摘要 |
The compound S-(2,4-dichlorobenzyl)- beta -cyanoethyl phosphorothioate diester is disclosed as useful in the synthesis of phosphorothioate oligonucleotides. In certain embodiments of the invention, this reagent is used to prepare 3'-S-(alkaryl) phosphorothioates. The beta -cyanoethyl blocking group can be removed and the resulting diester reacted with a nucleotide having a free 5'-hydroxyl group to yield compounds of the structure: <IMAGE> where X is H, a first blocking group, a nucleoside, a nucleotide or an oligonucleotide; Y is H, a second blocking group, a nucleotide or an oligonucleotide; R is an alkaryl or aryl group; n is an integer greater than 0; and Bx is a heterocyclic base. Deblocking of the S-alkaryl or S-aryl moiety yields a phosphorothioate oligonucleotide.
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