2'-F-dU Phosphoramidite

2'-F-dU Phosphoramidite incorporates 2′‑fluoro‑2′‑deoxyuridine into synthetic oligonucleotides. The 2′‑fluoro modification dramatically increases the thermal stability of duplexes formed with complementary RNA (ΔTm ≈ +2–3°C per modification) compared to DNA or even 2′‑O‑methyl RNA, while also conferring exceptional resistance to nuclease degradation. 2'-F-dU Phosphoramidite is particularly valuable in siRNA design, where 2′‑F modifications in the sense strand can reduce off‑target effects and enhance metabolic stability without compromising RNAi activity. 2'-F-dU Phosphoramidite is also used in aptamer development, as the 2′‑F modification expands the chemical diversity of aptamer libraries and improves in vivo half‑life. The uridine base does not require an exocyclic amine protecting group (unlike C, A, or G), making 2'-F-dU Phosphoramidite simpler to deprotect — standard concentrated ammonia or AMA treatment removes the cyanoethyl group and cleaves the oligonucleotide from the support, with no additional steps for base deprotection. 2'-F-dU Phosphoramidite is fully compatible with standard DNA/RNA synthesizers, though coupling times may need to be extended (6–10 minutes) due to the electron‑withdrawing effect of the fluorine atom.

Product Parameters

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Synthetic Route

Under argon protection, 5 '-O-(4,4' -dimethoxytriphenylmethyl)-2 '-deoxy-2' -fluorouridine (3.00 g, 5.47 mmol) was dissolved in anhydrous dichloromethane (50 mL). N,N-diisopropylethylamine (0.55 mL, 3.18 mmol), 1H-tetrazole (0.45 g, 6.45 mmol), and bis(2-cyanethylamino)(2-cyanoethoxy)phosphine (1.92 g, 6.36 mmol) were added sequentially. The reaction mixture was stirred overnight at room temperature. Upon confirmation of completion by TLC, a 5% sodium bicarbonate aqueous solution (20 mL) was added to separate the layers; the organic layer was washed with saturated saline solution (20 mL). After drying with anhydrous sodium sulfate, the organic layer was concentrated under reduced pressure. The crude product was purified by silica gel column chromatography using a hexane/ethyl acetate mixture containing 3% triethylamine (from 75:25 to 30:70, v/v). The fraction containing the target product was collected and concentrated under reduced pressure, yielding (2R,3R,4R,5R)-2-(bis(4-methoxyphenyl)(phenyl)methoxy)methyl)-5-(2,4-dioxo-3,4-dihydropyrimidin-1(2H)-yl)-4-fluoro-4-hydroxytetrahydrofuran-3-yl(2-cyanethyl)disoisoprophosphamide (2.76 g, yield 67.3%).

Quality Assurance at Cosperpharm

Each batch undergoes:

● Gas chromatography (GC) – purity ≥97.0%

● Non‑aqueous titration – purity ≥97.0%

● Refractive index – confirmatory analysis

● ¹H NMR – structural verification

● Appearance – colorless to light yellow to light orange clear liquid

A comprehensive COA, MSDS (with full GHS information), and certificate of origin accompany every shipment.

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Need a reliable source of 2'-F-dU Phosphoramidite for your oligonucleotide synthesis program? Cosperpharm provides high‑purity monomer, full analytical documentation, and expert technical support from research to commercial scale. Contact us today.