A facile synthesis of the phosphoramidites of 2-N-methyl-2'-deoxy (or 2'- O-allyl)-ψ-isocytidine, 1,3-dimethyl-2'-deoxy-ψ-uridine and N1-methyl-2'- O-allyl-ψ-uridine as synthons suitable for oligonucleotide synthesis
An efficient and facile syntheses of 5'-O-(4,4'-dimethoxytrityl)-3'-[2- cyanoethyl bis(1-methylethyl)]phosphoramidites of 2-N-methyl-2'-deoxy-ψ- isocytidine (6), 2-N-methyl-2'-deoxy-α-ψ-isocytidine (13), 2-N-methyl-2'- O-allyl-ψ-isocytidine (11), 1,3-dime