SYNTHESES OF 8-AMINOIMIDAZO[4',5'/5,6]PYRIDO[2,3-D]PYRIMIDINES - LINEAR TRICYCLIC ANALOGS OF ADENINE

摘要

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-aminoimidazo[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-amino-1,2,3-triazolo[4',5':5,6]pyrido[2,3-d]pyrimidines 8 in a similar fashion. [References: 10]