[CH2:1]([N:8]1[CH2:13][CH2:12][N:11]([C:14]2[CH:23]=[CH:22][CH:21]=[CH:20][C:15]=2[C:16]([O:18]C)=[O:17])[CH2:10][CH2:9]1)[C:2]1[CH:7]=[CH:6][CH:5]=[CH:4][CH:3]=1.[Li+].[OH-]>C1COCC1.O>[CH2:1]([N:8]1[CH2:9][CH2:10][N:11]([C:14]2[CH:23]=[CH:22][CH:21]=[CH:20][C:15]=2[C:16]([OH:18])=[O:17])[CH2:12][CH2:13]1)[C:2]1[CH:3]=[CH:4][CH:5]=[CH:6][CH:7]=1To a 150 mL round-bottomed flask equipped with magnetic stirring was added methyl 2-[4-benzylpiperazinyl]benzoate (Preparation XIII) (2.3 g, 7.4 mmol) in THF (60 mL). A soln of LiOH (Aldrich) (940 mg, 22 mmol) in H2O (20 mL), was added and the reaction mixture was heated at 60° C. for 12 h. After cooling to RT, the reaction mixture was concentrated in vacuo and diluted with EtOAc (100 mL). A 10% soln of citric acid (25 mL) was added, the organic layer was separated and the aqueous layer was extracted with EtOAc (2×25 mL). The organic layers were combined, washed with H2O, satd NaCl, dried over Na2SO4, filtered and concentrated in vacuo to afford 2-[4-benzylpiperazinyl]benzoic acid as a white solid (2.05 g). MS (ESI, pos. ion) m/z: 297 (M+H). Calc'd for C18H20N2O2: 296.15: 296.15.
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