[Cl:1][C:2]1[N:7]2[N:8]=[C:9]([C:12]3[CH:17]=[CH:16][CH:15]=[C:14]([Cl:18])[CH:13]=3)[C:10]([CH3:11])=[C:6]2[N:5]=[C:4]([CH3:19])[C:3]=1[CH:20]([OH:26])[C:21]([O:23][CH2:24][CH3:25])=[O:22].CC(OI1(OC(C)=O)(OC(C)=O)OC(=O)C2C=CC=CC1=2)=O>C(Cl)Cl.CCOC(C)=O>[Cl:1][C:2]1[N:7]2[N:8]=[C:9]([C:12]3[CH:17]=[CH:16][CH:15]=[C:14]([Cl:18])[CH:13]=3)[C:10]([CH3:11])=[C:6]2[N:5]=[C:4]([CH3:19])[C:3]=1[C:20](=[O:26])[C:21]([O:23][CH2:24][CH3:25])=[O:22]To a solution of ethyl 2-(7-chloro-2-(3-chlorophenyl)-3,5-dimethylpyrazolo[1,5-a]pyrimidin-6-yl)-2-hydroxyacetate (5.4 g, 12.33 mmol) in CH2Cl2 (100 ml) was added Dess-Martin periodinane (5.75 g, 13.56 mmol). The reaction was stirred 1 hr, then diluted with EtOAc (600 mL) and washed with saturated aqueous NaHCO3 (200 mL). The organic layer was then dried (NaHSO4), filtered, and concentrated. The residue was triturate with Et2O, stirring vigorously for 30 min, collecting solids by vacuum. The semi-pure product was purified by flash silica gel column and eluted with 10-20% EtOAc in hexanes, affording the product, ethyl 2-(7-chloro-2-(3-chlorophenyl)-3,5-dimethylpyrazolo[1,5-a]pyrimidin-6-yl)-2-oxoacetate (3.5 g, 8.92 mmol, 72.4% yield) as a pale yellow solid. 1H NMR (500 MHz, CDCl3) δ: 7.89-7.86 (m, 1H), 7.78-7.73 (m, 1H), 7.45-7.41 (m, 2H), 4.45 (q, J=7.1 Hz, 2H), 2.63 (s, 3H), 2.53 (s, 3H), 1.42 (t, J=7.2 Hz, 3H). LCMS (M+H)=392.1.
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