摘要 |
Improved methods are described for solid-phase synthesis of morpholino oligomers, in which a protected morpholino ring nitrogen is deprotected between coupling steps using a heterocyclic amine salt in a trifluoroethanol-containing solvent, where the salt is a salt of a heterocyclic amine, having a pKa in the range of 1-4 in its protonated form, with an acid selected from a sulfonic acid, trifluoroacetic acid, and hydrochloric acid. Examples are 3-chloropyridinium methanesulfonate (CPM) and 4-cyanopyridinium trifluoroacetate (CYTFA).
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