Abstract
Synthesis of 8-alkyladenosines and related nucleosides is described. Treatment of 5'-O-acetyl-2', 3'-O-isopropylidene-8-methylsulfonyladenosine with ethyl sodioacetoacetate gave the 8-ethoxy-carbonylmethyl derivative (1). Hydrolytic decarboxylation of 1 followed by deacetonation afforded 8-methyladenosine (2) in high yield. Alkylation of 1 with methyl or ethyl iodide followed by hydrolytic decarboxylation afforded 8-ethyl- and 8-propyladenosines, respectively. Attempts at dimethylation of the 8-methylene group of 1 resulted in the formation of the N6-dimethyladenosine derivative. Selective dimethylation of the amino groups of 2'-deoxyadenosine and 2'-deoxycytidine has been accomplished by using a combination of methyl iodide and sodium hydride without methylation of the sugar hydroxyl groups of these nucleosides. 8, 2'-Anhydro-9-β-D-arabinofuranosyl-8-hydroxymethyladenine was prepared from a 8-cyanoadenosine derivative by the procedure involving anhydro-bond formation by base treatment of 8-hydroxymethyl-2'-Otosyladenosine. The circular dichroism spectral characteristics of 8-alkyladenosines are discussed.
