Acrylic Acid → 6-fluoro-2,3-dihydro-4H-1-benzopyran-4-one

Participants

Reaction Conditions

Reaction Steps

A 400 ml stainless steel Parr reactor was charged with para-fluorophenol (28.4 grams), acrylic acid (28.8 grams), and an inhibitor phenothiazine (0.02 grams). The system was sealed, evacuated and cooled in dry ice/acetone before the anhydrous hydrogen fluoride (117 grams) was condensed into the system. The mixture was then warmed to 40° C. for one hour thirty minutes with stirring before being heated to 100° C. for four hours thirty minutes. The excess HF was them removed and the system cooled to 0° C. and opened to give 62 grams of brown oil which was washed with D.I. water to give 50 grams of material to be extracted. The 6-Fluoro-4-Chromanone was collected and recrystallized from methanol/water. The HPLC yield was 75%, isolated 52%.

Provenance & Evidence