3-Chloro-5-(trifluoromethyl)benzene-1,2-diamine → 5-chloro-7-trifluoromethyl-3-aminoquinoxalin-2(1H)-one

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Reaction Conditions

Reaction Steps

An adaptation of the method of Burrell et al., J. Chem. Soc. Perkin I. 2707 (1973), was used. A mixture of 3-chloro-5-trifluoromethyl-1,2-phenylenediamine (420 mg, 2.00 mmol; Maybridge Co.) and ethyl thiooxamate (293 mg, 2.20 mmol; Aldrich Co.) in 4 mL of 1-butanol was heated to reflux. The resulting solution was stirred under reflux for 6 h. The resulting suspension was cool to 25° C. A pale yellow precipitate appeared. The mixture was vacuum filtered and the solid was washed with EtOH (5×2 mL) and dried in vacuum at 60° C. overnight to yield 50 mg (9.5%) of 5-chloro-7-trifluoromethyl-3-aminoquinoxalin-2(1H)-one (tentatively named as this since the regiochemistry is not sure) as a pale yellow solid: mp 270°-272° C. 1H NMR (300 MHz, DMSO-d6) δ 12.043 (br s, 1H, NH), 7.561 (s, 1H, H-7), 7.463 (s, 1H, H-5). LRMS: 263 (M+, 100%), 235 (50%).

Provenance & Evidence