A NOVEL SYNTHESIS OF 1,6-DIAMINO-2-PYRIDONES AND [1,2,4]TRIAZOLO[1,5-A]PYRIDINE DERIVATIVES

3-Cyano-1,6-diamino-2-pyridone derivatives (3) possessing various alko xycarbonyl groups are prepared directly from the reaction of dialkyl ( E)-2,3-dicyanobutendioates (1) with cyano-acetohydrazide (2). The resu lting diamine (3) (R = Et) is readily cyclized to 8-substituted [1,2,4 ]triazolo[1,5-a]pyridine derivatives (5) in high yields by treatment w ith orthocarboxylic esters (4) such as trimethyl orthoformate or triet hyl orthoacetate etc. Furthermore, 3-cyano-6-amino-2-pyridones (6) are although obtained in excellent yields by the reductive deamination of 3. The structural study of 6 was carried out by spectroscopic methods in some details.