Hydrochloric Acid → 4-(1-(4-fluorophenyl)-1H-indazol-6-yl)butanoic acid

Participants

Reaction Conditions

Reaction Steps

A mixture of ethyl 4-(1-(4-fluorophenyl)-1H-indazol-6-yl)butanoate (2, R1=4-Fluorophenyl) (17.95 g, 55.0 mmol), LiOH (3.95 g, 165 mmol), 1,4-dioxane (150 mL) and water (30 mL) was warmed in an oil bath heated to about 80° C. for about 16 h. The mixture was cooled to rt then concentrated under reduced pressure to give a solid. The material was dissolved in water (200 mL) then the mixture was acidified to about pH 1 with hydrochloric acid (6 N) (30 mL, 180 mmol). The mixture was extracted twice with EtOAc (150 mL, then 50 mL) then the combined organic solutions were dried over MgSO4, filtered and the filtrate concentrated under reduced pressure to yield 4-(1-(4-fluorophenyl)-1H-indazol-6-yl)butanoic acid (3, R1=4-Fluorophenyl) (15.87 g, 97%); LC/MS, method 3, Rt=2.19 min, MS m/z 299 (M+H)+. 1H NMR (400 MHz, DMSO) δ 12.03 (s, 1H), 8.30 (d, J=0.9 Hz, 1H), 7.84-7.74 (m, 3H), 7.57 (s, 1H), 7.48-7.39 (m, 2H), 7.13 (dd, J=8.3, 1.2 Hz, 1H), 2.79-2.72 (m, 2H), 2.26-2.22 (m, 2H), 1.91-1.81 (m, 2H).

Provenance & Evidence