SYNTHESIS OF 8-AZA-1,3-DIDEAZA-2'-DEOXYADENOSINE AND 5,6-DISUBSTITUTED BENZOTRIAZOLE 2'-DEOXY-BETA-D-RIBOFURANOSIDES VIA NUCLEOBASE-ANION GLYCOSYLATION

The synthesis of 8‐aza‐1,3‐dideaza‐2′‐deoxyadenosine (3a) as well as of 4‐ and 5,6‐substituted benzotriazole 2′‐deoxy‐β‐D‐ribonucleosides is described (Schemes 1–3). Glycosylation of benzotriazole anions is stereoselective in all cases (exclusive β‐D‐anomer formation), but regioisomeric N1, N2, and N3‐(2′‐deoxyribofuranosides) are formed. The distribution of the regioisomers is controlled by the nucleobase substituents. Anomeric configuration as well as the position of glycosylation are determined by UV and NMR in combination with 1D‐NOE‐difference spectroscopy. The unprotonated forms of 4‐aminobenzotriazoic 2′‐deoxy‐β‐D‐ribofuranosides 3a–c exhibit strong fluorescence. Copyright © 1990 Verlag GmbH & Co. KGaA, Weinheim