Abstract
Treating carbocyclic N1-methoxymethyl-inosine and -2′-deoxyinosine with 1N-NaOH/aq.EtOH gave carbocyclic 5-amino-4-imidazolecarboxamide riboside and 2′-deoxyriboside, respectively. Reactions of both the useful key intermediates with benzoylisothiocyanate afforded the corresponding 5-(N-benzoylisothiocarbamoyl) derivatives. Methylation of the sulfhydryl groups, followed by treatment with NaOH, led to the purine ring-closure (guanine, isoguanine, and 3-methylxanthine) reaction. The conformational difference between 2′-deoxyguanosine and carbocyclic 2′-deoxyguanosine is also discussed.