[CH3:1][N:2]1[C:10]([C:11]2[CH:16]=[CH:15][CH:14]=[CH:13][CH:12]=2)=[CH:9][C:8](=[O:17])[C:4]([C:5]([OH:7])=[O:6])=[C:3]1[C:18]1[CH:23]=[CH:22][CH:21]=[CH:20][CH:19]=1.[OH-].[Na+].[Br:26]Br>CO.O>[Br:26][C:9]1[C:8](=[O:17])[C:4]([C:5]([OH:7])=[O:6])=[C:3]([C:18]2[CH:23]=[CH:22][CH:21]=[CH:20][CH:19]=2)[N:2]([CH3:1])[C:10]=1[C:11]1[CH:16]=[CH:15][CH:14]=[CH:13][CH:12]=13.75 gms of 1-methyl-2,6-diphenyl-4-oxonicotinic acid was dissolved in 40 mls of methanol. The pH was adjusted to 12 with the addition of aqueous NaOH. A methanolic solution of bromine (2.95 gms Br2 in 50 mls methanol) was added. Additional NaOH was added as required to maintain a basic medium. Removal of the solvent yielded a semi-solid that was taken up in 100 mls of water. Water insoluble material was removed by filtration. Acidification of the aqueous solution provided 3.0 gms of 5-bromo-1-methyl-2,6-diphenyl-4-oxonicotinic acid (mp 242°-3°, with decomposition) as a white solid.
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