Synthesis and properties of 8-pyridylpurines

Abstract

8-Pyridylpurines were synthesised by condensation of 4,5-diaminopyrimidines with amidinopyridines. Protonation of the pyridine nitrogen causes a marked bathochromic shift of λ_max. in the 2′- and 4′-pyridyl derivatives, but not in the 3′-pyridyl isomers. A similar effect is produced by quaternisation of the 4′-, but not of the 3′-pyridyl substituent, while quaternisation of 8-2′-pyridylpurines has not been achieved so far. The 8-1′-methylpyridinium group also greatly facilitates anion formation in the purine ring.