Dinucleoside methylphosphonates can easily be prepared starting from properly protected d-nucleosides and the bifunctional phosphorylating reagent methyl-O,O-bis(1-benzotriazolyl)phosphate. Separation of the diastereoisomers of 5'-DMTR-d-Ap(Me)T-3'-lev affords optically pure dinucleoside methylphosphonates which, after removal of the 3'-levulinoyl group, have been used for the synthesis of the two optically pure diastereoisomers of the hexamer d-CpGpAp(Me)TpCpG. Further, a one-pot procedure for the preparation of uridine-3',5'-cyclic methylphosphonate will be described. We also found that 3',5'-methylphosphonate linkages in RNA are not stable towards mild acid treatment.
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http://dx.doi.org/10.1093/nar/14.5.2171 | DOI Listing |
J Biomol Struct Dyn
June 1999
Institute of Organic Chemistry, Johann Wolfgang Goethe-Universität, Frankfurt am Main, Germany.
Methylphosphonate oligodeoxynucleotides (MPO's) with isomerically pure Rp-configurated methylphosphonates (MP's) were synthesized by block coupling of ApT and TpA dinucleoside methylphosphonates (DMP's, p indicating MP-linkage). Oligonucleotide duplexes (20 mers) with these Rp-MP's showed almost the same melting temperatures (Tm) as those with phosphorodiester bonds. Further a dependence of the duplex stability from the nucleosides (bases) adjacent to the MP moiety was observed.
View Article and Find Full Text PDFJ Biomol Struct Dyn
August 1997
Institute of Bioorganic Chemistry, Polish Academy of Sciences, Poznan, Poland.
Some conformational feature of dithymidine nucleotides containing natural 3'-->5' phosphodiester, methylphosphonate, or 5'-methylenephosphonate internucleotidic linkages were probed in solution and in solid phase using FTIR spectroscopy. A high similarity of the IR spectra in the region of 1800-1250 cm-1 indicates that all the investigated compounds have similar glycosidic torsion angels and the preferred conformation of the deoxyribose rings. However, small but significant differences between the Rp and Sp diastereomers of methylphosphonate analogue 5 may suggest that the association or the hydration mode of these compounds may vary.
View Article and Find Full Text PDFNucleic Acids Res
August 1993
Department of Organic Chemistry, Arrhenius Laboratory, Stockholm University, Sweden.
The molecular structure of one diastereomer of the dinucleoside methylphosphonate Tp(Me)sT (1) has been determined by X-ray diffraction methods. The crystal asymmetric unit contains one molecule of 1 and one methanol in an orthorhombic unit cell of dimensions a = 13.241(4), b = 13.
View Article and Find Full Text PDFJ Biomol Struct Dyn
December 1991
Department of Crystallography and Biophysics, University of Madras, India.
Molecular mechanics studies are performed on single stranded as well as base paired forms of dinucleoside methylphosphonates comprising different base sequences for both the S- and R-isomers of methylphosphonate (MP). S-MP produces noticeable distortions in the geometry, locally at the phosphate center, and this enables the stereochemical feasibility of compact g- g- phosphodiester. Besides, it tends to perturb the conformations around the P-O3' and glycosyl bonds, causing minor variations in stacking interactions.
View Article and Find Full Text PDFNucleic Acids Symp Ser
November 1992
Institut für Organische Chemie, Universität Frankfurt, FRG.
Oligonucleotides bearing phosphorothioate linkages of the HIV tatIII splice acceptor site were synthesized by automated solid phase synthesis. Especially 5'- and 3'-end capped thioates of the sequence 5'-ACACCCAATTCTGAAAATGG-3' show microM inhibition of HIV replication. ODN-methylphosphonates of defined stereochemistry were obtained with suitably modified proline phosphonamidite derivatives as monomeric building blocks.
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