Synthesis and quarternization of 6-(substitutedamino)-purines with antitumor activity screening

Reaction of 6-chloro-9-benzyl-8-(methylthio)purine 3 with primary amines afforded, the corresponding 6-(substitutedamino)purines 4a-g. The latter products when methylated with methyl iodide yielded smoothly N3-methyl purinium iodide salts 5a-f rather than the probable N1- and N7-derivatives. 9-Benzyl-3-methyl-6-(methylimino)-8-(methylthio)purine 8 was obtained upon treating the purinium iodide 5a with alkali. Most of the synthesized compounds were screened for their antitumor activity.