Lithium Hydroxide → 5-(5-Cyanopyridin-3-ylethynyl)-2-fluorobenzoic acid

Participants

Reaction Steps

Add lithium hydroxide to a solution of 5-(5-cyanopyridin-3-ylethynyl)-2-fluorobenzoic acid methyl ester, (prepared as described in EXAMPLE 121), (890 mg, 3.18 mmol) in 3:1 tetrahydrofuran:water (50 mL) and stir for 1 h. Dilute the reaction mixture with diethyl ether and water and separate the layers. Adjust the pH of the aqueous layer to approximately pH=2 by dropwise addition of concentrated hydrochloric acid and then extract it three times with diethyl ether and three times with ethyl acetate. Extract the combined organic layers with an aqueous saturated solution of sodium chloride, dry (sodium sulfate), filter and concentrate. Recrystallize the resulting residue using ethyl acetate and methanol, to give the title compound as a white solid (658 mg, 78%).

Provenance & Evidence