4-Chlorophenol → 165383-52-8

Participants

Reaction Conditions

Reaction Steps

The reactor was loaded with 4-chlorophenol (58.5 g), (S)1-(1,2,4-triazolo[1,5-a]pyrimidin-7-yl)ethanol (50 g), triphenylphosphine (85 g) and toluene (900 ml). The suspension was cooled to 5-10° C. and diisopropyl azodicarboxylate (65 ml) was added over 2 hours. After complete addition of diisopropyl azodicarboxylate the solution was stirred while warming to ambient temperature. The reaction mixture was re-cooled to 0° C. and filtered. The filtrate, magnesium chloride (anhydrous; 31.1 g) and celite (25.5 g) were combined in the reactor. Toluene (500 ml) was distilled off and the remaining mixture was cooled to 0° C. The suspension formed was removed by filtration. Further magnesium chloride (2.6 g) and celite (2.5 g) were added to the filtrate. Toluene (200 ml) was removed by distillation. The residue was cooled to 0° C. and filtered. The filtercake was washed with toluene. The reactor was loaded with the filtrate, and toluene was removed by azeotropic distillation with propan-2-ol. The product crystallised from propan-2-ol at 40° C. while cooling to 20° C. The product was collected by filtration and washed with propan-2-ol. After drying, the product (R)-7-[1-(4-chlorophenoxy)ethyl]-1,2,4-triazolo[1,5-a]pyrimidine (61.1 g) was obtained (yield: 73.6%; HPLC analysis: 99.1%; chiral HPLC: ee=100%). No triphenylphosphine oxide was detectable by HPLC analysis.

Provenance & Evidence