Toluene → ethyl 1-(4-bromophenyl)-5-methyl-1H-pyrazole-4-carboxylate
Reaction equation
S(Cl)(Cl)=O.[Br:5][C:6]1[CH:11]=[CH:10][C:9]([N:12]2[C:16]([CH3:17])=[C:15]([C:18]([OH:20])=[O:19])[CH:14]=[N:13]2)=[CH:8][CH:7]=1.[C:21]1(C)C=CC=C[CH:22]=1>>[CH2:21]([O:19][C:18]([C:15]1[CH:14]=[N:13][N:12]([C:9]2[CH:8]=[CH:7][C:6]([Br:5])=[CH:11][CH:10]=2)[C:16]=1[CH3:17])=[O:20])[CH3:22]Participants
4
Procedure
Toluene (40 ml) and thionyl chloride (8.0 ml) were added to 1-(4-bromophenyl)-5-methyl-1H-pyrazole-4-carboxylic acid (20.50 g) described in reference Example 13, stirred under reflux and the solvent was evaporated in vacuo. Pyridine (20 ml) and ethanol (40 ml) were added to the residue, and the mixture was stirred again under reflux and then the solvent was evaporated in vacuo. A saturated aqueous solution of sodium bicarbonate was added to the residue, and the mixture was extracted with ethyl acetate and the organic layer was washed with saturated brine, dried over anhydrous magnesium sulfate and concentrated in vacuo. The resulting solid was washed with n-hexane to give 1-(4-bromophenyl)-5-methyl-1H-pyrazole-4-carboxylic acid ethyl ester (15.83 g).