To a mixture of (S)-ethyl 1-(1-(4-cyanophenyl)-2-methyl-1-oxopropan-2-yl)piperidine-3-carboxylate (90 mg, 0.274 mmol) in MeOH (5 mL) was added sodium borohydride (15 mg, 0.396 mmol). After 1 hr, the reaction was quenched with water. The reaction mixture was diluted with ethyl acetate and washed with sat NaCl. The organic layer was dried MgSO4, filtered, and concentrated. To a mixture of hydroxylamine hydrochloride (38.1 mg, 0.548 mmol) and sodium bicarbonate (92 mg, 1.096 mmol) in 2-propanol (10 mL) was added the crude product from step one. The reaction mixture was heated at 75° C. overnight. The reaction mixture was diluted with ethyl acetate and washed with H2O. The organic layer was dried MgSO4, filtered, and concentrated to yield 100 mg of (3S)-ethyl 1-(1-hydroxy-1-(4-((Z)—N′-hydroxycarbamimidoyl)phenyl)-2-methylpropan-2-yl)piperidine-3-carboxylate. MS (m+1)=364. HPLC Peak RT=0.27 minutes (Analytical Method B).
