Toluene → 2(1H)-Quinoxalinone

Participants

Reaction Conditions

Reaction Steps

To a stirred suspension of o-phenylenediamine (50 g, 462.9 mmol) in ethanol (200 mL), at rt was added a solution of ethyl glyoxalate in toluene (50%; 113 mL, 555.48 mmol) over a period of 45 min. After heating to 45° C. for 10 h, the mixture was left at rt under stirring. The precipitate was filtered and the residue was washed with water and dried to give 1H-quinoxalin-2-one as an off-white powder (63 g, 93%): 1H-NMR (300 MHz, d6-DMSO): δ=12.44 (1H, s), 8.19 (1H, s), 7.78 (1H, d), 7.55 (1H, dd), 7.32 (2H, m) ppm.

Provenance & Evidence