METHOD OF SYNTHESIS OF 3'-PHOSPHATE,N,P-NONPROTECTED PHOSPHOTHIOATE ANALOGS OF OLIGODEOXYRIBONUCLEOTIDES Russian patent published in 1999 - IPC

FIELD: bioorganic chemistry, chemistry of nucleic acids. SUBSTANCE: invention relates to a method of synthesis of 3'-phosphate,N,P- -nonprotected phosphothioate analogs of oligodeoxyribonucleotides of the general formula (I) where B - a residue of thymine, cytosine, adenine or guanine; n = 1-20 that can be used as the parent compounds for synthesis of oligonucleotide reagents for biotechnological aims. Method involves the successive treatment of the parent protected oligonucleotides with iodine solution in an aqueous pyridine followed by treatment with an aqueous ammonia and acetic acid. The parent protected oligonucleotides are 5'-O-dimethoxytrityl,3'-p(S)SMe, N-acyl, P(S)SMe-protected phosphodithioate oligonucleotides of the general formula (III) where B' - a residue of thymine, N⁴-benzoylcytosine, N⁶-benzoyladenine, N²-isobutyrylguanine; DMTr is 4,4'-dimethoxytrityl; n = 1-20. EFFECT: increased yield of the end product, simplified process. 4 ex