Trifluoroacetic acid → 4-{N'-[2-(4-fluoro-phenyl)-acetyl]-N'-methyl-hydrazino}-piperidine-1-carboxylic acid tert-butyl ester

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Reaction Steps

To a solution of 4-{4-(4-fluorophenyl)-2-methyl-5-oxo-3-[2-(1-phenylethylamino)-pyrimidin-4-yl]-2,5-dihydro-pyrazol-1-yl}-piperidine-1-carboxylic acid tert-butyl ester, 26, (9 g, 15.7 mmol) in CH2Cl2 (90 mL) is added 20% TFA in CH2Cl2. After stirring at room temperature for 0.5 h, the reaction mixture is concentrated in vacuo. Purification by preparatory HPLC affords 4.2 9 (45% yield) of the desired product: [α]D −41.0° (c 1.7, MeOH); 1H NMR (300 MHz, CD3OD) δ 8.25 (d, J=4.8 Hz, 1H), 7.40-7.00 (m, 9H), 6.40 (d, J=4.8 Hz, 1H), 5.11-5.05 (m, 1H), 4.51-4.41 (m, 1H), 3.61-3.55 (m, 2H), 3.33 (bd, J=1.5 Hz, 3H), 3.24-3.05 (m, 3H), 2.92-2.75 (m, 2H), 2.19-2.10 (m, 2H), 1.52 (d, J=6.9 Hz, 3H). HRMS calcd for C27H29FN6O (M+H)+473.2465; found 473.2460.

Provenance & Evidence