4,5-Dichloro-1,2-phenylenediamine → 6,7-dichloro-3-aminoquinoxalin-2(1H)-one

Participants

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 4,5-dichloro-1,2-phenylenediamine (354 mg, 2.00 mmol; Aldrich Co.) and ethyl thiooxamate (333 mg, 2.50 mmol; Aldrich Co.) in 5 mL of ethanol was heated to reflux. The resulting brown solution was stirred under reflux for 10 h. The resulting brown suspension was cooled down to 25° C. A brown precipitate appeared. The mixture was vacuum filtered and the brown solid was washed with EtOH (5×2 mL) and dried in vacuum at 60° C. overnight to yield 92 mg (20%) of 6,7-dichloro-3-aminoquinoxalin-2(1H)-one: mp dec.>350° C. 1H NMR (300 MHz, DMSO-d6) δ 12.261 (br s, 1H, NH), 7.421 (s, 1H, H-5), 7.252 (s, 1H, H-8). Mass: calcd. for C8H5Cl2N3O (M+) M/z 228.9810, found 228.9820.

Provenance & Evidence