Solid phase synthesis phosphoramidite nucleotide

The total synthesis of yeast tRNA has been reviewed and the total synthesis of a 77-nucleotide RNA sequence with methionine acceptor activity has also been described.l A solid-phase procedure for RNA synthesis has been described wherein the nucleoside is attached covalently to the silica support, through the 5 -OH group via an ester bond, and then treated with excess bisdiisopropylaminomethoxyphosphine and isopropylammonium tetrazolide to form the immobilized nucleoside 3 -phosphoramidite in situ. Treatment with a base-protected 2 -0-tetrahydropyranylnucleoside and tetrazole followed by oxidation... 

Figure 8.3 Process of solid-phase phosphoramidite nucleotide synthesis. In the process, X = linker which is later incorporated into the polymer matrix DMTr = dimethoxy trityl protecting group which is removed by treatment with add to hberate the hydroxyl gronp for snbseqnent phosphitylation reaction. B s = protected purine and pyrimidine bases. Phosphite is oxidized with iodine in the presence of esterification agent to phosphotriester before the chain extension or it is oxidized at the completion of chain extension as shown...

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