Br[C:2]1[C:3]([C:11]2[CH:16]=[CH:15][CH:14]=[C:13]([CH3:17])[N:12]=2)=[N:4][N:5]2[CH:10]=[CH:9][CH:8]=[CH:7][C:6]=12.C([Li])(C)(C)C.[B:23](OC(C)C)([O:28]C(C)C)[O:24]C(C)C>C1COCC1>[CH3:17][C:13]1[N:12]=[C:11]([C:3]2[C:2]([B:23]([OH:28])[OH:24])=[C:6]3[CH:7]=[CH:8][CH:9]=[CH:10][N:5]3[N:4]=2)[CH:16]=[CH:15][CH:14]=1A solution of 3-bromo-2-(6-methyl-pyridin-2-yl)-pyrazolo[1,5-a]pyridine (PREP. 17, 0.2 g, 0.69 mmol) in THF (10 mL) is cooled to −78° C. and treated with tert-butyllithium (1.7 M in pentane, 1.6 mL, 2.8 mmol). This solution is stirred for 30 minutes at −78° C., treated with triisopropyl borate (0.39 g, 2.08 mmol), and stirred for 2 hr at −78° C. The reaction is then quenched with 1N HCl and stirred for 30 minutes at room temp. Evaporation leads to the solid crude product that is used without further purification. MS ES+ m/e 253.9 (M+1).
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