Hydrochloric Acid → 2,3-Diethyl 2,3-pyridinedicarboxylate

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Reaction Steps

A soution of dimethyl formamide (73 g, 1.00 mole) in ethylene dichloride is slowly treated with oxalyl chloride (88 mL, 1.00 mole), with cooling, stirred at ambient temperatures for 16 hours, treated with ethyl vinyl ether (72.1 g, 1.00 mole) over a 1 hour period and stirred at ambient temperatures for 16 hours. This reaction mixture is treated sequentially with diethyl oxalacetate (199.28 g, 1.06 mole) and (with cooling) triethylamine (224 g, 2.2 mole), stirred for 0.5 hours and treated with a premixed solution of concentrated HCl (200 ml) and concentrated NH4OH (200 ml) in 100 ml of water. The reaction mixture is treated further with water (250 ml), concentrated NH4OH (70 ml) and acetic acid (200 ml). The resultant mixture is distilled under N2 at 88° C. and atmosphere pressure to remove 1850 g of distillate. The distillation pot is then treated with absolute ethanol (1.0 L) and NH4OCOCH3 (180 g), heated at reflux temperature for 16 hours and distilled at 100° C. to remove 887 g of distillate. The distillation pot is cooled and the residue is partitioned between water and 2:1 ethyl acetate/hexanes. The organic phase is separated, washed sequentially with water and brine and concentrated in vacuo to give the title product as an oil, 179.5 g, (77% pure) 58.5% yield, identified by NMR analysis.

Provenance & Evidence