[NH2:1][C:2]1[N:6]([CH3:7])[N:5]=[C:4]([OH:8])[C:3]=1[C:9]1[CH:14]=[CH:13][C:12]([CH3:15])=[CH:11][CH:10]=1.C(=O)([O-])[O-].[K+].[K+].[C:22]([O:25][CH2:26][CH2:27]Br)(=[O:24])[CH3:23]>CN(C)C=O.O>[C:22]([O:25][CH2:26][CH2:27][O:8][C:4]1[C:3]([C:9]2[CH:14]=[CH:13][C:12]([CH3:15])=[CH:11][CH:10]=2)=[C:2]([NH2:1])[N:6]([CH3:7])[N:5]=1)(=[O:24])[CH3:23]To 5-amino-1-methyl-4-(4-methylphenyl)-1H-pyrazol-3-ol (Preparation 3a) (250 mg) in dimethyl formamide (5 ml) at room temperature was added potassium carbonate (510 mg) and 2-bromoethyl acetate (205 mg), the mixture was stirred for 16 hrs. The reaction was diluted with water (60 ml) and extracted with ethyl acetate (3×30 ml). The organic fractions were combined, washed with water (2×30 ml) and brine (30 ml) and dried over magnesium sulfate, filtered concentrated under reduced pressure. The residue was purified by column chromatography (silica, 30 g) eluted with ethyl acetate:hexane (1:1) to yield the title compound as a white solid (151 mg).
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