Hydrochloric Acid → 2-Trifluoroacetyl-1-tetralone

Participants

Reaction Steps

A 250 mL one necked round bottomed flask equipped with a reflux condenser, nitrogen inlet and provisions for magnetic stirring was charged with ethyl trifluoroacetate (28.4 g, 0.2 mol) and 75 mL of ether. To this solution was added 48 mL of 25% sodium methoxide in methanol (0.21 mol). A solution of 1-tetralone (29.2 g, 0.2 mol) in 50 mL of ether was added over about 5 minutes. The reaction mixture was stirred at room temperature for 14 hours and was diluted wih 100 mL 3N HCl. The phases were separated and the organic layer was washed with 3N HCl, and with brine, dried over anhydrous MgSO4, filtered and concentrated in vacuo. The residue was taken up in 70 mL of boiling ethanol/water and cooled to room temperature, whereupon crystals of 2-trifluoroacetyl-1-tetralone formed which were isolated by filtration and air dried to give pure compound (32 g, 81%): mp 48-49° C.; 1H NMR CDCl3 δ 2.8 (m, 2H), 2.9 (m, 2H), 7.2 (d, J=3.0 Hz, 1H), 7.36 (m, 1H), 7.50 (m, 1H), 7.98 (m, 1H); 19F NMR CDCl3 δ −72.0. EI GC−MS M+=242.

Provenance & Evidence