Patent ID: 8680262

Claim:
A method for purifying a protected oligonucleotide comprising: a1) providing a solution of said protected oligonucleotide in at least one solvent (A) having a boiling point below the boiling point of a solvent (B); a2) heating said solution of said protected oligonucleotide in at least one solvent (A) at a temperature of at least 30° C. and below the boiling point of said at least one solvent (A); a3) adding solvent (B) to said solution until precipitation of a material is visible, said solvent (B) being an alcohol having 1 to 6 carbon atoms or a diol having 2 to 6 carbon atoms; a4) allowing said solution to cool down under stirring until formation of a supernatant and a residue; and a5) removing said supernatant; or b1) providing solvent (B), said solvent (B) being an alcohol having 1 to 6 carbon atoms or a diol having 2 to 6 carbon atoms; b2) heating said solvent (B) at a temperature above 30° C. and below the boiling point of said solvent (B); b3) adding a solution of a protected oligonucleotide in at least one solvent (A) to said solvent (B) until precipitation of a material is visible in the solution; b4) allowing said solution to cool down under stirring until formation of a supernatant and a residue; and b5) removing said supernatant.