X-ray crystallographic proof of electrophilic attack at the pyrimidine/imidazole ring junction in guanosine

Abstract
The crystal structure of a novel nucleoside isolated from guanosine/p-methylbenzyl chloride reactions demonstrates linkage between the methylene carbon of the benzyl moiety and carbon-5 of guanosine, and loss of the carbonyl function at carbon-6 of guanosine, to yield 4-(p-methylbenzyl)-5-guanidino-1-.beta.-D-ribofuranosylimidazole. Carbon-5 of guanine in DNA is evidently a potential site of reaction for electrophilic ultimate carcinogens.