Ethyl Acetate → (6-Chloropyridazin-3-yl)methanol

Beteiligte Stoffe

Reaktionsbedingungen

Reaktionsschritte

4.3 g (21.4 mmol) of 6-chloropyridazine-3-carboxylic acid are dissolved in 60 ml of dry toluene and heated to 60° C. At this temperature, 3.8 g (32.2 mmol) of thionyl chloride are added, and the mixture is stirred at this temperature for 3 h. The mixture is then heated at reflux for 4 h. After cooling to RT, the solvent is removed on a rotary evaporator. 20 ml of toluene are added, and the mixture is again evaporated to dryness. The residue is dissolved in 40 ml of methyl tert-butyl ether and cooled to 5° C. At this temperature, a solution of 1.7 g (47.2 mmol) of sodium borohydride in 37 ml of water is added dropwise. The mixture is stirred at RT for 20 h. 50 ml of ethyl acetate are then added, and the aqueous phase is extracted three times with in each case 10 ml of ethyl acetate. The combined organic phases are washed in each case twice with in each case 10 ml of sat. sodium bicarbonate solution and water. The solvent is removed on a rotary evaporator and the residue is purified chromatographically on silica gel 60 (mobile phase: gradient dichloromethane/ethanol 100:1→20:1).

Herkunft & Nachweise