Trifluoroacetic acid → 5-(2-Fluoro-4-(methylsulfonyl)phenyl)-2-(piperidin-4-yl)-benzo[d]oxazole 2,2,2-trifluoroacetate

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Reaction Steps

Tert-butyl 4-{5-[2-fluoro-4-(methylsulfonyl)phenyl]benzo[d]oxazol-2-yl}piperidine-1-carboxylate (200 mg, 0.42 mmol) dissolved in DCM and added Trifluoroacetic acid (0.75 ml). This mixture was stirred at rt for 2 h. DCM removed from the reaction mixture to obtain 5-(2-fluoro-4-(methylsulfonyl)phenyl)-2-(piperidin-4-yl)benzo[d]oxazole 2,2,2-trifluoroacetate (190 mg). 5-(2-fluoro-4-(methylsulfonyl)phenyl)-2-(piperidin-4-yl)-benzo[d]oxazole 2,2,2-trifluoroacetate (190 mg, 0.39 mmol) was dissolved in DCM (20 ml) and added TEA (0.43 ml, 3.12 mmol). This mixture stirred at rt for 30 mins and added isopropyl chloroformate in toluene (0.095 g, 0.78 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 (120 mg) as a pale-yellow solid. M.P.: 96.5-101.2° C. 1H-NMR (δ ppm, CDCl3, 400 MHz): 7.87 (s, 1H), 7.81 (dd, J 1.7, 8, 1H), 7.80-7.75 (m, 1H), 7.67 (t, J 7.5, 1H), 7.59 (d, J 8.4, 1H), 7.50 (d, J 8.5, 1H), 4.94 (septet, J 6.2, 1H), 4.19 (d, J 10.9, 2H), 3.22-3.13 (m, 1H), 3.12 (s, 3H), 3.04 (t, J 10.9, 2H), 2.22-2.14 (m, 2H), 2.00-1.88 (m, 2H), 1.26 (d, J 6.2, 6H).

Provenance & Evidence