p-Toluenesulfonic acid monohydrate → Methyl (2,5-di oxo-5,6-dihydro-4H-imidazo[1,5,4-de]quinoxalin-1(2H)-yl)acetate

Participants

Reaction Steps

A mixture of dimethyl 2,2′-(4-nitro-2-oxo-1H-benzimidazole-1,3-diyl)diacetate from Step B (270 mg, 0.84 mmol) and 10% Pd/C (50 mg) in MeOH (10 mL) was stirred under an atmosphere of hydrogen (ca. 1 atm). After 2 h, the reaction was filtered through a Celite pad and concentrated in vacuo. The crude solid was dissolved in toluene (3 mL) and p-toluenesulfonic acid monohydrate (2 mg, 0.011 mmol) was added. The mixture was heated at reflux for 30 min and then concentrated in vacuo to give the title compound. MS: m/z=262 (M+1).

Provenance & Evidence