Patent ID: 8507455

Claim:
An iRNA agent comprising at least one monomer having the structure shown in formula (I′) wherein: A and B are each independently for each occurrence O, N(R N ) or S; X is H, a protecting group, a phosphate group, a phosphodiester group, an activated phosphate group, an activated phosphite group, a phosphoramidite, a solid support, —P(Z′)(Z″)O-nucleoside, —P(Z′)(Z″)O-oligonucleotide, a lipid, a PEG, a steroid, a polymer, —P(Z′)(Z″)O-L 6 -Q′-L 7 -P(Z′″)(Z″″)O-oligonucleotide, a nucleotide, or an oligonucleotide; Y is H, a protecting group, a phosphate group, a phosphodiester group, an activated phosphate group, an activated phosphite group, a phosphoramidite, a solid support, —P(Z′)(Z″)O-nucleoside, —P(Z′)(Z″)O-oligonucleotide, a lipid, a PEG, a steroid, a lipophile, a polymer, —P(Z′)(Z″)O-L 6 -Q′-L 7 -OP(Z′″)(Z″″)O-oligonucleotide, a nucleotide, or an oligonucleotide; R is folate, a folate analog a folate mimic or a folate receptor binding ligand; L 6 and L 7 are each independently for each occurrence —(CH 2 ) n —, —C(R′)(R″)(CH 2 ) n —, —(CH 2 ) n C(R′)(R″)—, —(CH 2 CH 2 O) m CH 2 CH 2 —, or —(CH 2 CH 2 O) m CH 2 CH 2 NH—; Q′ is NH, O, S, CH 2 , C(O)O, C(O)NH, —NH—CH(R a )—C(O)—, —C(O)—CH(R a )—NH—, CO, R a is H or amino acid side chain; R′ and R″ are each independently H, CH 3 , OH, SH, NH 2 , NH(Alkyl) or N(diAlkyl); Z′, Z″, Z′″ and Z″″ are independently O or S; n represent independently for each occurrence 1-20; and m represent independently for each occurrence 0-50.