反应详情

1-(tert-Butoxycarbonyl)piperidine-4-carboxylic acid (1.00 g, 4.36 mmol), 1-hydroxybenzotriazole (589 mg, 4.36 mmol) and N-methylmorpholine (0.97 mL, 8.72 mmol) were dissolved in dicloromethane (50 mL), under argon, and (3-dimethylaminopropyl)carbodiimide hydrochloride (921 mg, 8.72 mmol) and N′-hydroxy-2-[4-(methylthio)phenyl]ethanimidamide (855 mg, 4.36 mmol) were added. The mixture was stirred at room temperature for 92 hours. The organics were washed with sodium hydroxide (0.1N) and citric acid (0.5M), dried (phase separating filter) and the solvent evaporated to give a yellow oil which was redissolved in 1,4-dioxane (100 mL) and heated to reflux for 5 hours, cooled and the solvent evaporated and chromatographed (50 g Silica Isolute, eluent 20% ethyl acetate/isohexane) to give a yellow oil, tert-butyl 4-{3-[4-(methylthio)benzyl]-1,2,4-oxadiazol-5-yl}piperidine-1-carboxylate (920 mg, 54%); NMR (CDCl3): 1.46 (9H, s), 1.71-1.87 (2H, m), 2.03 (2H, m), 2.48 (3H, m), 2.92 (2H, t), 3.05 (1H, m), 4.00 (2H, s), 4.07 (2H, m), 7.24 (4H, m).

1. washThe organics were washed with sodium hydroxide (0.1N) and citric acid (0.5M)
2. customdried
3. custom(phase separating filter)
4. customthe solvent evaporated
5. customto give a yellow oil which
6. temperatureheated
7. temperatureto reflux for 5 hours
8. temperaturecooled
9. customthe solvent evaporated
10. customchromatographed (50 g Silica Isolute, eluent 20% ethyl acetate/isohexane)