Published on Sept. 29, 1988 in Tetrahedron Letters volume Volume 30, Issue 1, 1989.

DOI: 10.1016/S0040-4039(01)80326-9

Abstract:

The use of phenoxyacetyl group for the protection of the exocyclic amino function of purine bases and acetyl group for cytosine in oligonucleotide synthesis by the cyanoethylphosphoramidite approach is described. A side reaction - i.e. partial replacement of phenoxyacetyl group of protected guanines by acetyl group - was observed during the capping step. It can be avoided by the use of phenoxyacetic anhydride in place of acetic anhydride.