Trifluoroacetic acid methylene chloride → 2H-1,4-Benzoxazin-3(4H)-one, 4-(4-piperidinyl)-

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Reaction Steps

4-(3-Oxo-2,3-dihydro-benzo[1,4]oxazin-4-yl)-piperidine-1-carboxylic acid tert-butyl ester (17 g, 51 mmol) and 1:1 TFA/CH2Cl2 (40 mL) were combined and set stirring. After 45 min the mixture was evaporated to give a clear brown oil. The oil was set stirring and Et2O was added (300 mL). A solid formed and was filtered, washed with Et2O and air dried to give 16 g (90%) of a light beige solid. MS (electrospray): exact mass calculated for C13H16N2O2, 232.12. m/z found, 233.1 [M+H]+. 1H NMR (400 MHz, CD3OD): 7.44 (dd, J=6.5, 1.4 Hz, 1H), 7.20-7.7.10 (m, 3H), 4.58 (s, 2H), 4.55-4.45 (m, 1H), 4.65-4.55 (m, 2H), 3.27 (dt, J=13.0, 2.3 Hz, 2H), 3.05 (dd, J=12.3, 4.1 Hz, 2H), 2.15 (d, J=13.8 Hz, 2H).

Provenance & Evidence