Transformations of 2-Alkoxy-6-chloro- and 6-Alkoxy-2-chloro-7-methylpurines Under the Action of Methyl Iodide

2-Alkoxy-6-chloro-7-methylpurines 3 were prepared by 6-chloro-dealkoxylation of 2,6-dialkoxy-7-methylpurines 4. Reactions of alkoxy-chloro-7-methylpurines 2 and 3 with methyl iodide led as N-9 methylation and as N-3 methylation to give N-methyl purinium salts 9 and 11 from purine 2 or 6 and 7 from purine 3. The formation of purinium salts was accompanied by 6-iodo-dechlorination leading from 3 to 6-iodopurinium salt 5 and by alkyl iodide elimination leading to hypoxanthine 10.