2-Hydroxyisobutyric acid → 2-methyl-1-(4-{2-[3-(2-methyl-1H-benzimidazol-1-yl)-8-azabicyclo[3.2.1]oct-8-yl]ethyl}-4-phenyl-1-piperidinyl)-1-oxo-2-propanol

Participants

Reaction Steps

2-hydroxy-2-methylpropanoic acid (36 mg, 0.35 mmole) was dissolved in 0.92 ml of 1,2-dichloroethane. To this was added 1,1′-carbonyldiimidazole (37 mg, 0.23 mmole) and shaken for 30 min. 2-Methyl-1-{8-[2-(4-phenyl-4-piperidinyl)ethyl]-8-azabicyclo[3.2.1]oct-3-yl}-1H-benzimidazole (50 mg, 0.12 mmole) was added as a dry powder and shaking was resumed overnight. 1 ml of NaHCO3 sat. was added to the reaction mixture and shaken, followed by filtration through a hydrophobic frit and concentrated to an oil. The oil was separated on silica using gradient flash chromatography (0-8% MeOH in CHCl3) to afford 2-methyl-1-(4-{2-[3-(2-methyl-1H-benzimidazol-1-yl)-8-azabicyclo[3.2.1]oct-8-yl]ethyl}-4-phenyl-1-piperidinyl)-1-oxo-2-propanol 20 23.7 mg (38%) as a white glassy solid. 1H NMR (300 MHz, CDCl3) δ 7.7-7.6 (m, 1H), 7.1-7.4 (m, 8H), 4.7 (s, 1H), 4.0 (s, 2H), 3.2-3.4 (m, 4H), 2.6 (s, 3H), 2.2-2.5 (m, 5H), 2.1-1.7 (m, 11H), 1.7-1.5 (m, 2H).

Provenance & Evidence