2′ Modified RNA Phosphoramidites

Modifications at the 2′ position of the ribose ring are commonly used to help increase oligonucleotide stability and improve resistance to nuclease activity in vivo. Thermo Scientific 2'-modified RNA phosphoramidites ensure high level quality and reliability for all oligonucleotide synthesis needs. Phosphoramidites are manufactured to precise standards to reduce levels of critical impurities and supports a broad range of nucleic acid-based applications such as antisense, siRNA, gene design, and genome editing, including CRISPR-cas9 gRNA.

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RNA oligonucleotides synthesized using 2′-MOE modifications phosphoramidites have shown to be more nuclease resistant, with lower toxicity, and slightly increased hybridization affinities, making them well suited for therapeutic in vivo applications, such as antisense (ASO), siRNA, and aptamers. 

  • Tightly controlled, critical impurities (eg. M-11)
  • Suitable for use with DNA and/or RNA phosphoramidites
  • Reliable, high quality oligonucleotide synthesis
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Cat. No. 27-1019 27-1020 27-1022 27-1021
Formula C50H58N7O9P C50H60N5O10P C47H60N7O10P C43H55N4O10P
Molecular weight 932.03 g/mol 922.0 g/mol 914.01 g/mol 819.0 g/mol
CAS # 251647-53-7 163759-94-2 251647-55-9 163878-63-5
Solution Clarity Free from undissolved particulate at 0.2M solution in ACN
HPLC purity*

 ≥ 99%

31P NMR purity* ≥ 99%
Shipping / Storage  condition Ambient / –20 °C
Water content ≤ 0.3% (by KF Method)
Total residual solvents ≤ 4.0%
Material Origin Non-animal source (no TSE/BSE risk)

* For more specification details, contact us.

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RNA oligonucleotides synthesized using 2′-Fluoro Bz A, iBu G, Ac C, and U phosphoramidites have increased thermal stability of RNA duplexes and nuclease resistance of single-stranded RNA. These phosphoramidites can be incorporated into custom siRNA oligonucleotides for use in gene-targeting and suppression studies.

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  2′-Fluoro-Bz-A-CEP 2′-Fluoro-iBu-G-CEP TheraPure 2′-Fluoro-Ac-C-CEP TheraPure 2′-Fluoro-U-CEP TP 2'-Fluoro-Ac-G-CEP
Cat. No. 27-1601 27-1607 27-1604 27-1602 SY5410
C44H53FN7O8P C41H49N5FO8P C39H46FN4O8P C42H49FN7O8P
Molecular weight 875.92 g /mol 857.4 g/mol 789.8 g/mol 748.8 g/mol 829.87 g/mol
CAS # NA 144089-97-4 159414-99-0 146954-75-8 N/A
Appearance White to light yellow powder
HPLC purity* >98%
31P NMR purity* >98%
Residual Solvent N/A ≤ 3.0% total % by weight solvent 
Solution Clarity Free from undissolved particulate at 0.2M solution in ACN
Shipping / Storage condition Ambient / –20 °C
Water content ≤ 0.3%
Material Origin Non-animal source (no TSE/BSE risk)

* For more specification details, contact us.

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TheraPure (and standard) 2′-OMe phosphoramidites are presented in the table below.  For faster deprotection times, consider reviewing the PAC chemistries in combination with 2'-OMe U (no base protection) and Ac-rC.   

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  2′-OMe-Bz-A-CEP 2′-OMe-U-CEP 2′-OMe-iBu-G-CEP 2′-OMe-Ac-C-CEP
TheraPure Cat. No. 27-2042 27-2044 27-2046 27-2043
Cat. No. 27-1842 27-1825 27-1846 27-1823
Formula C48H54N7O8P C40H56N7O9P C45H56N7O9P C42H52N5O9P
Molecular weight 887.97 g/mol 760.8 g/mol 869.9 g/mol 801.86 g/mol
CAS # 110782-31-5 110764-79-9 150780-67-9 199593-09-4
Appearance Color intensity must not exceed Pantone #P1-4U or #P4-2U
HPLC purity (TheraPure) ≥ 98.0% | (>99%) *
M-11 Impurity ≤ 0.01%
31P NMR purity (TheraPure) ≥ 98.0% | (>99%) *
Shipping / Storage  condition Ambient / –20 °C
Water content  ≤ 0.2% (KF Method)
Material Origin Non-animal source (no TSE/BSE risk)

* For more specification details, contact us.

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Utilize PAC-A and iPrPAC-G with Ac-C and U to minimize deprotection times.  Acetylated amidites (such as Ac-G, SY5400) are ideal for shortening deprotection times for longmers. 

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  2′-OMe-PAC-A-CEP 2′-OMe-iPrPAC-G-CEP TheraPure 2'-OMe-Ac-G-CEP
Cat. No. 27-1822 27-1826 SY5400
Formula C49H56N7O9P C52H62N7O10P C43H52N7O9P
Molecular weight 918.0 g/mol 976.1 g/mol 841.9 g/mol
CAS # 128219-82-9 NA 909033-40-5
HPLC purity ≥ 98.0% ≥ 98.0% ≥ 99%
31P NMR purity ≥ 98.0% ≥ 98.0% ≥ 99%
Hazardous No
Shipping / Storage  condition Ambient / –20 °C
Material Origin Non-animal source (no TSE/BSE risk)
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Process and supply chain control

  • Processes are monitored from material procurement through final QC and product release, providing batch-to-batch reproducibility.
  • A controlled raw material supply chain and established vendor partnerships ensure consistency and security of supply
  • Purity of each 2'-modified phosphoramidite lot is assessed by HPLC and 31P NMR analyses
  • Rigorously controlled manufacturing processes minimize levels of reactive P(III) impurities which could be incorporated into the oligonucleotide and result in the accumulation of by-products

Custom services

  • Custom manufacturing services are available to assist in the development or scale-up of phosphoramidite compounds
  • Specialty phosphoramidites can be manufactured with base or sugar (2′, 3′ or 5′ positions) modifications

Flexible packaging

  • Common oligo synthesizer pack sizes are available for immediate delivery
  • Custom and bulk packaging are also available. Contact us to learn more.


Not finding what you are looking for? We also offer DNA phosphoramidites, RNA phosphoramidites, specialty phosphoramidites, dye-labeled phosphoramidites, linker and spacer phosphoramidites, and succinates and CPG support synthesis supports. Contact us to learn more.


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