Synthesis of α-(aminomethylene)-9H-purine-6-acetic acid derivatives

α-(Aminornethylene)-9H-purine-6-acetamide (3a) and the corresponding ethyl acetate 9 have been synthesized by catalytic hydrogenation of 6-cyanomethylenepurine derivatives 2 and 7 which were obtained by the substitution of 6-chloropurine derivatives with α-cyanoacetamide and ethyl cyanoacetate, respectively. Substitution of α-(aminomethylene)-9-(tetrahydrofuran)-9H-purine-6-acetamide (3b) with amines gave the corresponding N-alkyl- and N-arylamines 5, which were treated with acid to give N-substituted α-(aminomethylene)-9H-purine-6-acetamides 6. Substitution of 9 with amines gave the corresponding N-alkyl- and N-aryl substituted amines 10.