Phosphorus oxychloride → Diethyl 6-chloro-5-nitro-2,3-pyridinedicarboxylate

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Reaction Conditions

Reaction Steps

Diethyl 1,6-dihydro-5-nitro-6-oxo-2,3-pyridinedicarboxylate (26.23 g, 0.092 mol) is partially dissolved under N2 atmosphere in 250 mL of phosphorous oxychloride and the mixture is heated to 80° C. for 15 hours. The mixture is cooled and concentrated and the resulting oil dissolved in ethyl acetate and washed with water, 10% K2CO3 and brine. The organic layer is dried over MgSO4, filtered and the solvent removed to yield a solid which is recrystallized from absolute ethanol/water to give 20.65 g of the product as a brown solid in 73.9% yield, having a melting point of 84.5°-86° C.

Provenance & Evidence