C([O:3][C:4]([C:6]1([CH2:19][C:20]2[CH:25]=[CH:24][C:23]([Cl:26])=[CH:22][CH:21]=2)[CH2:11][CH2:10][CH2:9][N:8]([C:12]([O:14][C:15]([CH3:18])([CH3:17])[CH3:16])=[O:13])[CH2:7]1)=[O:5])C.[OH-].[Na+].Cl>C(O)(C)C>[C:12]([N:8]1[CH2:9][CH2:10][CH2:11][C:6]([CH2:19][C:20]2[CH:21]=[CH:22][C:23]([Cl:26])=[CH:24][CH:25]=2)([C:4]([OH:5])=[O:3])[CH2:7]1)([O:14][C:15]([CH3:17])([CH3:18])[CH3:16])=[O:13]A suspension of Ethyl-3-(4-chlorobenzyl)-N-Boc-piperidin-3-caroxylate (36.4 g, 0.105 mol) in isopropyl alcohol (300 mL) was treated with 10N NaOH (300 mL). The mixture was heated at reflux for 48 hours. The reaction was cooled to room temperature and carefully neutralized by pouting over 1 L of crashed ice and adding 6 N HCl until pH 3. The mixture was then extracted with ethyl acetate (3×500 mL). The combined organic extracts were dried over anhydrous magnesium sulfate, filtered, and concentrated at reduced pressure to give 31 g of the product. 1H NMR CDCl3 δ 10.18 (br s), 7.26 (d, J=8.5 Hz, 2H), 7.04 (d, J=8.5 Hz, 2H), 3.95 (m, 1H), 3.6 (m, 1H), 3.2 (m, 2H), 2.90 (d, J=12 Hz, 1H), 2.78 (d, J=12 Hz, 1H), 2.00 (m, 1H), 1.75-1.30 (m, 3H), 1.44 (s, 9H).
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