Hydrochloric Acid → 1-(3-Isopropyl-1,2,4-oxadiazol-5-YL)piperidin-4-OL

Participants

Reaction Steps

To a solution of 4-hydroxypiperidine-1-carbonitrile (1 g, 7.93 mmol) and N-hydroxyisobutyrimidamide (0.972 g, 9.51 mmol) in ethyl acetate (40 mL) was added zinc chloride (1 M in Et2O, 9.5 mL, 9.5 mmol) dropwise at rt under argon. Precipitate formed immediately, and the reaction mixture was stirred at rt for 30 min. The solid was collected via filtering, rinsed several times with ether. The solid was dissolved in concentrated HCl (4 mL, 132 mmol), diluted with ethanol (8 mL), and refluxed for 1 h. The reaction mixture was cooled to rt and filtered. The filtrate was concentrated to approximately half of the volume, and diluted with water (15 mL). The solution was basified with solid Na2CO3, followed by extraction with CH2Cl2 (3×30 mL). The combined organic layers were washed with saturated NaHCO3 (60 mL) and brine. It was dried (Na2SO4), filtered, and concentrated. The residue was purified by column chromatography (hexanes-EtOAc gradient 0-50% EtOAc) to afford 1-(3-isopropyl-1,2,4-oxadiazol-5-yl)piperidin-4-ol (0.59 g, 2.79 mmol, 35% yield) as a clear colorless oil. 1H NMR (400 MHz, CDCl3) δ ppm 1.29 (d, J=7.07 Hz, 6H) 1.55 (d, 1H) 1.60-1.70 (m, J=12.98, 8.61, 8.61, 4.17 Hz, 2H) 1.93-2.02 (m, 2H) 2.89 (spt, J=6.95 Hz, 1H) 3.38 (ddd, J=13.20, 9.03, 3.79 Hz, 2H) 3.88-4.04 (m, 3H). LCMS (m/z)=212 (M+H)+.

Provenance & Evidence