Trimethylsilyldiazomethane → methyl 1H-indazole-4-carboxylate

Reaction equation

[NH:1]1[C:9]2[CH:8]=[CH:7][CH:6]=[C:5]([C:10]([OH:12])=[O:11])[C:4]=2[CH:3]=[N:2]1.[CH3:13][Si](C=[N+]=[N-])(C)C>CO.C1(C)C=CC=CC=1>[CH3:13][O:11][C:10]([C:5]1[C:4]2[CH:3]=[N:2][NH:1][C:9]=2[CH:8]=[CH:7][CH:6]=1)=[O:12]

Participants

Procedure

Indazole-4-carboxylic acid (2.00 g, 12.3 mmol) was suspended in methanol (20 mL) and toluene (30 mL) at room temperature. A solution of 2 M trimethylsilyl diazomethane (12 mL, 24 mmol) in toluene was added slowly and the mixture was stirred at room temperature until the solution turned yellow. The reaction was quenched with concentrated acetic acid (5 mL) and the solvent was removed in vacuo. The residue was purified by silica gel chromatography eluting with a gradient of 0-30% ethyl acetate in hexanes to afford 1H-indazole-4-carboxylic acid methyl ester.