Nitration of 5-chloro-2-methoxybenzonitrile (I) with 70 % HNO3 at 5?C gives the nitro derivative (II). Nucleophilic substitution of the methoxy group of (II) with sodium glycinate yields the N-arylglycinate (III). Reduction of nitro derivative (III) with Na2S2O4 followed by cyclization leads to the quinoxalin-2-one (IV). This is finally oxidized to the desired quinoxalinedione using HNO3 in trifluoroacetic acid.