Phosphoramidites
Phosphoramidites are the important class of intermediates for polynucleotide synthesis. Structurally phosphoramidites are the amides of trivalent phosphorus acids [2-Cyanoethoxy diisopropylamino phosphino group]. The phosphoramidites are sensitive towards water and oxygen. The main degradation involves oxidation, hydrolysis, and elimination of acrylonitrile and autocatalytic acrylonitrile-induced formation of cyanoethyl phosphonoamidates. Isolation and purification require special techniques and attention. Sapala has developed techniques for the synthesis of a wide range of nucleoside phosphoramidites with excellent purity.
- Orthogonally protected 3’-phosphoramidites of nucleosides
- 2’-Deoxy-5’-DMT-3’-phosphoramidites of nucleosides
- Orthogonally protected 5’-phosphoramidites
- Phosphoramidites of various sugar and base modified nucleosides
Phosphoramidites of nucleoside with a linker, such as an amino alkyl or an alkyl amide linker became popular in recent years. The following group of phosphoramidites can be made upon request.
- Biotin phosphoramidites
- Dye phosphoramidites
- Sugar phosphoramidites

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