Ethanol → Ethyl 5-chloro-3-fluoropicolinate

Beteiligte Stoffe

Reaktionsbedingungen

Reaktionsschritte

An autoclave is charged with 31.4 g of 2,5-dichloro-3-fluoropyridine, 400 ml of dry ethanol, 27.8 ml of triethylamine and 3.5 g of palladium bis(triphenylphosphine) dichloride (PdCl2(PPh3)2) and then a pressure of 180 bars is applied with carbon monoxide. The mixture is maintained at 90° C. for 4 days. After cooling and releasing the pressure, a further 3.5 g of PdCl2(PPh3)2 are added, a pressure of 130 bars is applied with carbon monoxide, and the mixture is maintained at 90° C. for 3 days, after which it is cooled to 25° C., the pressure is released and the mixture is discharged. After concentration in vacuo, absorption from ethyl acetate onto silica gel is carried out. The silica gel is applied to a flash chromatography column (silica gel) and then eluted with n-hexanelethyl acetate 3/1. 24.3 g of the desired target compound having a melting point of 48-50° C. are obtained.

Herkunft & Nachweise