C[O:2][C:3]([C:5]1[CH:10]=[CH:9][C:8]([NH:11][CH2:12][C:13]2[CH:18]=[CH:17][CH:16]=[CH:15][CH:14]=2)=[CH:7][N:6]=1)=[O:4].[CH2:19]=O>C(O)=O>[CH3:19][N:11]([C:8]1[CH:9]=[CH:10][C:5]([C:3]([OH:2])=[O:4])=[N:6][CH:7]=1)[CH2:12][C:13]1[CH:18]=[CH:17][CH:16]=[CH:15][CH:14]=1The mixture of 4.84 g of 5-benzylaminopyridine-2-carboxylic acid methyl ester, 8 ml of 97% aqueous formic acid and 8 ml of 37% aqueous formaldehyde is heated on a steam bath for 22 hours. It is evaporated, the residue dissolved in water and the solution again evaporated. A third such cycle with acetonitrile-toluene yields a solid which is recrystallized from 90% aqueous acetonitrile, to yield the 5-(N-methyl-N-benzylamino)-pyridine-2-carboxylic acid melting at 168°-173°.
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