tert-Butyl 4-(2-oxo-2,3-dihydro-1H-indol-1-yl)piperidine-1-carboxylate → 1-Piperidin-4-yl-1,3-dihydro-2H-indol-2-one

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Reaction Steps

4-(2-Oxo-2,3-dihydro-indol-1-yl)-piperidine-1-carboxylic acid tert-butyl ester (3.9 g, 12.3 mmol) was set stirring in 30 mL of 1:1 TFA/CH2Cl2. After 45 min the solvent was evaporated under reduced pressure to give a clear purple oil. The oil was brought up in diethyl ether and cooled on ice to give a precipitate. The solid was filtered, washed with ether and air dried to give 4.0 g (100%) of the title compound as a TFA salt. 1H NMR (400 MHz, DMSO-d6): 8.6 (br s, 1H), 7.27 (m, 3H), 7.03 (m, 1H), 4.45 (m, 1H), 3.56 (s, 2H), 3.42 (m, 2H), 3.09 (m, 2H), 2.53 (m, 2H), 1.78 (m, 2H).

Provenance & Evidence