Reaction of pyrazine-2,3-dicarbonitrile and 1,3-dimethyllumazine with the phthalimidoalkyl radical

A phthalimidoalkyl radical reacts with pyrazine-2,3-dicarbonitrile ( 1 ) to give mono- and diphthalimido-alkylpyrazine-2,3-dicarbonitriles 4 and 5 . A similar reaction with 1,3-dimethyllumazine ( 2 ) gave only monophthalimidoalkyl-1,3-dimethyllumazines 6 or 7 . Hydrazine degradation of 7-(3′-phthalimido)propyl-1,3-dimethyllumazine ( 6c ) gave a 7-(3′-amino)propyl derivative 8 but 7-phthalimidomethyl-1,3-dimethyllumazine ( 6a ) gave only 1,3-dimethyllumazine ( 2 ). Thus the phthalimidomethyl group can be used as a protection group of the pteridine nucleus.