Trifluoroacetic acid → 6-Methyl-5-[(1-methylethyl)oxy]-1-(4-piperidinyl)-1,3-dihydro-2H-benzimidazol-2-one

A solution of 1,1-dimethylethyl 4-{6-methyl-5-[(1-methylethyl)oxy]-2-oxo-2,3-dihydro-1H-benzimidazol-1-yl}-1-piperidinecarboxylate (D76) (0.14 mmol, 53 mg) in dichloromethane (1 mL) was treated with trifluoroacetic acid (1 mL) under argon at room temperature and was allowed to stir for 1 h. The mixture was then concentrated under reduced pressure, the residue was treated with 10% aqueous sodium carbonate solution and extracted 3 times with ethyl acetate. The organics were combined, dried and concentrated under reduced pressure to give the title compound (118 mg, >>100%). M+H 290.3.