Synthesis, Structure, and Conformational Analysis of Nucleoside Analogues Comprising Six‐Membered 1,3‐Oxathiane Sugar Rings

Abstract

We report on the synthesis, characterization, and conformational analysis of 1,3‐oxathiane nucleosides of both pyrimidine and purine nucleobases. The novel nucleoside analogues were prepared from readily available starting materials as α/β anomeric mixtures. The purine nucleosides were obtained as separable N7/N9 regioisomers. The structures were identified by extensive NMR analysis. The X‐ray structure of the N7‐β‐OMe‐purine nucleoside analogue 16 shows that the 1,3‐oxathiane sugar ring adopts a perfect chair conformation with both the hydroxymethyl and the nucleobase placed in equatorial positions.

Seven-Membered Ring Nucleoside Analogues: Stereoselective Synthesis and Studies on Their Conformational Properties

“…As part of our ongoing interest in the development of nucleosides with expanded sugar rings, , we herein describe the synthesis of several novel oxepane-based nucleosides that are excellent candidates for biological screening and building blocks for gene silencing oligonucleotides . The focus of this study is to use a common and versatile chiral synthetic intermediate to generate structurally diverse oxepane nucleosides.…”