[F:1][C:2]([F:23])([F:22])[C:3]1[CH:17]=[C:16]([C:18]([F:21])([F:20])[F:19])[C:6]2[NH:7][C:8]([CH2:10][C:11]([O:13]CC)=[O:12])=[N:9][C:5]=2[CH:4]=1.C1COCC1.O.[OH-].[Li+:31]>C1COCC1>[F:23][C:2]([F:1])([F:22])[C:3]1[CH:17]=[C:16]([C:18]([F:21])([F:20])[F:19])[C:6]2[NH:7][C:8]([CH2:10][C:11]([O-:13])=[O:12])=[N:9][C:5]=2[CH:4]=1.[Li+:31]A solution of ethyl 2-(5,7-bis(trifluoromethyl)-1H-benzo[d]imidazol-2-yl)acetate (250 mg, 0.74 mmol) in 4:1 THF/water (4 mL) was treated with lithium hydroxide (21 mg, 0.88 mmol), and the mixture was stirred overnight. Analysis by LC/MS indicated that the reaction was not complete, so additional lithium hydroxide (5 mg, 0.21 mmol) was added, and the mixture was stirred for 6 h. Analysis by LC/MS indicated that the reaction was still not complete, so additional lithium hydroxide (15 mg, 0.63 mmol) was added, and the mixture was stirred overnight. Analysis by LC/MS indicated that the reaction was complete. The THF was stripped in-vacuo at room temperature, and the aqueous was freeze-dried to yield 270 mg of yellow powder. This material was used as-is in the next step. 1H NMR (500 MHz, CD3OD) δ ppm 3.72 (s, 2 H) 7.54 (s, 1 H) 7.96 (s, 1 H).
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