Synthesis of 3-Glycofuranosyl-5-aminopyrazolopyrimidine-7-thiones: Thioguanosine-Type C-Nucleosides

Article abstract of DOI:10.1021/jo00177a028

The first C-nucleosides of the thioguanosine type are the 3-β-D-ribofuranosyl, 3-β-D-arabinofuranosyl, and 3-(2-deoxy-β-D-erythro-pentofuranosyl)derivatives of 5-aminopyrazolo<4,3-d>pyrimidine-7-thione.Synthesis of these products employed C6H5CH2SC(Cl)=NCOC6H5 as a new reagent for ring closure of the 3-glycofuranosyl-4-aminopyrazole-5-carbothiamide precursors.The new ring closure requires fewer steps and minimizes side reactions encountered in previous guanosine ring closure.The amino thioamide precursors are prepared from pyrazole C-nucleosides available as in previous formycin syntheses.