[NH2:1][C:2]1[CH:3]=[N:4][C:5]([O:8][CH3:9])=[CH:6][CH:7]=1.[CH2:10]([O:12][C:13](=[O:24])[C:14](=[CH:20]OCC)[C:15]([O:17][CH2:18][CH3:19])=[O:16])[CH3:11].C(O)C>C1(C)C=CC=CC=1>[CH2:10]([O:12][C:13](=[O:24])[C:14](=[CH:20][NH:1][C:2]1[CH:3]=[N:4][C:5]([O:8][CH3:9])=[CH:6][CH:7]=1)[C:15]([O:17][CH2:18][CH3:19])=[O:16])[CH3:11]A solution of 3-amino-6-methoxy-pyridine (200.0 g, 1611.05 mmol, 1.0 eq) and 2-ethoxymethylene-malonic acid diethyl ester (348.4 g, 1611.05 mmol, 1.0 eq) in toluene (650 mL) is heated to reflux and the ethanol formed is removed by azeotropic distillation. After 2.5 hours at 115° C., the reaction mixture is cooled to room temperature, the solvent is removed and the resulting solid is washed with 500 mL of hexane then dried under vacuum to afford 2-[(6-methoxy-pyridin-3-ylamino)-methylene]-malonic acid diethyl ester as a red solid (434.0 g, 90% yield).
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