[NH:1]1[C:9]2[C:4](=[CH:5][CH:6]=[CH:7][CH:8]=2)[CH:3]=[N:2]1.C[O-].[Na+].Br[CH2:14][C:15]([OH:17])=[O:16].Cl>CO.C(OCC)(=O)C>[C:15]([CH2:14][N:1]1[C:9]2[C:4](=[CH:5][CH:6]=[CH:7][CH:8]=2)[CH:3]=[N:2]1)([OH:17])=[O:16]
To a solution of indazole (1.0 g, 8.3 mM) in methanol (10 μl) are added 28% solution of sodium methoxide in methanol (3.53 ml, 18.26 mmole) and bromoacetic acid (1.41 g, 9.96 mmole), and the mixture is heated to reflux for 2 hr. After addition of the same amount of sodium methoxide and bromoacetic acid, the mixture is heated to reflux for another 1 hr. This procedures of addition are repeated two more times and the mixture is cooled to 0° C. After addition of ethyl acetate, the mixture is adjusted to pH 5 with 1N HCl. The organic layer is taken and the aqueous layer extracted with ethyl acetate. Each organic solution is washed with a brine, dried over anhydrous magnesium sulfate and concentrated. The residue, when purified with column chromatography (SiO2, ethyl acetate→ethyl acetate/acetic acid/water, (40:1:1)→(30:1:1)→(8:1:1)), gives 1-carboxymethylindazole (487 mg, yield 33%).
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