stirred solution of 1-bromo-3-(1-methylethoxy)benzene (5.0 g, 23 mmol) in anhydrous tetrahydrofuran (50 ml) at −78° C. under an atmosphere of nitrogen was added n-butyllithium (1.6M in hexane, 13.7 ml, 22 mmol) dropwise. The reaction mixture was stirred for 1 h at −78° C., before N-ethyl-4-piperidone (2.95 ml, 22 mmol) was added dropwise at −78° C. over 15 minutes, and the reaction mixture was then warmed to −20° C. over 30 minutes. The solution was poured onto 2N aqueous hydrochloric acid (35 ml) and this was further acidified to pH 1 with concentrated hydrochloric acid. Hexane (50 ml) was added and the two layers were separated. The organic layer was discarded and the pH of the aqueous layer was adjusted to 14 using sodium hydroxide pellets. The basic aqueous layer was extracted with hexane:diethyl ether (1:1, 5×50 ml) and the combined extracts were dried (MgSO4) and concentrated to give the title compound as a crude oil (4.2 g, 73% crude yield) which was used without further purification.

1. additionwas added dropwise at −78° C. over 15 minutes
2. customthe two layers were separated
3. extractionThe basic aqueous layer was extracted with hexane:diethyl ether (1:1, 5×50 ml)
4. dry with materialthe combined extracts were dried (MgSO4)
5. concentrationconcentrated

ORD-Eintrag

ord-7393ba0c9b974ded88aa4c0987da4a30

Quelldatensatz

uspto-grants-2003_08

DOI

10.6084/m9.figshare.5104873.v1

Patentnummer

US06610711B2