Trifluoroacetic acid → 5-[3-fluoro-4-(1H-tetrazol-1-yl)phenyl]-2-(piperidin-4-yl)benzo[d]oxazole 2,2,2-trifluoroacetate

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반응 단계

Tert-butyl 4-{5-[3-fluoro-4-(1H-tetrazol-1-yl)phenyl]benzo[d]oxazol-2-yl}piperidine-1-carboxylate (120 mg, 0.26 mmol) dissolved in DCM (15 ml) and added Trifluoroacetic acid (0.5 ml). This mixture was stirred at rt for 2 h. DCM removed from the reaction mixture to obtain 5-[3-fluoro-4-(1H-tetrazol-1-yl)phenyl]-2-(piperidin-4-yl)benzo[d]oxazole 2,2,2-trifluoroacetate (120 mg). 5-[3-fluoro-4-(1H-tetrazol-1-yl)phenyl]-2-(piperidin-4-yl)benzo[d]oxazole 2,2,2-trifluoroacetate (120 mg, 0.25 mmol) was dissolved in DCM (15 ml) and added TEA (0.27 ml, 2 mmol). This mixture stirred at rt for 30 mins and added isopropyl chloroformate in toluene (61 mg, 0.34 mmol). After 1 h, reaction mass diluted with water and extracted with DCM. Removal of DCM afforded crude. Crude was purified by combiflash using a mixture of EtOAc and Petether (35:65) as eluent to afford the titled compound (20 mg) as an off-white solid. M.P.: 187-191° C. 1H-NMR (δ ppm, CDCl3, 400 MHz): 9.14 (d, J 2.6, 1H), 8.02 (t, J 8.2, 1H), 7.90 (d, J 1.4, 1H), 7.63-7.55 (m, 4H), 4.95 (septet, J 6.2, 1H), 4.20 (d, J 11.2, 2H), 3.22-3.14 (m, 1H), 3.04 (t, J 11.4, 2H), 2.18 (d, J 10.8, 2H), 2.00-1.88 (m, 2H), 1.26 (d, J 6.2, 6H).

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