Fast, copper-free click chemistry: a convenient solid-phase approach to oligonucleotide conjugation

Singh, Ishwar; Vyle, Joseph S.; Heaney, Frances

doi:10.1039/b904185k

Cited by 56 publications

(40 citation statements)

References 29 publications

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“…benzyl azide (3) and cinnamyl azide (4) as well as those with potential for biomedical [35] or imaging [36] applications viz. glucose azide (5) as a mixture of α-and β-isomers, coumarin azide (6), biotin azide (7), cholesterol azide (8) and fluorescein azide (9).…”

Section: Resultsmentioning

confidence: 99%

“…[5] However, toxicity may remain an issue when oligonucleotide therapeutics are desired, and, in search of alternative bioconjugation methodologies, we and others have developed catalyst-free nitrone and nitrile oxide cycloadditions. [6][7][8][9][10][11] Additional, metal-free bioorthogonal conjugation strategies include Diels-Alder cycloadditions and photoinduceable cycloadditions of tetrazines or nitrile imines to alkenes. [12][13][14] More recent advances in this area include strain-promoted azide-alkyne cycloadditions (SPAAC).…”

Section: Introductionmentioning

confidence: 99%

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Efficient Synthesis of DNA Conjugates by Strain‐Promoted Azide–Cyclooctyne Cycloaddition in the Solid Phase

2011

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Efficient Synthesis of DNA Conjugates by Strain‐Promoted Azide–Cyclooctyne Cycloaddition in the Solid Phase

2011

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“…We have recently shown solid phase nitrile oxide click cycloaddition chemistry to be successful for the preparation of isoxazole modified DNA 19 and for generating 2¢-OMe ribonucleoside and ribonucleotide analogues by [3+2]-cycloaddition to 2¢-O-propargyl substrates. 23 In this paper we further demonstrate the utility of this reaction in the solution phase synthesis of sugar (C 3¢ -O) and nucleobase (N 3 -) tethered isoxazoles.…”

Section: Introductionmentioning

confidence: 99%

Nucleoside and nucleotide analogues by catalyst free Huisgen nitrile oxide–alkyne1,3-dipolar cycloaddition

2010

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An efficient, catalyst free, 1,3-dipolar cycloaddition strategy to conjugate nucleosides and nucleotides with isoxazoles under atmospheric conditions and in an aqueous environment is reported. The protocol involves chloramine-T as a practical reagent to induce in situ nitrile oxide formation and the alkyne partner is attached to the sugar residue or the nucleobase. The reactions are regiospecific, fast and high yielding.

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“…In one elegant example Pezacki et al circumvents this problem by employing nitrones as more reactive dipole partners. 14 We and others have recently discovered nitrile oxide click conjugation to alkenes 15,16 and to terminal alkynes [17][18][19] as a highly effective approach to chemical modification of oligonucleotides. Nitrile oxides are reactive 1,3-dipoles, and in the absence of an effective dipolarophile side reactions, including dimerisation leading furoxans, 1,2,4-oxadiazole-4-oxides or 1,4,2,5-dioxadiazines could be problematic.…”

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Solid phase strain promoted “click” modification of DNAvia[3+2]-nitrile oxide–cyclooctyne cycloadditions

Singh

Heaney

2011

Chem. Commun.

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Rapid, catalyst free, solid phase modification of DNA by strain promoted cyclooctyne-nitrile oxide click chemistry is reported; the reaction is characterised by mild conditions, occurring in an aqueous environment under atmospheric conditions at room temperature and is complete in 10 minutes.Chemically modified oligonucleotide-based drugs are promising therapeutic candidates, 1 however clinical applications are limited by poor cellular uptake. 2 The conjugation of oligonucleotides to molecules expected to facilitate their internalization, e.g. cell penetrating peptides or lipids, offers an attractive way to combat these shortcomings. 3 The Cu(I) catalysed azide and alkyne cycloaddition (CuAAC) reported by Meldal et al. 4 and Sharpless et al. 5 has been extensively used in synthetic chemistry and in chemical biology. 6,7 It is a high yielding and efficient reaction, however, for certain applications the requirement for the catalyst can be limiting. 6 The added metal can be cytotoxic 8 and can upset the metabolic balance of the systems under study, thus, a need exists to expand the field of metal free biocompatible chemistry. Approaches to-date include the photoinduceable cycloadditions of tetrazines 9b or nitrile imines to alkenes, 9a and the [3+2]-azide-cyclooctyne cycloaddition developed by Bertozzi et al. 10,11 and Boons et al. 12 The latter, exploiting the intrinsic ring strain of cyclooctynes 13 is a powerful reaction, yet it can require several hours to reach completion at room temperature. In one elegant example Pezacki et al. circumvents this problem by employing nitrones as more reactive dipole partners. 14 We and others have recently discovered nitrile oxide click conjugation to alkenes 15,16 and to terminal alkynes 17-19 as a highly effective approach to chemical modification of oligonucleotides. Nitrile oxides are reactive 1,3-dipoles, and in the absence of an effective dipolarophile side reactions, including dimerisation leading furoxans, 1,2,4-oxadiazole-4-oxides or 1,4,2,5-dioxadiazines could be problematic. 20 However, we anticipated high chemoselectivity for the desired cycloaddition with a very reactive strained cycloalkyne partner. Whilst there are numerous applications of cyclooctynes in the context of biological systems 21 to the best of our knowledge there are currently no reports describing their reaction with nitrile oxide dipoles, nor are there any reports on solid phase conjugation of oligonucleotides with ring strained alkynes. In the present communication we report the first preparation of a DNA ligated cyclooctyne and demonstrate its utility in strain promoted nitrile oxide click cycloadditions.The desired DNA-cyclooctyne was constructed by manual solid phase synthesis employing the phosphoramidite building block 4. Synthesis of this key intermediate, shown in Scheme 1, was achieved in three steps from the dibromobicycle 1, itself obtained by a known procedure 22 from commercially available cis-cycloheptene. Ring opening of 1 with 1,4-butanediol in the presence of silver perchlorate a...

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Fast, copper-free click chemistry: a convenient solid-phase approach to oligonucleotide conjugation

Abstract: Solid-phase oligonucleotide conjugation by nitrile oxide-alkyne click cycloaddition chemistry has been successfully demonstrated; the reaction, compatible with all nucleobases, requires no metal catalyst and proceeds under physiological conditions

Cited by 56 publications

References 29 publications

Efficient Synthesis of DNA Conjugates by Strain‐Promoted Azide–Cyclooctyne Cycloaddition in the Solid Phase

Efficient Synthesis of DNA Conjugates by Strain‐Promoted Azide–Cyclooctyne Cycloaddition in the Solid Phase

Nucleoside and nucleotide analogues by catalyst free Huisgen nitrile oxide–alkyne1,3-dipolar cycloaddition

Solid phase strain promoted “click” modification of DNAvia[3+2]-nitrile oxide–cyclooctyne cycloadditions

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