Diethyl Oxalate → 2,3-Dihydroxy-6,7-dichloroquinoxaline

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Reaction Steps

A mixture of 4,5-dichlorophenylenediamine (54 g, 305 mmol) and diethyl oxalate (124 mL, 146.1 g, 920 mmol) was refluxed overnight, cooled to room temperature, and filtered. The residue was washed with ethanol and dried in vacuo to give the title product as a gray solid powder (67.5 g, 96%); mp>320° C.; IR (KBr, cm−1) 3188, 3156, 3057, 2918, 1724, 1693, 1613, 1497, 1452, 1340, 1338, 1250, 1131, 877, 811, 676, 669, 565; 1H NMR (DMSO) δ 12.00 (s, 2H), 7.18 (s, 2H); 13C NMR (DMSO) δ 154.8, 126.0, 124.4, 116.0; MS (ACPI), m/z 231.0 (M+); Anal. Calcd for C8H4N2O2Cl2: C, 41.59; H, 1.75; N, 12.12. Found: C, 41.60; H, 1.85; N, 12.05.

Provenance & Evidence