Abstract The syntheses of 8-aminoimidazo [4′, 5′: 5, 6] pyrido [2, 3-d] pyrimidines (7), stretched-out versions of the naturally occuring nucleoside base adenine, are reported. Their preparation involves conversion of purine into 5-arninoimidazo [4, 5-b] pyrimidine-6- carbonitrile (1) by reaction with malononitrile, followed by construction of the pyrimidine ring in two steps via the ethoxymethylene derivative 3. 8-Azapurine can be converted to 8- ...
![1H-Imidazo[4,5-b]pyridine-6-carbonitrile,5-amino- (9CI) Structure](https://image.chemsrc.com/caspic/160/50738-98-2.png)