Xylofuranosly-containing nucleoside phosphoramidites and polynucleotides

A compound having the formula I:

• 5
• wherein,
• R1 is OH, O—R3, wherein R3 is independently a moiety selected from a group consisting of alkyl, alkenyl, alkynyl, aryl, alkylaryl, carbocyclic aryl, heterocyclic aryl, amide and ester, C—R3, wherein R3 is independently a moiety selected from a group consisting of alkyl, alkenyl, alkynyl, aryl, alkylaryl, carbocyclic aryl, heterocyclic aryl, amide and ester, halo, NHR4 wherein R4 is independently a moiety selected from a group consisting of alkyl (C1-22), acyl (C1-22), substituted or unsubstituted aryl), or OCH2SCH3 (methylthiomethyl), ONHR5 where R5 is independently a moiety selected from a group consisting of H, aminoacyl group, peptidyl group, biotinyl group, cholesteryl group, lipoic acid residue, retinoic acid residue, folic acid residue, ascorbic acid residue, nicotinic acid residue, 6-aminopenicillanic acid residue, 7-aminocephalosporanic acid residue, alkyl, alkenyl, alkynyl, aryl, alkylaryl, carbocyclic aryl, heterocyclic aryl, amide or ester, ON=R6, where R6 is independently pyridoxal residue, pyridoxal-5-phosphate residue, 13-cis-retinal residue, 9-cis-retinal residue, alkyl, alkenyl , alkynyl, alkylaryl, carbocyclic alkylaryl, or heterocyclic alkylaryl;
• B is independently a nucleotide base or its analog or hydrogen;
• X is independently a phosphorus-containing group;
• and
• R2 is independently blocking group or a phosphorus-containing group.