C1(OC([N:10]2[CH2:15][CH2:14][CH:13]([C:16]3[CH:21]=[CH:20][CH:19]=[C:18]([O:22]C(C)C)[CH:17]=3)[CH2:12][CH2:11]2)=O)C=CC=CC=1.C(O)(=O)C.O>Br>[NH:10]1[CH2:15][CH2:14][CH:13]([C:16]2[CH:17]=[C:18]([OH:22])[CH:19]=[CH:20][CH:21]=2)[CH2:12][CH2:11]14-(3-(1-Methylethoxy)phenyl)-1-piperidine-carboxylic acid phenyl ester (Preparation 46, 1.7 g, 5.01 mmol) was heated under reflux in 47% aqueous hydrobromic acid:glacial acetic acid (1:1, 20 ml) for 16 h. The solution was allowed to cool to room temperature and water (10 ml) was added. The solution was extracted with methyl tert-butyl ether (3×10 ml) to remove phenol as a by-product. The pH was adjusted to 10.3-10.5 with 15% w:v aqueous sodium hydroxide solution and the reaction mixture was left at room temperature for 2 h to precipitate the product. After cooling to 0° C. the precipitate was filtered and washed with cold water (5 ml) to give the title compound as a solid (380 mg, 43%).
Wird geladen…
