Nucleic Acid Component Analogues: Synthesis of 2′-Deoxynucleosides from 5-Substituted-4-hydroxy-6(1H)-pyrimidinones.

Condensation of the silylated pyrimidines 5a-c with methyl 2-deoxy-3,5-di-O-toluoyl-D-pentofuranoside 6, using trimethylsilyltriflate as catalyst gave anomeric mixtures of 2'-deoxynucleosides 7a-c, the pure alpha- and beta-anomers were separated and deprotected with sodium methoxide in methanol to give 1-(2'-deoxy-alpha-D-pentafuranosyl)-4-hydroxy-5-substituted-6(1H)-pyrimidinones 10a,b and 13a and their corresponding beta-anomers 11a,b and 13b.