Triethylamine → 4-[1-(5-Hydroxymethyl-4-trifluoromethyl-pyrimidin-2-yl)-piperidin-4-ylideneaminooxy]-piperidine-1-carboxylic acid isopropyl ester

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Reaction Steps

Half of the crude 57b was combined with triethylamine (50 μL, 0.36 mmol) in 2 mL of THF and treated at 0° C. with ethyl chloroformate (30 μL, 0.31 mmol). The mix was stirred at room temperature for 4 h then it was added to a stirred suspension of sodium borohydride (32 mg, 0.84 mmol) in water and the stirring was continued for 3 h. The mixture was quenched with aqueous NaHCO3 (5 mL) and water (5 mL) and extracted with EtOAc (3×5 mL). The combined extracts were dried and concentrated and the residue was purified by preparative HPLC to afford 58-1: LC-MS 460.1 (MH+), tR=7.49 (Method 2).

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