Benzoate → Benzoic Acid

A solution of the methyl 4-[[4-(2,2,3,3,4,4,4-heptafluorobut-1-oxy)anilino]-1-piperidinyl]methyl]benzoate (0.59 g, 1.13 mmol) in a 3 to 1 mixture of THF and water (40 mL) was added LiOH.H2O (8 eq, 385 mg). The reaction mixture was heated at reflux with stirring for 10 h. The reaction was allowed to cool, concentrated, diluted with water (3 mL), and acidified to a pH of 6 with an aqueous solution of 2N HCl. The solid was collected by filtration, dried, and recrystallized from water (5 mL) to give 0.32 g of 4-[[4-(2,2,3,3,4,4,4-heptafluorobut-1-oxy)phenylamino]-1-piperidinyl]methyl]benzoic acid; 1H NMR (400 MHz, DMSO-d6) δ 7.86 (d, 2H), 7.38 (d, 2H), 6.668 (d, 2H), 6.50 (d, 2H), 4.60 (t, 2H), 3.50 (s, 2H), 3.30 (br., 1H), 3.10 (m, 1H), 2.75 (m, 2H), 2.05 (m, 2H), 1.85 (m, 2H), 1.30 (m, 2H) ppm.