SYNTHESIS OF 5-AMINO-1-(3′-DEOXY-β-D-RIBOFURANOSYL)-4-IMIDAZOLETHIOCARBOXAMIDE

As an interesting analog of thio-AICA-riboside (5-amino-1-β-D-ribofuranosyl-4-imidazolethiocarboxamide), 3'-deoxy-thio-AICA-riboside (XV) was prepared. 5'-Acetyl-AICA-riboside (X) synthesized from Ip-AICA-riboside (VIII) was allowed to react with triphenylphosphine and carbon tetrachloride to give, after ammoniacal treatment, the 3'-chloro derivative (XI). Treatment of the compound XI with alkali gave a epoxide derivative (XVI). Hydrogenation of XI followed by acetylation gave 2', 5'-diacetyl derivative (XIII). When XIII was thiolated with phosphorus pentasulfide, 2', 5'-di-O-acetyl-thio-AICA-riboside (XIV) formed. Deacetylation of XIV with ammonia furnished XV, which did not show any significant antitumor activity.