C(O[C:6]([NH:8][NH:9][CH2:10][C:11]1[CH:16]=[C:15]([Br:17])[CH:14]=[CH:13][C:12]=1[OH:18])=O)(C)(C)C.CCO.[CH2:22]([O:24][C:25](=[O:35])[CH2:26][C:27](=CN(C)C)[C:28](=O)[CH3:29])[CH3:23]>C(Cl)Cl.C(O)(C(F)(F)F)=O>[CH2:22]([O:24][C:25](=[O:35])[CH2:26][C:27]1[CH:6]=[N:8][N:9]([CH2:10][C:11]2[CH:16]=[C:15]([Br:17])[CH:14]=[CH:13][C:12]=2[OH:18])[C:28]=1[CH3:29])[CH3:23]A suspension of N′-(5-bromo-2-hydroxy-benzyl)-hydrazinecarboxylic acid tert-butyl ester 1 1 g (3.1 mmol) in a mixture of CH2Cl2 (8 mL) and TFA (8 mL) was stirred at RT for 2 hours. The volatiles were removed in vacuo. The residue was dissolved in abs. EtOH (7 mL) and added to 3-[1-dimethylamino-methylidene]-4-oxo-pentanoic acid ethyl ester (4.8 mmol) at RT. The resulting mixture was stirred at RT for 1 hour, refluxed for 2 h, let cool down and stirred at RT for 16 h. The oily residue obtained after removing the volatiles in vacuo was purified by MPLC (10 g SiO2 cartridge, eluent 90% iso-hexane-10% EtOAc) to give 0.18 g of [1-(5-Bromo-2-hydroxy-benzyl)-5-methyl-1H-pyrazol-4-yl]-acetic acid ethyl ester, 2.
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