C([O:3][C:4]([C:6]1[CH2:7][CH2:8][N:9]([CH2:19][C:20]2[CH:25]=[CH:24][CH:23]=[CH:22][CH:21]=2)[CH2:10][C:11]=1[C:12]1[CH:17]=[CH:16][C:15]([Cl:18])=[CH:14][CH:13]=1)=[O:5])C.O[Li].O>C1COCC1.O>[CH2:19]([N:9]1[CH2:10][C:11]([C:12]2[CH:13]=[CH:14][C:15]([Cl:18])=[CH:16][CH:17]=2)=[C:6]([C:4]([OH:5])=[O:3])[CH2:7][CH2:8]1)[C:20]1[CH:21]=[CH:22][CH:23]=[CH:24][CH:25]=1A mixture of 0.555 g (1.26 mmol) 1-benzyl-5-(4-chloro-phenyl)-1,2,3,6-tetrahydro-pyridine-4-carboxylic acid ethyl ester and 261 mg (6.2 mmol) LiOH.H2O in 15 mL THF and 5 mL water was stirred at room temperature over night. The mixture was evaporated to dryness, taken up in ethyl acetate, acidified with HCl to pH=1 and extracted with ethyl acetate. The combined organic layers were washed with water, evaporated to dryness and the residue was subjected to preparative HPLC chromatography on reversed phase eluting with a gradient formed from acetonitrile, water and formic acid to yield after evaporation of the product containing fractions 0.254 g (50%) of the title compound as white solid. MS (m/e): 328.2 [(M+H)+].
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