Trifluoroacetic acid → 5-(2-fluoro-4-(1H-tetrazol-1-yl)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-(1H-tetrazol-1-yl)phenyl]benzo[d]oxazol-2-yl}piperidine-1-carboxylate (100 mg, 0.22 mmol) dissolved in DCM (25 ml) and added trifluoroacetic acid (0.4 ml). This mixture stirred at rt for 3 h. After completion of the reaction, DCM removed on rotavapour and residue was co-distilled with ether to obtain 5-[2-fluoro-4-(1H-tetrazol-1-yl)phenyl]-2-(piperidin-4-yl)benzo[d]oxazole 2,2,2-trifluoroacetate (100 mg). 5-[2-fluoro-4-(1H-tetrazol-1-yl)phenyl]-2-(piperidin-4-yl)benzo[d]oxazole 2,2,2-trifluoroacetate (100 mg, 0.21 mmol) was dissolved in DMF (3 ml) and added isobutyric acid (202 mg, 0.23 mmol), EDC.HCl (99 mg, 0.52 mmol), HOBt (33 mg, 0.25 mmol) and TEA (0.23 ml, 1.7 mmol). After completion of the reaction, work up (EtOAc/H2O) followed by purification on combiflash using the gradient mixture of EtOAc and Petether (65:35) as eluent afforded the titled compound (20 mg) as a brown solid. M.P.: 190-194° C. 1H-NMR (δ ppm, CDCl3, 400 MHz): 9.04 (s, 1H), 7.88 (s, 1H), 7.68 (t, J 8.2, 1H), 7.67-7.59 (m, 2H), 7.52 (td, J 1.6, 8.4, 1H), 4.58 (d, J 12.1, 1H), 4.04 (d, J 13.2, 1H), 3.35-3.22 (m, 2H), 2.96 (t, J 12, 1H), 2.85 (septet, J 6.8, 1H), 2.30-2.18 (m, 2H), 2.05-1.72 (m, 2H), 1.16 (d, J 6.8, 6H).

Provenance & Evidence