PROCESS FOR PURIFYING AND ISOLATING 2'-DEOXY-2',2'-DIFLUORONUCLEOSIDES

摘要

A process to purify and isolate a beta-anomer enriched nucleoside comprising : a) providing a mixture containing R" and a beta-anomer enriched nucleoside of formula (IB), wherein each X is independently selecte d from hydroxy protecting groups and R' is a nucleobase of formula (II), where W is an amino protecting groups; and R" is a nucleobase of formula (HI), where W' is an amino protecting group or hydrogen; in a high boiling solvent; b) diluting the mixture with an organic solvent from the group consisting of ethers, esters and nitriles; c) adding the diluted reaction mixture to aqueous acid; and d) holding the acid mixture so prepared at a temperature from 70 C to 100 C until the product of formula (IB), where W is now W', has precipitated.