Methyl iodide → 5-Methoxy-1-phenyl-1H-pyrazole-3-carboxylic acid

Reaction equation

[OH:1][C:2]1[N:6]([C:7]2[CH:12]=[CH:11][CH:10]=[CH:9][CH:8]=2)[N:5]=[C:4]([C:13]([OH:15])=[O:14])[CH:3]=1.[C:16](=O)([O-])[O-].[Cs+].[Cs+].IC>CN(C=O)C>[CH3:16][O:1][C:2]1[N:6]([C:7]2[CH:12]=[CH:11][CH:10]=[CH:9][CH:8]=2)[N:5]=[C:4]([C:13]([OH:15])=[O:14])[CH:3]=1

Participants

Procedure

600 mg (2.94 mmol) of 5-hydroxy-1-phenyl-1H-pyrazole-3-carboxylic acid were dissolved in 30 ml of DMF, 1.92 (5.9 mmol) of cesium carbonate and 1.04 g (7.35 mmol) of iodomethane were added, and the resulting mixture was heated for 4 h to 80° C. The mixture was filtrated and the solvent removed in vacuo. The residue was dissolved in 20 ml of MOH and 5.9 ml of an aqueous 1 M solution of sodium hydroxide. After stirring overnight the reaction was complete. The solvent was removed and the residue subjected to preparative HPLC to give the title compound in a yield of 38%.