Biocatalytic separation of N-7/N-9 guanine nucleosides

Vorbrüggen coupling of trimethylsilylated 2-N-isobutanoylguanine with peracetylated pentofuranose derivatives generally gives inseparable N-7/N-9 glycosyl mixtures. We have shown that the two isomers can be separated biocatalytically by Novozyme-435-mediated selective deacetylation of the 5'-O-acetyl group of peracetylated N-9 guanine nucleosides.