Synthesis of 2‐(β‐D‐ribofuranosyl)[1,3,5]triazines

The synthesis of the first [1,3,5]triazine carbon linked nucleosides are reported. 4‐Amino‐6‐(β‐D‐ribofuranosyl)[1,3,5]triazin‐2(1 H )‐one ( 8 ), an analog of 5‐azacytidine and pseudoisocytidine was prepared. 2,5‐Anhydro‐D‐allonamidine hydrochloride ( 3 ) was condensed with dimethyl cyanoiminodithiocarbonate ( 4 ) to give 4‐methylthio‐6‐(β‐D‐ribofuranosyl)[1,3,5]triazin‐2‐amine ( 5 ). Compound 5 was reacted with m ‐chloroperbenzoic acid to give 4‐methylsulfinyl‐6‐(β‐D‐ribofuranosyl)[1,3,5]triazin‐2‐amine ( 6 ). Displacement of the methyl sulfinyl with the appropriate nucleophile gave 6‐(β‐D‐ribofuranosyl)[1,3,5]triazine‐2,4‐diamine ( 7 ), 4‐amino‐6‐(β‐D‐ribofuranosyl)[1,3,5]triazin‐2(1 H )‐one ( 8 ), and 4‐amino‐6‐(β‐D‐ribofuranosyl)[1,3,5]triazine‐2(1 H )‐thione ( 9 ). Dethiation of compound 5 with Raney nickel gave 4‐(β‐D‐ribofuranosyl)[1,3,5]triazin‐2‐amine ( 10 ). The crystal structure of 7 was determined by single crystal X‐ray.