Formic Acid → 2-(7-fluoro-1H-benzimidazol-1-yl)ethanol

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Reaction Steps

2-[(2-fluoro-6-nitrophenyl)amino]ethanol (18.3 g, 91.5 mmol) dissolved in 90 mL of formic acid is added to a suspension of Pd—C 10% (300 mg) in 10 ml of formic acid. The mixture is shaken in a Parr apparatus under atmospheric pressure of H2 overnight. The reaction mixture is filtered over Celite, the solvent is evaporated under vacuum and the resulting residue dissolved in NH3 2M in ethanol. This solution is stirred at room temperature for 1 h (to cleave the formic acid adduct). A precipitate forms. This mixture is evaporated to dryness and purified by column chromatography (SiO2, DCM/MeOH 10:1 to 5:1), giving the desired product as a white solid (10.5 g, 64%) TLC: DCM/MeOH 5:1, Rf=0.23.

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