Selective N-7 alkylation of 3-methylhypoxanthine; the first synthesis of malonganenone J

3-Methylhypoxanthine has been reacted with various alkyl halides under basic conditions. Allylic and benzylic halides reacted mostly at N-7 to give dialkylated purines, however, ring-opened imidazole by-products, probably resulting from N-1 alkylation and hydrolysis of the formed salt , were often obtained in minor amounts. Less reactive halides required a larger excess, higher temperatures and longer reaction times. 3,7-Dialkylpurines were again the major products and imidazoles were formed in very minor amounts, however, considerable amount of O-alkylation also took place. The marine natural product malonganenone J was synthesized for the first time by selective N-7 alkylation of 3-methylhypoxanthine with geranylgeranyl bromide.