[go: up one dir, main page]
More Web Proxy on the site http://driver.im/

WO1989009779A1 - Phosphoramidite reagent for chemical synthesis of modified dna - Google Patents

Phosphoramidite reagent for chemical synthesis of modified dna Download PDF

Info

Publication number
WO1989009779A1
WO1989009779A1 PCT/US1989/001395 US8901395W WO8909779A1 WO 1989009779 A1 WO1989009779 A1 WO 1989009779A1 US 8901395 W US8901395 W US 8901395W WO 8909779 A1 WO8909779 A1 WO 8909779A1
Authority
WO
WIPO (PCT)
Prior art keywords
azacytosine
dihydro
phosphoramidite
compound
residues
Prior art date
Application number
PCT/US1989/001395
Other languages
French (fr)
Inventor
Victor E. Marquez
Amanda J. Goddard
Original Assignee
United States Of America, Represented By The Secre
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by United States Of America, Represented By The Secre filed Critical United States Of America, Represented By The Secre
Priority to JP1504376A priority Critical patent/JPH0692435B2/en
Publication of WO1989009779A1 publication Critical patent/WO1989009779A1/en

Links

Classifications

    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07H—SUGARS; DERIVATIVES THEREOF; NUCLEOSIDES; NUCLEOTIDES; NUCLEIC ACIDS
    • C07H19/00—Compounds containing a hetero ring sharing one ring hetero atom with a saccharide radical; Nucleosides; Mononucleotides; Anhydro-derivatives thereof
    • C07H19/02—Compounds containing a hetero ring sharing one ring hetero atom with a saccharide radical; Nucleosides; Mononucleotides; Anhydro-derivatives thereof sharing nitrogen
    • C07H19/04—Heterocyclic radicals containing only nitrogen atoms as ring hetero atom
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07H—SUGARS; DERIVATIVES THEREOF; NUCLEOSIDES; NUCLEOTIDES; NUCLEIC ACIDS
    • C07H19/00—Compounds containing a hetero ring sharing one ring hetero atom with a saccharide radical; Nucleosides; Mononucleotides; Anhydro-derivatives thereof
    • C07H19/02—Compounds containing a hetero ring sharing one ring hetero atom with a saccharide radical; Nucleosides; Mononucleotides; Anhydro-derivatives thereof sharing nitrogen
    • C07H19/04—Heterocyclic radicals containing only nitrogen atoms as ring hetero atom
    • C07H19/12—Triazine radicals
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07H—SUGARS; DERIVATIVES THEREOF; NUCLEOSIDES; NUCLEOTIDES; NUCLEIC ACIDS
    • C07H21/00—Compounds containing two or more mononucleotide units having separate phosphate or polyphosphate groups linked by saccharide radicals of nucleoside groups, e.g. nucleic acids

Definitions

  • the present invention relates to the synthesis of DNA containing modified cytosine bases, namely 5-6- dihydro-5-azacytosine and 5-azacytosine, and more specifically to a reagent for use in the chemical synthesis of modified DNA which allows the incorporation of said bases at specific sites of a sequence.
  • the ability to synthesize polynucleotide fragments having a desired necleotide sequence is a useful tool in both research and applied molecular biology.
  • Short synthetic polynucleotides, or oligonucleotides are useful as adaptors or linkers in joining longer DNA segments, and as hybridization probes and DNA synthesis primers.
  • Longer polynucleotides can be constructed from shorter segments having overlapping cohesive ends and used as structural genes, regulatory regions such as promoters, terminators, operators, and the like. It is thus of great interest to provide convenient automatic techniques for producing synthetic DNA fragments with high yields in a relatively short time.
  • nucleotide sequences such as DNA
  • DNA DNA
  • One of these reactions is the postreplicative modification of newly synthesized DNA by the selective methylation of certain cytosine residues which is performed enzymatically by a specific DNA methylase.
  • An understanding of the factors governing the formation of specific methylation patterns in eucaryotic DNA is very important if we are to understand the mechanisms of gene expression.
  • the synthesis is usually carried out either on a solid-phase substrate or in a solution.
  • Solid-phase synthesis relies on sequential addition of mononucleotides to a growing chain attached at one end to the substrate.
  • the solid phase permits easy separation of the reactants, but the method requires excess quantities of reactants and usually provides only small quantities (less than 1 mg) of the desired sequence.
  • Solution phase synthesis while it requires lesser amounts of the expensive reagents and can provide larger quantities of the product sequence, requires isolation and purification of the intermediate product after every addition. Virtually all automated polynucleotide systems rely on solid phase synthesis.
  • phosphite-triester method was greatly improved by the use of N,N-dialkylamino phosphites (amidites) which are more stable than the phosphor-chlorodite intermediates initially employed. While the phosphite-triester method is often favored because of the greater yield at each nucleotide addition, the phosphatetriester method is also suitable for automated polynucleotide synthesis.
  • the tight bed column is tightly packed with the solid-phase support and the reactants are introduced either in a single pass or by a recirculating stream.
  • Loose bed columns have been introduced to alleviate these problems partially. By slowly passing the reactant through the column, higher mass transfer rates are achieved and utilization of the expensive reactants is improved. Also, channelling is reduced, since the solid phase packing will shift to equalize the flow profile therethrough.
  • the support matrix is held in an enclosed vessel.
  • Reactants are introduced and the vessel contents agitated, typically by bubbling an inert gas through the liquid in the reactor. While such a system can provide very efficient utilization of the reactants by increasing the retention time in the reactor, relatively large volumes of the reactant and solvent are necessary to fill the reactor.
  • Urdea et al. in U.S. Patent No. 4,517,338, disclose a method and system for sequential modification of a linear polymeric molecule attached to a dispersed solid phase support by adding individual nucleotides in a predetermined order to a nucleotide chain.
  • the dispersed solid phase is retained within a reactor zone which is provided with access ports for the introduction and removal of reagents. Reagents are selectively delivered to the reactor zone through at least one of the access ports by a reagent manifold.
  • the protected 5,6-dihydro-5-azacytidine phosphoramidite, compound 9 has a very stable triazine ring, analogous to its parent nucleoside.
  • Figure 1 shows the fragmentation pattern for dimer 12 obtained by negative ion FAB mass spectroscopy, plotted as relative intensity vs. m/z.
  • Figure 2 shows autoradiography of synthetic oligonucleotides obtained after 5'-end labelling and polyacrylamide gel electrophoresis.
  • Lane 1 (CA)3, hexamer marker Lane 2, (AT)4, octamer marker Lane 3, TACGTCGCAG, parent decamer
  • Scheme 6 shows the phosphitylation of compound 8 in the presence of diisopropylamine in methylene chloride with chloro(diisopropylamino)methoxy phosphine to give 71% yield of compound 9 as a glassy substance after purification by silica gel column chromatography with 25% ethyl acetate in hexane.
  • the phosphoramidite of the present invention is used in a typical condensation reaction to synthesize DNA.
  • the phosphoramidite was mixed with 3'-O-acetyl thymidine, compound 10, as shown in Scheme 7, in acetonitrile in the presence of tetrazole as the condensing catalyst, according to the procedure of Pfleiderer and Schwarz (Tetrahedron Letters, 25; 5513, 1984).
  • Thin layer chromatography showed complete reaction after fifteen minutes, and the dimeric product was immediately oxidized in situ with a mixture of iodine, lutidine, THF, and water to give a quantative yield of the fully protected dimer phosphate, compound 11.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Health & Medical Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Biochemistry (AREA)
  • Molecular Biology (AREA)
  • Engineering & Computer Science (AREA)
  • Biotechnology (AREA)
  • General Health & Medical Sciences (AREA)
  • Genetics & Genomics (AREA)
  • Saccharide Compounds (AREA)
  • Measuring Or Testing Involving Enzymes Or Micro-Organisms (AREA)

Abstract

5,6-dihydro-5-azacytidine phosphoramidite is useful in the synthesis of oligonucleotides and DNA containing dihydro-5-aza- and 5-azacytosine bases. The modified oligonucleotides which contain 5-azacytosine residues at specific sites can be used to determine the mechanism of selective gene activation and the relationship existing between the presence of the triazine base and inhibition of DNA methylation.

Description

PHOSPHORAMIDITE REAGENT FOR CHEMICAL SYNTHESIS
OF MODIFIED DNA
FIELD OF THE INVENTION The present invention relates to the synthesis of DNA containing modified cytosine bases, namely 5-6- dihydro-5-azacytosine and 5-azacytosine, and more specifically to a reagent for use in the chemical synthesis of modified DNA which allows the incorporation of said bases at specific sites of a sequence. BACKGROUND OF THE INVENTION
The ability to synthesize polynucleotide fragments having a desired necleotide sequence is a useful tool in both research and applied molecular biology. Short synthetic polynucleotides, or oligonucleotides, are useful as adaptors or linkers in joining longer DNA segments, and as hybridization probes and DNA synthesis primers. Longer polynucleotides can be constructed from shorter segments having overlapping cohesive ends and used as structural genes, regulatory regions such as promoters, terminators, operators, and the like. It is thus of great interest to provide convenient automatic techniques for producing synthetic DNA fragments with high yields in a relatively short time.
As the understanding of the function, structure, and chemical makeup of nucleotide sequences, such as DNA, has evolved, so too has the awareness of the practicalities and feasibilities of genetic engineering. These engineering efforts, however, require a complete understanding of the chemical and biological reactions in cells. One of these reactions is the postreplicative modification of newly synthesized DNA by the selective methylation of certain cytosine residues which is performed enzymatically by a specific DNA methylase. An understanding of the factors governing the formation of specific methylation patterns in eucaryotic DNA is very important if we are to understand the mechanisms of gene expression.
Basic to such genetic engineering efforts is the synthesis of desired nucleotide chains from single mononucleotides. In this regard, electromechanical apparatus has been developed for synthesizing desired oligomicleotide sequences via the sequential linking of desired bases to a starting nucleotide.
At present, a variety of approaches for polynucleotide synthesis are available. These approaches can be characterized based on several criteria. First, the synthesis is usually carried out either on a solid-phase substrate or in a solution. Solid-phase synthesis relies on sequential addition of mononucleotides to a growing chain attached at one end to the substrate. The solid phase permits easy separation of the reactants, but the method requires excess quantities of reactants and usually provides only small quantities (less than 1 mg) of the desired sequence. Solution phase synthesis, while it requires lesser amounts of the expensive reagents and can provide larger quantities of the product sequence, requires isolation and purification of the intermediate product after every addition. Virtually all automated polynucleotide systems rely on solid phase synthesis.
There are presently two synthesis chemistries in widespread used for automated polynucleotide synthesis. The triester method, as described by Catlin and Cramer J . Org. Chem. 38: 245-250 (1973) and Itakura et al., Can. J. Chem. 51: 3649-3651 (1973) which relies on the addition of suitable blocked phosphate-triester intermediates which are generally inexpensive and stable. The phosphite-triester method, as described by Letsinger and Lunsford in J . Am. Chem. Soc. 98:3655 (1975) is somewhat more complex, but generally provides higher yields than the phosphate triester method. The utility of the phosphite-triester method was greatly improved by the use of N,N-dialkylamino phosphites (amidites) which are more stable than the phosphor-chlorodite intermediates initially employed. While the phosphite-triester method is often favored because of the greater yield at each nucleotide addition, the phosphatetriester method is also suitable for automated polynucleotide synthesis.
Among the reactor systems that can be used in synthesizing polynucleotides are solid-phase reactor systems which use either a tight bed column, a loose bed column, or a batch reactor. The tight bed column is tightly packed with the solid-phase support and the reactants are introduced either in a single pass or by a recirculating stream.
Loose bed columns have been introduced to alleviate these problems partially. By slowly passing the reactant through the column, higher mass transfer rates are achieved and utilization of the expensive reactants is improved. Also, channelling is reduced, since the solid phase packing will shift to equalize the flow profile therethrough.
In a batch reactor, the support matrix is held in an enclosed vessel. Reactants are introduced and the vessel contents agitated, typically by bubbling an inert gas through the liquid in the reactor. While such a system can provide very efficient utilization of the reactants by increasing the retention time in the reactor, relatively large volumes of the reactant and solvent are necessary to fill the reactor.
Urdea et al., in U.S. Patent No. 4,517,338, disclose a method and system for sequential modification of a linear polymeric molecule attached to a dispersed solid phase support by adding individual nucleotides in a predetermined order to a nucleotide chain. The dispersed solid phase is retained within a reactor zone which is provided with access ports for the introduction and removal of reagents. Reagents are selectively delivered to the reactor zone through at least one of the access ports by a reagent manifold.
Another apparatus for programmably synthesizing selected nucleotide sequences is described in Zelinka et al., U.S. Patent 4, 598,049.
The well known instability of the triazine ring of 5-azacytosine deoxyribonucleoside makes it unsuitable for use as a building block in the aforementioned automated DNA syntheses. Despite this drawback, interest in the synthesis of single and double stranded DNA fragments containing 5-azacytosine residues constitutes an important goal in the understanding of the mechanism of action of this drug. DNA incorporation of 5-azacytosine in living cells has been associated with inhibition of DNA methylase activity and consequent gene activation.
Because of the well established relationship that exists between the DNA incorporation of 5-azacytosine residues and gene activation, it would be useful to develop a methodology for the synthesis of oligonucleotide fragments which contain this unnatural base. These modified oligonucleotides, which would contain 5 ,6-dihydro-5-azacytosine and 5-azacytosine residues at specific sites, could serve as tools for elucidating the mechanism of selective gene activation and the relationship that exists between the presence of these triazine bases and inhibition of DNA methylation. A direct incorporation of the phosphoramidite of 2'-deoxy-5-azacytidine in DNA synthesis would result in failure, since the 2'-deoxy-5-aza-cytidine is extremely sensitive to acid or alkaline conditions.
SUMMARY OF THE INVENTION It is an object of the present invention to overcome deficiencies in the prior art, such as noted above.
It is a further object of the invention to provide a method for the synthesis of modified oligonucleotides containing either 5,6-dihyro-5-azacytosine or 5-azacytosine bases at specific sites of the sequence. it is another object of the present invention to provide a reagent for the automated synthesis of DNA to accomplish the incorporation of 5,6-dihydro-5-azacyto sine and 5-azacytosine bases.
It is also an object of the present invention to provide for a method of converting 5,6-dihydro-5-azacytosine to 5-azacytosine in an oligonucleotide structure.
It is yet a further object of the present invention to provide compounds for use in studying the mechanism of selective gene activation.
The use of a phosphoramidite of 2'-deoxydihydro-5-aza-cytidine in DNA synthesis results in the successful formation of the desired internucleotide linkage and permits the synthesis of modified DNA fragments, since it is totally compatible with all of the chemical steps used in DNA synthesis. At the conclusion of the synthesis, a very specific and easily performed oxidation generates the desired 5-aza-cytosine moiety. Since the hydrolytic instability of the triazine ring in 5-azacytosine nucleosides is very well documented, the use of a conventional phosphoramidite derivative of 5azacytosinedeoxyribose, compound 1, is impractical, as this would have resulted in the base-catalyzed cleavage of the triazine ring during the last deprotection step of the synthesis. The process of the present invention overcomes this problem by using a stable phosphoramidite precursor of 5-azacytosinedeoxyribose that permits regeneration of the desired 5-azacytosine base after the conclusion of the synthesis of the oligonucleotide.
The protected 5,6-dihydro-5-azacytidine phosphoramidite, compound 9, has a very stable triazine ring, analogous to its parent nucleoside.
The reactions according to the present invention are shown in the following reaction schemes:
Figure imgf000008_0001
el 2.2 eq. 1.3-dichloro-1,1,3.3-tetraisopropyldisuiloxane. pyridine. rt. 1 h, 97%. bl 8 eq. NaBH4, THF. rt. 1 h. 78%. cl i. 8 eq. isobutyryl chloxi de, pyridine/chlorofom , 0º, ii. MeOH. rt, 16 h, 84%. dl 1. 40 eq. glyoxal, pyridine, rt, thrice reduced to dryness. il. chloroform/water extraction. el 2 eq. isobutyryl chloride, pyridine, rt, 2 h, 81%. 11 1.2 eq. tetrabutylammonium fluoride, THF, rt.1 h, 60%. g1 1.2 eq. 4.4'-dimethoxytrityl chloride, pyridine. rt, 2 h. 50%. hl 2.2 eq. chloro- N,N-dibopropylamino methoxyphotphine, 4.2 eq. tetrazole, chloroform, rt, 15 min, 71%. Scheme 1 outlines the synthesis of 5-azacytidine phosphoramidite starting with 5-aza-cytosinedeoxyribose. Protection with 1,3-dichloro-1,1,3,3- tetraisopropyldisiloxane, followed by borohydride reduction of compound 2, gave the desired dihydro analog, compound 3, after purification by silica gel flash chromatography with 5% methanol in ethyl acetate. The 1H-NMR spectrum of compound 3 shows the newly generated C-6 methylene protons as an AB quartet centered at 4.40 ppm. The exocyclic amino group of compound 3 was then protected as the isobutyrylamide, compound 4, and purified by silica gel flash chromatography with 50% ethyl acetate in hexane. Complete protection of the triazine ring was accomplished with the introduction of the bis(isobutyryloxy)ethylene group, performed in the same manner as for 2'-deoxyguanosine. Thus, the intermediate diol, compound 5, isolated from the reaction of compound 4 with glyoxal, was reacted with isobutyryl chloride to give compound 6, which was purified by silica gel flash chromatography with 15% ethyl acetate in hexane. Removal of the tetraisopropyldisiloxane group in compound 6 with tetrabutylammonium fluoride gave compound 7, following a simple extraction in methylene chloride/water. Protection of the 5'-hydroxyl group was accomplished by the standard procedure using 4,4'-dimethoxytrityl chloride to yield compound 8 as a crystalline solid, mp 89-91°C (hexane). Finally, phosphitylation of compound 8 with chloro-N,N'-diisopropylaminomethoxyphosphite gave the desired phosphoramidite, compound 9, as a white solid, mp 67-69°C after purification by silica gel flash chromatography with 25% ethyl acetate in hexane.
The reactivity of the new phosphoramidite, compound 9, was initially tested under the standard conditions used for DNA synthesis in a typical tetrazolecatalyzed condensation reaction with 3'-O-acetylthymidine, as shown in Scheme 2. After 15 minutes, the reaction was complete, and was immediately oxidized in situ to give a quantitative yield of the fully protected dimer, compound 11. Removal of the dimethoxytrityl group with trichloroacetic acid and further treatment of the residue with concentrated ammonium hydroxide yielded the fully blocked dimer, compound 12.
Figure imgf000011_0001
al 1.5 eq phosonoramidne 9.5 eq tetrazole, MeCN, rt, 15 mm bl Iodine 3%: water. 2%; 2,6-luhdine. 2% THF 93%. rt. 10 min. cl trichloroacotic acid. 2% in dichloromethana rt, 10 min. d) conc. NH4OH. 50º 15 h e) i 250 eq bisltnmethylsilyl).tnfluoroacatamide, MeCN, reflux, 1 h, u. 50 % methanol in water, rt, 1 h
In order to test the new reagent, two decamers in which the cytosine base at positions 3 and 6 was replaced by the 5,6-dihydro-5-azacytosine moiety, were synthesized in an Applied Biosystems model 380A automated DNA synthesizer. Based on the trityl assay data, the stepwise yield was 98.5% and 98.4%, respectively, compared to 99.09% for the unmodified decamer.
The final conversion of the dihydrotriazine base to the aromatic triazine was successfully accompushed by the use of bis(trimethylsilyl)trifluoro-acetamide (BSTFA) and trimethylsilyl chloride as silylating reagents, and trimethylsilyl peroxide as an oxidizing reagent. For the transformation the dimeric compound 12 was used as a model and the resulting dimer 13 was prepared in quantitative yield.
BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 shows the fragmentation pattern for dimer 12 obtained by negative ion FAB mass spectroscopy, plotted as relative intensity vs. m/z. Figure 2 shows autoradiography of synthetic oligonucleotides obtained after 5'-end labelling and polyacrylamide gel electrophoresis.
Lane 1: (CA)3, hexamer marker Lane 2, (AT)4, octamer marker Lane 3, TACGTCGCAG, parent decamer
Lane 4, TAXGTCGCAG, 3-modified decamer Lane 5, TACGTXGCAG, 6-modified decamer X = 5,6-dihydro-5-azacytidine. DETAILED DESCRIPTION OF THE INVENTION The detailed reaction schemes are shown as follows:
Figure imgf000013_0001
Figure imgf000014_0001
Figure imgf000015_0001
Figure imgf000016_0001
Figure imgf000017_0001
Figure imgf000018_0001
Figure imgf000019_0001
The synthesis of phosphoramidite according to the present invention started with 2'-deoxy-5-azacytidine, compound 1. As shown in Scheme 3, the 3' and 5' hydroxy groups were simultaneously protected with 1,3-dichloro-1,1,3,3-tetraisopropyldisiloxane using pyridine as solvent and base, according to the procedure of Markiewick et al. in Bull. Pol. Acad. Sci., 32: 433, 1984. This reaction proceeded in 97% yield, giving the desired compound 3 as a foam. In this and the following schemes, the tetraisopropyldisiloxane group is depicted as semicircle joining the 3' and 5' oxygen atoms of the nucleoside.
In the subsequent step, shown in Scheme 3, the double bond was reduced either catalytically with hydrogen over palladium on carbon, or more efficiently with sodium borohydride in tetrahydrofuran. After one hour of reaction, followed by treatment with methanol and water, workup and chromatography over silica gel with 5% methanol in ethyl acetate, the desired product, compound 4, was obtained in 78% yield as a foam.
Referring to Scheme 4, the exocyclic amino function was protected at this point in 84% yield by treatment of compound 3 with isobutyryl chloride in pyridine. After a conventional workup and silica gel chromatography with 50% hexane in ethyl acetate, compound 4 was obtained as a foam.
As shown in. Scheme 4, complete protection of the aglycon moiety was achieved by introducing the isobutyryloxyethylene group. Reaction of compound 4 with glyoxal, followed by treatment of the cyclized intermediate with isobutyrl chloride in anhydrous pyridine, gave compound 6 after purification by silica gel column chromatography with 15% ethyl acetate in hexane. Compound 6 was isolated as a foam in 61% yield. Referring to Scheme 5, compound 7 was prepared by removing the sugar tetraisopropyldisiloxane protective group with tetrabutylammonium fluoride at room tempera ture in THF. This compound was purified by simple extraction in methylene chloride after the reaction mixture was reduced to dryness and partitioned between water and methylene chloride to give compound 7 as a foam in 59% yield.
Selective protection of the 5'-hydroxy group, as required for DNA synthesis, was accomplished by the standard procedure using 4,4'-dimethoxytrityl chloride in dry pyridine to yield compound 8 is 50% yield as crystalline solid, mp 89-91°C.
Scheme 6 shows the phosphitylation of compound 8 in the presence of diisopropylamine in methylene chloride with chloro(diisopropylamino)methoxy phosphine to give 71% yield of compound 9 as a glassy substance after purification by silica gel column chromatography with 25% ethyl acetate in hexane.
The phosphoramidite of the present invention, compound 9, is used in a typical condensation reaction to synthesize DNA. The phosphoramidite was mixed with 3'-O-acetyl thymidine, compound 10, as shown in Scheme 7, in acetonitrile in the presence of tetrazole as the condensing catalyst, according to the procedure of Pfleiderer and Schwarz (Tetrahedron Letters, 25; 5513, 1984). Thin layer chromatography showed complete reaction after fifteen minutes, and the dimeric product was immediately oxidized in situ with a mixture of iodine, lutidine, THF, and water to give a quantative yield of the fully protected dimer phosphate, compound 11. Treatment of a solution of this dimer in dichloromethane with trichloroacetic acid removed the dimethoxytrityl group, and treatment of the residue with concentrated ammonium hydroxide at 55°C for fifteen hours yielded the fully deblocked target dimer, as shown in Scheme 8. An analytical sample of the deblocked dimer was obtained after reversed phase chromatography on J.T. Baker C-18 silical gel, 40 micrometers, 5% methanol in water, and as shown in Figure 1, the FAB/MS was consistent with the expected structure. Finally, the dihydro-5-azacytidine containing dimer, compound 12, was suspended in dry acetonitrile and treated with an excess of bis(trimethylsilyl)trifluoroacetamide, trimethylsilyl chloride, and trimethylsilylperoxide under reflux overnight, as shown in Scheme 9. Oxidation to the 5-azacytidine stage took place quantitatively as assessed by the dominance of the M-H peak in the mass spectrometer at m/z 531. The workup was very simple and involved evaporation of the volatile solvent and reagent and treatment of the residue with water to deblock the remaining oxygen and nitrogen to silicon linkages. Lyophilization of the aqueous solution yielded the desired dimer, compound 13.
In order to test the utility of the new reagent, two decamers, shown in Figure 2, lanes 4 and 5, in which the cytosine base at positions 3 and 6 was replaced by the 5,6-dihydro-5-azacytosine moiety, were synthesized in an Applied Biosysterns model 380A automated DNA synthesizer. Based on the trityl assay data, the stepwise yield was 98.5% and 98.4%, respectively, compared to 99.09% for the unmodified decamer (Figure 2, lane 3).
While the invention is described above in relation to certain specific embodiments, it will be understood that many variations are possible, and that alternative materials and reagents can be used without departing from the invention . In some cases such variations and substitutions may require some experimentation, but such will only involve routine testing. The foregoing description of the specific embodiments will so fully reveal the general nature of the invention that others can, by applying current knowledge, readily modify and/or adapt for various applications such specific embodiments without departing from the generic concept, and therefore such adaptations and modifications are intended to be comprehended within the meaning and range of equivalents of the disclosed embodiments. It is to be understood that the phraseology or terminology herein is for the purpose of description and not of limitation.

Claims

WHAT IS CLAIMED IS:
1. A 5,6-dihydro-5-azacytidine phosphoramidite suitable for use in the synthesis of modified DNA.
2. A method for the preparation of a 5,6-dihydro-5-azacytidine phosphoramidite comprising: protecting a 5-aza-cytosinedeoxyribose with a siloxane; reducing the protected 5-aza-cytosine-deoxyribose; protecting the exocyclic amino group and the triazine ring of the reduced, protected 5-aza-cytosinedeoxyribose; removing the siloxane group and protecting the hydroxyl group of the protected 5-aza-cytosine-deoxyribose; phosphitylating the resultant compound to produce a 5-azacytosine phosphoramidite.
3. The method of claim 2 wherein the siloxane is 1,3-dichloro-1,1,3,3-tetraisopropyldisiloxane.
4. The method of claim 2 wherein the exocyclic amino group is protected as an isobutyrylamide.
5. The method of claim 2 wherein the triazine ring is protected by introducing a bis(isobutyryloxy)ethylene group. 6. A condensation reaction for preparation of a dimer oligonucleotide comprising reacting 3'-O-acetyl thymidine with 5,
6-dihyro-5-azacytosine phosphoramidite.
7. A method for synthesizing DNA fragments comprising using a 5,6-dihydro-5-azacytidine phosphoramidite as a source of 5,6-dihydro-5 azacytosine and 5-azacytosine residues.
8. A method of oxidation for conversion of 5,6-dihydro-5-azacytosine residues to 5-azacytosine residues in an oligonucleotide.
9. The method of claim 8 wherein said 5,6-dihydro-5-azacytosine residues are produced by silylation using at least one silylating reagent selected from the group consisting of bis(trimethylsilyl) trifluoroacetamide and trimethylsilyl chloride, and which are oxidized by reaction with trimethylsilyl peroxide to produce said 5-azacytosine residues in an oligonucleotide.
PCT/US1989/001395 1988-04-06 1989-04-06 Phosphoramidite reagent for chemical synthesis of modified dna WO1989009779A1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP1504376A JPH0692435B2 (en) 1988-04-06 1989-04-06 Phosphoramidite reagent for chemical synthesis of modified DNA

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US178,153 1988-04-06
US07/178,153 US5324831A (en) 1988-04-06 1988-04-06 Phosphoramidite reagent for chemical synthesis of modified DNA

Publications (1)

Publication Number Publication Date
WO1989009779A1 true WO1989009779A1 (en) 1989-10-19

Family

ID=22651417

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/US1989/001395 WO1989009779A1 (en) 1988-04-06 1989-04-06 Phosphoramidite reagent for chemical synthesis of modified dna

Country Status (6)

Country Link
US (1) US5324831A (en)
JP (1) JPH0692435B2 (en)
AU (1) AU625295B2 (en)
CA (1) CA1330960C (en)
IL (1) IL89827A0 (en)
WO (1) WO1989009779A1 (en)

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0544824A4 (en) * 1990-07-27 1994-09-21 Isis Pharmaceuticals Inc Nuclease resistant, pyrimidine modified oligonucleotides that detect and modulate gene expression
WO1996006853A1 (en) * 1994-08-30 1996-03-07 Beckman Instruments, Inc. Activated nucleoside phosphoramidites and methods for the preparation and use thereof
WO1999062923A3 (en) * 1998-06-05 2001-05-31 Dynavax Tech Corp Immunostimulatory oligonucleotides with modified bases and methods of use thereof
WO2007041071A2 (en) 2005-09-29 2007-04-12 Supergen, Inc. Oligonucleotide analogues incorporating 5-aza-cytosine therein
US9381207B2 (en) 2011-08-30 2016-07-05 Astex Pharmaceuticals, Inc. Drug formulations
US10485764B2 (en) 2015-07-02 2019-11-26 Otsuka Pharmaceutical Co., Ltd. Lyophilized pharmaceutical compositions
US10519190B2 (en) 2017-08-03 2019-12-31 Otsuka Pharmaceutical Co., Ltd. Drug compound and purification methods thereof

Families Citing this family (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5585481A (en) * 1987-09-21 1996-12-17 Gen-Probe Incorporated Linking reagents for nucleotide probes
US6031091A (en) * 1987-09-21 2000-02-29 Gen-Probe Incorporated Non-nucleotide linking reagents for nucleotide probes
US6184347B1 (en) 1998-11-19 2001-02-06 Agilent Technologies Inc. Minimization of blooming in high-density arrays by using reactive wash reagents
WO2000056749A1 (en) 1999-03-24 2000-09-28 The Government Of The United States Of America, Represented By The Secretary, Department Of Health And Human Services N-acylphosphoramidites and their use in oligonucleotide synthesis
US20080261220A1 (en) * 2000-11-30 2008-10-23 Third Wave Technologies, Inc. Nucleic Acid Detection Assays
US20030072689A1 (en) * 2001-08-15 2003-04-17 Third Wave Technologies, Inc. Polymer synthesizer
US6932943B1 (en) 2001-01-26 2005-08-23 Third Wave Technologies Nucleic acid synthesizers
US7435390B2 (en) * 2001-01-26 2008-10-14 Third Wave Technologies, Inc. Nucleic acid synthesizers
AU2002353001A1 (en) * 2001-12-03 2003-06-17 The Government Of The United States Of America, Represented By The Secretary Of The Department Of He Thermolabile hydroxyl protecting groups and methods of use
WO2004028454A2 (en) * 2002-09-24 2004-04-08 Koronis Pharmaceuticals, Incorporated 1, 3, 5-triazines for treatment of viral diseases
US20070207973A1 (en) * 2002-09-24 2007-09-06 Koronis Pharmaceuticals, Incorporated 1,3,5-Triazines for Treatment of Viral Diseases
WO2006065751A2 (en) * 2004-12-13 2006-06-22 Government Of The United States Of America, Represented By The Secretary, Department Of Health And Human Services Cpg oligonucleotide prodrugs, compositions thereof and associated therapeutic methods
US7829735B2 (en) * 2007-10-26 2010-11-09 Northwestern University Universal phosphoramidite for preparation of modified biomolecules and surfaces

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4058602A (en) * 1976-08-09 1977-11-15 The United States Of America As Represented By The Department Of Health, Education And Welfare Synthesis, structure, and antitumor activity of 5,6-dihydro-5-azacytidine
US4458066A (en) * 1980-02-29 1984-07-03 University Patents, Inc. Process for preparing polynucleotides

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3817982A (en) * 1971-12-29 1974-06-18 Syntex Inc 2{40 ,3{40 -unsaturated nucleosides and method of making
US4668777A (en) * 1981-03-27 1987-05-26 University Patents, Inc. Phosphoramidite nucleoside compounds
US4849513A (en) * 1983-12-20 1989-07-18 California Institute Of Technology Deoxyribonucleoside phosphoramidites in which an aliphatic amino group is attached to the sugar ring and their use for the preparation of oligonucleotides containing aliphatic amino groups
US4843066A (en) * 1986-11-27 1989-06-27 Nippon Zoki Pharmaceutical Co., Ltd. Novel adenosine derivatives and pharmaceutical composition containing them as an active ingredient

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4058602A (en) * 1976-08-09 1977-11-15 The United States Of America As Represented By The Department Of Health, Education And Welfare Synthesis, structure, and antitumor activity of 5,6-dihydro-5-azacytidine
US4458066A (en) * 1980-02-29 1984-07-03 University Patents, Inc. Process for preparing polynucleotides

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
A. PISKALA, "Synthesis of 1-Glycosyl Derivatives of 5-Azauracil and 5-Azacytosine", Published 1964, by COLLECTION OF CZECHOSLOVAK CHEMICAL COMMUNICATIONS, (PRAGUE), pages 2060-2076. *

Cited By (17)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0544824A4 (en) * 1990-07-27 1994-09-21 Isis Pharmaceuticals Inc Nuclease resistant, pyrimidine modified oligonucleotides that detect and modulate gene expression
WO1996006853A1 (en) * 1994-08-30 1996-03-07 Beckman Instruments, Inc. Activated nucleoside phosphoramidites and methods for the preparation and use thereof
US5574146A (en) * 1994-08-30 1996-11-12 Beckman Instruments, Inc. Oligonucleotide synthesis with substituted aryl carboxylic acids as activators
WO1999062923A3 (en) * 1998-06-05 2001-05-31 Dynavax Tech Corp Immunostimulatory oligonucleotides with modified bases and methods of use thereof
US6562798B1 (en) 1998-06-05 2003-05-13 Dynavax Technologies Corp. Immunostimulatory oligonucleotides with modified bases and methods of use thereof
US9358248B2 (en) 2005-09-29 2016-06-07 Astex Pharmaceuticals, Inc. Oligonucleotide analogues incorporating 5-aza-cytosine therein
EP1943264A4 (en) * 2005-09-29 2013-08-14 Astex Pharmaceuticals Inc OLIGONUCLEOTIDE ANALOGUES INCORPORATING 5-AZACYTOSINE IN THESE
EP2944646A1 (en) * 2005-09-29 2015-11-18 Astex Pharmaceuticals, Inc. Oligonucleotide analogues incorporating 5-aza-cytosine therein
WO2007041071A2 (en) 2005-09-29 2007-04-12 Supergen, Inc. Oligonucleotide analogues incorporating 5-aza-cytosine therein
US9480698B2 (en) 2005-09-29 2016-11-01 Astex Pharmaceuticals, Inc. Oligonucleotide analogues incorporating 5-aza-cytosine therein
US10456415B2 (en) 2005-09-29 2019-10-29 Astex Pharmaceuticals, Inc. Oligonucleotide analogues incorporating 5-aza-cytosine therein
US10933079B2 (en) 2005-09-29 2021-03-02 Astex Pharmaceuticals, Inc. Oligonucleotide analogues incorporating 5-aza-cytosine therein
US9381207B2 (en) 2011-08-30 2016-07-05 Astex Pharmaceuticals, Inc. Drug formulations
US9913856B2 (en) 2011-08-30 2018-03-13 Astex Pharmaceuticals, Inc. Drug formulations
US10517886B2 (en) 2011-08-30 2019-12-31 Astex Pharmaceuticals, Inc. Drug formulations
US10485764B2 (en) 2015-07-02 2019-11-26 Otsuka Pharmaceutical Co., Ltd. Lyophilized pharmaceutical compositions
US10519190B2 (en) 2017-08-03 2019-12-31 Otsuka Pharmaceutical Co., Ltd. Drug compound and purification methods thereof

Also Published As

Publication number Publication date
JPH0692435B2 (en) 1994-11-16
JPH03502577A (en) 1991-06-13
CA1330960C (en) 1994-07-26
US5324831A (en) 1994-06-28
AU625295B2 (en) 1992-07-09
IL89827A0 (en) 1989-12-15
AU3368189A (en) 1989-11-03

Similar Documents

Publication Publication Date Title
US5324831A (en) Phosphoramidite reagent for chemical synthesis of modified DNA
US5359052A (en) Chalcophospholanes useful in the synthesis of oligonucleoside phosphorothioates, phosphorodithioates and related selenates
AU712779C (en) Method for solution phase synthesis of oligonucleotides
US6008400A (en) Orthoester reagents for use as protecting groups in oligonucleotide synthesis
US4659774A (en) Support for solid-phase oligonucleotide synthesis
US5512668A (en) Solid phase oligonucleotide synthesis using phospholane intermediates
EP0543906B1 (en) Hydroxyl-protecting groups orthogonally removable by reduction and their use in the chemical synthesis of oligonucleotides
EP0815114B1 (en) Nucleic acid synthesis using photoremovable protecting groups
AU737213B2 (en) Method for solution phase synthesis of oligonucleotides and peptides
WO2008037568A2 (en) Reversible terminators for efficient sequencing by synthesis
WO1995026972A1 (en) Modified oligonucleotides and intermediates useful in nucleic acid therapeutics
MXPA96004355A (en) Oligonucleotides and used modified intermediaries in nucleic acids therapeuti
EP0514513A1 (en) Method and means for oligonucleotide synthesis.
EP0979233A1 (en) Method for solution phase synthesis of oligonucleotides
US6001966A (en) Method for solution phase synthesis of oligonucleotides and peptides
Caruthers Synthesis of oligonucleotides and oligonucleotide analogues
EP0678096B1 (en) Synthesis of dimmer blocks and their use in assembling oligonucleotides
US6090934A (en) Universal support for the synthesis of oligonucleotides
Boryski A Novel approach to synthesis of 2′-deoxy-β-D-ribonucleosedes via transglycosylation of 6-oxopurine ribonucleosides
US6153742A (en) General process for the preparation of cyclic oligonucleotides
WO1989009780A1 (en) Site-specific tritium-labeled oligodeoxynucleotides
AU738032B2 (en) Method for solution phase synthesis of oligonucleotides
CN114014902A (en) Dimeric nucleotide and synthetic method thereof
AU5402901A (en) Method for solution phase synthesis of oligonucleotides
WO2006064039A1 (en) Synthesis of phosphitylated compounds using a quaternary heterocyclic activator

Legal Events

Date Code Title Description
AK Designated states

Kind code of ref document: A1

Designated state(s): AU JP