Improved process for the preparation of nucleosidic phosphoramidites using a safer and cheaper activator

…, Z Guo, HM Pfundheller, A Converso

Index: Sanghvi, Yogesh S.; Guo, Zhiqiang; Pfundheller, Henrik M.; Converso, Antonella Organic Process Research and Development, 2000 , vol. 4, # 3 p. 175 - 181

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Citation Number: 56

Abstract

A new, simplified commercial process for the preparation of nucleosidic phosphoramidites, key raw materials for the automated solid-supported synthesis of oligonucleotide-based drugs, was developed. Phosphitylation of a variety of protected nucleosidic derivatives (1-4) with a small excess of 2-cyanoethyl-N, N, N', N'-tetraisopropyl phosphoramidite (5, bis- reagent) and pyridinium trifluoroacetate (Py⊙ TFA) as the activator in an appropriate ...