[O-]CC.[K+:4].[C:5]([O:12][CH2:13][CH3:14])(=[O:11])[C:6]([O:8]CC)=O.[Cl:15][C:16]1[C:21]([N+:22]([O-:24])=[O:23])=[C:20]([CH3:25])[CH:19]=[CH:18][N:17]=1>C(OCC)C>[Cl:15][C:16]1[C:21]([N+:22]([O-:24])=[O:23])=[C:20](/[CH:25]=[C:6](\[O-:8])/[C:5]([O:12][CH2:13][CH3:14])=[O:11])[CH:19]=[CH:18][N:17]=1.[K+:4]To a heterogeneous solution of potassium ethoxide (6.56 g, 77.9 mmol) in diethyl ether (55 mL), was slowly added diethyl oxalate (10.6 mL, 77.9 mmol). A slight exotherm resulted. After stirring 5 min, a homogeneous yellow solution resulted, but after 10 min, a heterogeneous yellow slurry was observed. Addition of 2-chloro-4-methyl-3-nitropyridine (13.45 g, 77.9 mmol) as a solid, with a diethyl ether rinse (23 mL), resulted in a dark violet solution with a dark precipitate. The mixture was stirred at room temperature overnight (21 h). The solid precipitate was filtered, rinsed thoroughly with diethyl ether, and air-dried to give potassium (1Z)-1-(2-chloro-3-nitropyridin-4-yl)-3-ethoxy-3-oxoprop-1-en-2-olate (19.8 g, 63.6 mmol, yield 81%) as an orange solid. The crude product was used directly without further purification or identification.
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