Oxalic Acid → 6-Chloro-5,7-difluoro-1,4-dihydroquinoxaline-2,3-dione

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Reaction Steps

A mixture of 230 mg (1.29 mmol) of 4-chloro-3,5-difluoro-1,2-phenylenediamine and 125 mg (1.38 mmol) of oxalic acid in 4 mL of 2N HCl was refluxed for 3 h and cooled to room temperature. The mixture was filtered, washed with water, and dried to leave a brown solid (245 mg, 82%); mp >250° C.; 1H NMR (DMSO-d6), 6.921 (d, 1, J=9.61), 12.143 (s, 1), 12.168 (s, 1). MS, 232 (M+, 100), 204 (80), 176 (40), 149 (70), 171 (80). HRMS calcd for C8H335ClF2N2O2, 231.9848, found 231.9851.

Provenance & Evidence