Preparation of 6-Azido-2-Chloropurine-2′-Deoxyriboside by Enzymatic Transglycosylation Reaction Catalyzed by Lactobacillus leichmannii Type II Nucleoside Deoxyribosyltransferase

6-azido-2-chloropurine-2'-deoxyriboside, a valuable precursor for the preparation of modified 2-chloropurine nucleosides substituted at the 6-position of the heterocyclic base, was obtained by enzymatic transglycosylation. 6-azido-2-chloropurine-2'-deoxyriboside can also be used as a photocross-linking agent to study the nucleic acids-proteins interactions. A type II nucleoside deoxyribosyltransferase from Lactobacillus leichmannii was used as a biocatalyst. The optimal conditions for the formation of 6-azido-2-chloropurine-2'-deoxyriboside using 7-methyl-2'-deoxyguanosine as a carbohydrate residue donor were determined.