Pyridine → 5-Fluoro-1,4-benzodioxane-2-carbonitrile

Participants

Reaction Steps

13.7 ml of pyridine (169 mmol, 2 eq.) are added to a suspension of 16.7 g of amide from Stage 1 (84.5 mmol) in 180 ml of dioxane at 0° C., followed, 10 minutes later, by dropwise addition of 13.1 ml of trifluoroacetic anhydride (19.5 g; 93 mmol, 1.1 eq.). The reaction mixture is kept cold for 1 hour and is then stirred at room temperature for 16 hours. The solution is taken up in Et2O/1N HCl. The organic phase is washed with 1N NaOH, dried over MgSO4, filtered and then evaporated to dryness. 16.8 g of a pale yellow oil are obtained (quantitative yield).

Provenance & Evidence