Abstract
Pteridine derivatives related to folic acid and methanopterin were synthesized by two methods. The first synthesis is initiated by the radical substitution of 5‐methylpyrazine‐2,3‐dicarbonitrile (3) with the (N‐acylanilino)alkyl radical to give 6‐methyl‐5‐(N‐acylanilino)alkylpyrazine‐2,3‐dicarbonitrile (9) and was followed by the substitution of the 2‐carbonitrile with methylamine and further conversion to 1‐methyl‐2‐amino‐6‐(N‐acylanilino)‐alkyl‐7‐methylpteridin‐4(1__H__)‐imine 11 by the action of guanidine. The second method is initiated by radical hydroxymethylation of 5‐methylpyrazine‐2,3‐dicarbonitrile (3) to give 5‐hydroxy‐methyl‐6‐methylpyrazine‐2,3‐dicarbonitrile (15), followed by oxidation of the hydroxymethyl group, N‐phenylimination, and the substitution of the 2‐carbonitrile with methylamine to give 6‐methyl‐2‐methyl‐arnino‐5‐(N‐phenylimino)methenylpyrazine‐3‐carbonitrile (18). The reduction of the imino group and the final cyclization with guanidine gives 2‐amino‐6‐anilinomethyl‐1,7‐dimethylpteridin‐4(1__H__)‐imine (20).