215878-20-9

D. Synthesis of 3-piperidin-4-yl-3H-benzoxazol-2-one. To a stirred solution of 1.00 g (2.87 mmol) of tert-butyl 4-(2-oxobenzo[D]oxazol-3(2H)-yl)piperidine-1-carboxylate in dichloromethane (6.0 mL) was added trifluoroacetic acid (6.0 mL) and the mixture was stirred for 12 hours. After the reaction was complete, the solvent was removed under reduced pressure, the crude product was diluted with methanol (10 mL), saturated sodium bicarbonate solution (15 mL) was added to the mixture and stirring was continued for 10 minutes. The reaction mixture was diluted with dichloromethane (30 mL) and the organic and aqueous layers were separated. The aqueous phase was extracted with dichloromethane (2 x 20 mL), all organic layers were combined, dried over anhydrous sodium sulfate, and concentrated under reduced pressure to remove the solvent, yielding 1.02 g (88% yield) of light yellow solid product. Thin-layer chromatography (silica gel, 10% methanol/dichloromethane): Rf = 0.1. Mass spectrometry (electrospray): m/z calculated value C12H14N2O2, [M + H]+, 219.11, measured value 219.1.

[1] Bioorganic and Medicinal Chemistry Letters, 1998, vol. 8, # 18, p. 2467 - 2472
[2] Bioorganic and Medicinal Chemistry Letters, 2007, vol. 17, # 12, p. 3421 - 3425
[3] Patent: US2005/101587, 2005, A9