O-Phenylenediamine → 2(1H)-Quinoxalinone, 3,4-dihydro-

Participants

Reaction Steps

A solution of ethyl bromoacetate (III, 13.3 ml) in THF (50 ml) is added over 2 hr to a stirred solution of 1,2-phenylenediamine (II, 10.0 g) and triethylamine (16.8 ml) in THF (22 ml) and methylene chloride (22 ml). The mixture is heated at 60° for 3 hr, and is concentrated. The resulting solids are suspended and shaken vigorously in hexane (250 ml) and water (150 ml). The hexane layer is decanted, and the process is repeated with two additional 250 ml portions of hexane. The solids are filtered, dried and recrystallized from methylene chloride/hexane to give the desired product as a solid. The concentrated filtrate is purified by flash chromatography eluting with ethyl acetate/methylene chloride (25/75) to give additional title compound, mp 135°-136°: NMR (CDCl3) 8.30, 6.85-6.95, 6.65-6.80, 4.00 and 3.86 δ.

Provenance & Evidence