Oxalic Acid → 5-Nitro-7-trifluoromethyl-1,4-dihydro-2,3-quinoxalinedione

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Reaction Steps

A suspension of 3-nitro-5-trifluoromethyl-1,2-phenylenediamine (0.560 g, 2.53 mmol) and oxalic acid (0.325 g, 2.58 mmol) in 2N HCl (8.5 mL) was refluxed for 6 h. The suspension was then cooled to r.t. and the solid filtered, washed with water (5.0 mL) and dried under vacuum to yield 0.502 (72%) of pure title compound as a yellow brown powder, m.p. 329°-332° C.; 1H NMR (DMSO-d6): 7.640 (s, 1H), 8.111 (s, 1H), 11.414 (s, 1H), 2.432 (1H).

Provenance & Evidence