Oligonucleosides synthesis

Bardella F, Eritja R, Pedroso E, Giralt E, Gel-phase 31P-NMR. A new analytical tool to evaluate solid phase oligonucleoside synthesis, Bioorg. Med. Chem. Lett., 3 2793-2796, 1993. 

Example 55 iV,iSr-diisopropyl-4-nitrophenylmethylphosphonoamidite has been applied in the synthesis of oligonucleoside methylphosphonates [89]. This stable crystalline compound prepared from methyldichlorophosphine, was employed in two ways in a procedure similar to that presented in the Examples 42 and 43. 

Jayaraman, K., McParland, K., Miller, P., and Tso, P.O.P. 1981. Non-ionic oligonucleoside methylphosphonates. 4. Selective inhibition of Escherichia coli protein synthesis and growth by non-ionic oligonucleotides complementary to the 3 end of 16S ribosomal-RNA. Proc. Natl. Acad. Sci. U.S.A. 78 1537-1541. 

Shaw has reviewed the various approaches to the synthesis of organophos-phate-oligonucleosides and has further commented on their chemical and biophysical properties along with their interactions with various enzymes such as DNA-polymerases, and compared them to other members of the family of phosphorus modified nucleic acids. She also reported the synthesis of P-tyrosinyl(P-0)-5 -P-nucleosidyl boranophosphates (23a,b), as antiviral and anticancer prodrug candidates. The P-boranophosphates were prepared by reacting a phosphoramidite intermediate obtained from protected tyrosine and the protected nucleoside in the presence of IH-tetrazole, followed by in situ borona-tion of the phosphite triester intermediate. The two diastereomers were then separated by reverse-phase HPLC. ... 

Deoxyribonucleotides, deoxyribonucleotide phosphorothioates, modified DNA, and analogs have wide applications in molecular biology, antisense applications, antigene therapy, etc. Three methods are available for the synthesis of oligonucleoside phosphorothioates phosphoramidite, H-phosphonate, and phospho-... 

Three papers have appeared on the solid support synthesis of oligonucleoside-peptide hybrids, using different solid supports and protection group strategy. ... 

In the area of modified intemucleosidic links, the use of the selenium-containing system 186 in the synthesis of oligonucleoside phosphorothioates has been prefmed to the earlier sulfur analogue since the P-Se bond is more labile in reaction with the 5 -OH group of the other... 

However, conversion of the dinucleoside //-phosphonate diester 10 to the phosphorothioate analogue 11 effected by a 0.02 M solution of 2 in 2% aqueous pyridine is relatively slow it reportedly takes 3 h for a complete reaction. While a solution of 2 in 2% aqueous acetonitrile containing triethylamine can completely transform 10 into 11 within 30 s, the use of this sulfurization mixture is incompatible with automated solid-phase oligonucleotide synthesis given the rapid formation of a yellow precipitate caused by triethylamine. In the absence of triethylamine, 10 is not sulfurized under these conditions. Nonetheless, 10 is completely converted to 11 within 20 min when a 0.02 M solution of 1 in 2% aqueous pyridine is used for the sulfurization reaction. Thus, 3i/-l,2-benzodithiol-3-one in aqueous pyridine is compatible with automated solid-phase synthesis of both DNA and RNA oligonucleoside phosphorodithioates or phosphorothioates from appropriate //-phosphonate derivatives. ... 

As a final addendum to the commentary in Section 3., it is worthwhile to discuss briefly two subjects of continual interest in the area of potential pharmaceutical applications of oligonucleoside phosphorothioates scale-up vis-a-vis solid-phase or solution synthesis and stereochemistry. ... 

Fig. 10. Stepwise synthesis of carboxymethyl-bridged oligonucleosides. (i) Sodium tert-butoxide in DMF, 100°C, 2 h, (ii) DCC in pyridine, 20 C, 24 h (lii) chain extension via 5 -end detritylation of IV followed by condensation with II, (iV) repetition of steps (i), and (ii)...

Fig. 13. Stepwise synthesis of acetamidate-bridged oligonucleosides B Thymine, 4-lV-MMTr-cytosine, 2-lV-MMTr-guanine, 6-TV-MMTr-adenine B unprotected bases cat HOBT, A -ethylmorpholine (i) NaH in DMSO at 0°C for 1-3 d (85%) (ii) DCC, HOBT, IV-ethylmorpholine (27) in DMF, O-20°C, 24h (50-70%) (iii) a. PPh3 at 0°C, 24 h, b. methanolic NHj 24 h (85%) (iv) ZnBr2 in nitromethane, 20°C, 24 h, 70%.

Fig 16. Stepwise synthesis of carbamate-bndged morpholino-type oligonucleosides. Cycle activation with bts-(p-nitrophenyl)carbonate, deblocking with 80% AcOH in methanol conjugation with p-nitrophenyl-O-CO-O-PEGlOOO deprotection with NH3/DMSO 30°C, 24 h. 

Coull, J M, Carlson, D. V., and Weith, H. L. (1987) Synthesis and characterization of a carbamate-lmked oligonucleoside Tetrahedron Lett. 28,745-748... 

The potential therapeutic applications of antisense ONs have rekindled the interest of researchers, including those at ISIS, in the development of better backbones for incorporation into ONs (Table 1). Comprehensive reviews of antisense ONs have been published, and here we present major developments from our group and others. Furthermore, this account is limited to the synthesis of oligonucleosides with a four-atom linker connecting the two pentofuranosyl moieties of a nucleoside dimer.I" In each section we describe a different type of backbone linkage. 

J. M. Coull, D.V. Carlson, and H.L. Weith, Synthesis and characterization of a carbamate-linked oligonucleoside. Tetrahedron Lett. 28 745 (1987). 

F. Debart, J-J. Vasseur, Y.S. Sanghvi, and P.D. Cook, Synthesis and incorporation of methyleneoxy(methylimino) (3 - 5 ) linked thymidine dimer into antisense oligonucleosides, Biomed. Chem. Lett. 2 in press (1992) Y.S. Sanghvi, J-J. Vasseur, F. Debart, and P.D. Cook, Novel strategies towards construction of non-ionic and achiral backbone in antisense oligonucleotides. Nucleic Acids Res. Synqwsium series No.27,133 (1992). 

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