CC(C)=[O:3].OS(O)(=O)=O.O=[Cr](=O)=O.[CH2:14]([O:16][C:17]([C:19]1[CH:29]=[C:22]2[C:23]([CH2:27][OH:28])=[CH:24][CH:25]=[CH:26][N:21]2[N:20]=1)=[O:18])[CH3:15].CC(C)=O>C(O)(C)C>[CH3:15][CH2:14][O:16][C:17]([C:19]1[CH:29]=[C:22]2[C:23]([C:27]([OH:3])=[O:28])=[CH:24][CH:25]=[CH:26][N:21]2[N:20]=1)=[O:18]A 2.65 M solution of the Jones reagent (28 mL) is added dropwise over 40 min to a solution of 4-hydroxymethylpyrazolo[1,5-a]pyridine-2-carboxylic acid ethyl ester (5.30 g, 24.1 mmol) and acetone (240 mL) under air cooled by a water bath. After 20 min, isopropanol (3 mL) is added dropwise. After stirring for 30 min, the blue-green mixture is filtered (acetone rinse). The organics are concentrated under reduced pressure. The residue is dissolved in water. Et2O is added and the mixture is stirred for 15 min. The resulting solid is collected by filtration. The filtrate is dried to afford the title compound as a tan solid. LC-MS m/z (M+Na+): 257.02§.
Wird geladen…