Novel acyclic amide-conjugated nucleosides and their analogues.

An effective one-step synthesis of new amide-conjugated nucleosides and their analogues, in the presence of 4-(4,6-dimethoxy-1,3,5-triazin-2-yl)-4-methylmorpholinium chloride (DMT-MM) as the condensing agent, is presented. Substrate subunits carrying carboxylic group were obtained by acidic hydrolysis of Michael-type adducts of various 5-substituted uracil derivatives to methyl acrylate. Amine substrate was synthesized by reduction of 1-(2'-cyanoethyl)thymine with sodium borohydride in the presence of nickel (II) chloride as catalyst. Other applied amine substrates were 5'-amino-5'-deoxythymidine and 5-aminouracil.