Cl.[CH2:2]([O:4][NH2:5])[CH3:3].C([O:8][C:9]([C:11]1[C:16]([NH:17][C:18]2[CH:23]=[CH:22][C:21]([S:24][CH3:25])=[CH:20][C:19]=2[F:26])=[C:15]([CH3:27])[N:14]2[N:28]=[CH:29][CH:30]=[C:13]2[N:12]=1)=O)C.C[Si]([N-][Si](C)(C)C)(C)C.[Li+]>C1COCC1>[CH2:2]([O:4][NH:5][C:9]([C:11]1[C:16]([NH:17][C:18]2[CH:23]=[CH:22][C:21]([S:24][CH3:25])=[CH:20][C:19]=2[F:26])=[C:15]([CH3:27])[N:14]2[N:28]=[CH:29][CH:30]=[C:13]2[N:12]=1)=[O:8])[CH3:3]O-Ethyl-hydroxylamine HCl salt (2.50 equivalents) is added to a solution of 6-(2-fluoro-4-methylsulfanyl-phenylamino)-7-methylpyrazolo[1,5-a]pyrimidine-5-carboxylic acid ethyl ester (1.00 equivalent) in THF. The solution is cooled to 0° C. and lithium bis(trimethylsilyl)amide (6.00 equivalents, 1.0 M solution in hexanes) is added dropwise. The reaction mixture is warmed to room temperature. After stirring for 1 hour, the reaction is quenched by addition of a saturated aqueous solution of NaHCO3 and partitioned between EtOAc and brine. The aqueous layer is re-extracted with EtOAc. The combined organic extracts is dried (MgSO4) and concentrated. The product is purified by flash chromatography as necessary.
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