Diethyl Oxalate → HCID 86619018, compound

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.