Preparation of novel 3,7-, 7,9- and 1,7-disubstituted guanines

Treatment of guanosine with arylmethyl halides in N,N-dimethylacetamide results in a series of 3,7-bis(arylmethyl) guanines and 7,9-bis(arylmethyl)guaninium halides. The same reaction on 7-arylmethyl guanines yields 3,7- and 7,9- differently disubstituted guanines. When 7-arylmethyl guanines are reacted with (hetero)arylmethyl halides in the presence of sodium hydride in N,N-dimethylformamide, 3,7- and 1,7-disubstituted guanines are obtained. All of these compounds, but one, are new and the preparation of 3,7-bis(substituted) guanines from guanosine as well as of 3,7- and 1,7-di(hetero)arylmethyl guanines from 7-substituted guanine is unprecedented.