Description
For many years, Glen Research has supplied methyl phosphoramidites in
addition to ß-cyanoethyl (CE) phosphoramidites for the few situations
where the more labile cyanoethyl group is not an advantage. Some of our
customers, probably remembering that the methyl group was removed
specifically with thiophenol, have tried to use these monomers to
prepare the interesting, uncharged, and nuclease-resistant methyl
phosphotriester linkage. Unfortunately, this linkage is labile to
ammonium hydroxide and the regular phosphodiester linkage is formed
(along with a small amount of chain scission). We offer UltraMild
methyl phosphoramidites for this application. Oligos produced from
these monomers can be deprotected with potassium carbonate in methanol
to produce methyl phosphotriester linkages.
Product Specifications
F.W.:
343.23 (Methyl triester)| FW: 329.21 (Phosphodiester)
Since these linkages are
diastereomeric and uncharged, the oligos may be hard to handle.
Consequently, it is likely that chimeras will be produced using these
monomers along with the regular UltraMild CE phosphoramidites. If many
dG residues are included in the oligonucleotide, we recommend the use
of phenoxyacetic anhydride (Pac2O) in Cap A. This modification removes
the possibility of exchange of the isopropyl-phenoxyacetate (iPr-Pac)
protecting group on the dG with acetate from the acetic anhydride
capping mix.
Usage
- Coupling:
No changes needed from standard method recommended by synthesizer
manufacturer. To avoid any exchange of the iPr-Pac group on the dG with
acetyl, use UltraMild Cap Mix A (40-4210-xx/40-4212-xx).
- Deprotection:
UltraMILD deprotection: 0.05M Potassium Carbonate in Methanol, 4 hours
at Room Temperature to leave the methyl phosphotriester intact.
Safety Data Sheet
Procedure for UltraMild Deprotection of Oligonucleotides
Glen Report 14.16: Product Update - How Are Methyl Triester Linkages Prepared?
| Diluent |
Anhydrous Acetonitrile |
| Storage |
Refrigerated storage, maximum of 2-8°C, dry |
| Stability |
2-3 days |
If you cannot find the answer to your problem then please contact us or telephone +44 (0)1954 210 200