5-Amino-2-chloropyridine → 4-(6-Chloro3-pyridinylamino)-3-ethoxy-cyclobut-3-ene-1,2-dione

Participants

Reaction Conditions

Reaction Steps

5-Amino-2-chloropyridine (2.32 g, 18.0 mmol) in ethanol (50 mL) was added to a solution of 3,4-diethoxy-3-cyclobutene-1,2-dione 3.07 g, 18.0 mmol) in ethanol (200 mL) at 70° C. over a period of 6 hours. The mixture was then heated at 80° C. for an additional 18 hours, filtered, and the solvents removed in vacuo. The crude product was suspended in 10% EtOH/EtOAc (30 mL) and adsorbed onto silica gel (15 g). Purification by flash chromatography on silica gel (eluted with 5% EtOH/EtOAc) provided 1.98 g of the desired product as a pale yellow powder.

Provenance & Evidence