Cl[C:2]1[C:7]([N+:8]([O-:10])=[O:9])=[C:6]([Cl:11])[N:5]=[C:4]([CH3:12])[C:3]=1[C:13]([O:15][CH2:16][CH3:17])=[O:14].CO.[CH2:20]([NH2:24])[CH2:21][CH2:22][CH3:23]>C(N(CC)CC)C>[CH2:20]([NH:24][C:2]1[C:7]([N+:8]([O-:10])=[O:9])=[C:6]([Cl:11])[N:5]=[C:4]([CH3:12])[C:3]=1[C:13]([O:15][CH2:16][CH3:17])=[O:14])[CH2:21][CH2:22][CH3:23]139.5 g. of 4,6-dichloro-2-methyl-5-nitropyridine-3-carboxylic acid, ethyl ester (0.5 Mol.) are dissolved in about 500 ml. of methanol. 60 g. of triethylamine are added and the solution is heated at reflux temperature. At this point, 36.5 g. of n-butylamine are added dropwise. After the addition is completed, the heating is continued for ten minutes. The solvent is then removed in vacuo and 500 ml. of ethyl acetate are added to the residue. The triethylamine hydrochloride is filtered off and the solvent evaporated. The resulting yellow oil is crystallized with 300 ml. of methanol to give 4-butylamino-6-chloro-2-methyl-5-nitropyridine-3-carboxylic acid, ethyl ester, yield 110 g. (70%), m.p. 33°-35° (methanol).
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