反应详情

Concomitant hydrolysis of the nitrile function and the sugar protecting groups of compound 41 is carried out by the treatment with 0.1N NaOH solution to obtain 4-amino-3-(β-D-ribofuranosyl)-1,3-azaphospholine-5-carboxamide (compound 50). Compound 50 is ring closed with formamide or with triethyl orthoformate to obtain the inosine analog, compound S1 (X=O), which is also prepared by deamination of the adenosine analog, compound 44, with aqueous nitrous acid. Acetylation of the sugar hydroxyls with acetic anhydride/4-(dimethylamino)pyridine, followed by thiation with phosphorus pentasulfide and subsequent deacetylation provides the 6-thioinosine analog 3-(β-D-ribofuranosyl)-1,3-azaphospholo[4,5-d]pyrimidine-7(6H)-thione (compound 51, X=S).