[H-].[Na+].[N:3]1[CH:8]=[CH:7][CH:6]=[C:5]([CH2:9][OH:10])[CH:4]=1.[CH:11]([CH:14]1[C:19]2[N:20]=[CH:21][NH:22][C:18]=2[CH2:17][CH2:16][N:15]1[C:23](OCC(Cl)(Cl)Cl)=[O:24])([CH3:13])[CH3:12]>C1COCC1>[CH:11]([CH:14]1[C:19]2[N:20]=[CH:21][NH:22][C:18]=2[CH2:17][CH2:16][N:15]1[C:23]([O:10][CH2:9][C:5]1[CH:4]=[N:3][CH:8]=[CH:7][CH:6]=1)=[O:24])([CH3:13])[CH3:12]NaH (0.19 g, 4.80 mmol, 60% dispersion in mineral oil) was suspended in anhydrous THF (5 mL), the suspension cooled to 0° C. and 3-pyridylcarbinol (0.40 mL, 4.00 mmol) was added. The suspension was stirred at 0° C. for 30 min and then added to a solution of Intermediate 2 (1.33 g, 4.00 mmol, 70% pure) in THF (10 mL) and the reaction mixture was stirred at room temperature. Two additional such portions of NaH and 3-pyridylcarbinol in THF were added after 7 and 25 h, respectively. After 4 d the reaction mixture was quenched with water (10 mL) and the solvents were removed in vacuo. The residue was dissolved in EtOAc (100 mL) washed with 1 M aq Na2CO3 solution (4×100 mL), dried (MgSO4) and the solvents were removed in vacuo. The residue was purified by column chromatography (normal phase, 20 g, Strata SI-1, silica gigatube, DCM (200 mL) followed by 2%, 4%, 5% and 10% MeOH in DCM (200 mL each)) and reverse phase HPLC (Phenomenex Synergi, RP-Hydro 150×10 mm, 10 μm, 15 mL/min, gradient 0% to 80% (over 12 min) to 100% (over 3 min) MeOH in water (1% formic acid) and Phenomenex Synergi, RP-Hydro 150×10 mm, 10 μm, 15 mL/min, gradient 0% to 40% (over 12 min) to 100% (over 3 min) MeOH in water (1% formic acid)). The residue was de-salted using K2CO3 in DCM to give pyridin-3-ylmethyl 4-isopropyl-1,4,6,7-tetrahydro-5H-imidazo[4,5-c]pyridine-5-carboxylate (46.3 mg, 3.8%) as a white solid.
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