Patent ID: 8309707

Claim:
A phosphoramidite having formula (1), where, Y is an oxygen atom or a sulfur atom; W is selected from the group consisting of an oxygen diradical, a N—H diradical and a fluorine radical, and R 4 is selected so that, if W is an oxygen diradical, then R 4 is tert butyl dimethyl silyl (TBDMS) or triisopropylsilyloxymethylene (TOM); if W is a N—H diradical, then R 4 is of the form R 5 x where x is selected from the group consisting of fluorenylmethyloxycarbonyl (Fmoc), trifluoroacetyl, acetyl, alkanoyl, and aroyl; and if W is a fluorine radical, then R 4 is not present; B is selected from the group of nucleoside base radicals consisting of -9-(N 6 -benzoyladeninyl)-, 9-(N 6 -acetyladeninyl)-, 9-(N 6 -tert butyl phenoxyacetyladeninyl)-, 9-(N 6 -phenoxyacetyladeninyl)-, 9-(N 6 -isopropyl phenoxyacetyladeninyl)-, 1-(N 4 -benzoylcytosinyl)-, 1-(N 4 -acetylcytosinyl)-, 1-(N 4 —(N,N-dimethylformamidinyl)cytosinyl)-, 1-(N 4 -phenoxyacetylcytosinyl)-, 1-(N 4 -tertbutylphenoxyacetylcytosinyl)-, 1-(N 4 -isopropyl phenoxyacetylcytosinyl)-, 9-(N 2 -isobutyrylguaninyl)-, 9-(N 2 -tertbutylphenoxyacetylguaninyl)-, 9-(N 2 -isopropylphenoxyacetylguaninyl)-N 4 -phenoxyacetylcytosinyl)-, 1-(N 4 -tertbutylphenoxyacetylcytosinyl)-, 1-(N 4 -isopropyl phenoxyacetylcytosinyl)-, and 1-uracilyl-; or, B is a modified nucleoside base radical selected from the group consisting of 1-(N 4 -benzoyl-5-methylcytosinyl)-,1-(N 4 —(N,N-dimethylformamidinyl)-5-methylcytosinyl)-,1-(N 4 -acetyl-5-methylcytosinyl)-,1-(5-methyl-uracilyl)-, -(5-fluoro-uracilyl)-,1-(N 4 -benzoyl-5-fluorocytosinyl)-, 9-(N 6 -benzoyl-7-deazaadeninyl)-, 9-(N 6 —(N,N-dimethylformamidinyl)-7-deazaadeninyl)-, 9-(N 2 -isobutyryl-7-deazaguaninyl)-, and 9-(N 2 —(N,N dimethylformamidinyl)-7-deazaguaninyl)-; Z is a protecting group selected from the group consisting of dimethoxytriphenylmethyl (DMT), monomethoxytriphenylmethyl (MMT) and trimethoxytriphenylmethyl (TMT); R 1 is an alkyl or aryl radical; R 2 is an alkyl or aryl radical; and, R 3 is a cyanoethyl radical, alkyl radical or aryl radical.