239 results about "Phosphoramidite" patented technology

Novel technology for RNA synthesis in the reverse direction, involving a new class of products, 3′-DMT-5’-CE ribonucleoside phosphoramidites and 3′-DMT-5’-succinyl ribonucleoside solid supports, with per step coupling efficiency surpassing 99% in the RNA synthesis. This leads to high purity RNA. Examples of a large number of 20-21 mers and a few examples of long chain oligonucleotides are demonstrated. The data indicates dramatic improvement in coupling efficiency per step during oligonucleotide synthesis using the reverse RNA monomers (5′→′ direction) as compared to 3′-CE ribonucleoside phosphoramidites used in the conventional method of RNA synthesis (3′→5′ direction). The new process requires shorter coupling cycle time, approx. 4 minutes as compared to approx. 10 minutes using conventional RNA synthesis method (3′→5′ direction). Furthermore, almost complete absence of M+1 impurities in the reverse RNA synthesis methodology were observed, even when the last phosphoramidite was a macromolecule. The process resulted in very high purity 3′-modified oligonucleotides after HPLC purification. As a result of high purity of synthesized RNA and clean introduction of various 3′-end modified RNA requiring long chain ligands, chromophores, fluorophores and quenchers, this method of RNA synthesis is expected to be a very useful method of choice for therapeutic grade RNA. The novel phosphoramidites of this invention, Rev-A-n-bz, Rev-C-n-bz, Rev-C-n-ac, Rev-G-n-ac and Rev-rU show HPLC purity greater than 98% and 31P NMR purity greater than 99.5%.

The present invention relates to compositions and methods for the preparation of modified nucleic acids. In particular, the present invention provides novel reagents and chemistries for the generation of linkers, modified phosphoramidites, and modified solid supports.