Nucleobases with Designed Patterns of Hydrogen Bonding

Preparation of pyridine-stretched 2'-deoxyhypoxanthosine phosphoramidite

“…As the starting point for synthesis of the nucleoside intermediate 15, we selected the well-known and widely used Hoffer sugar (2-deoxy-3,5-di-O-(p-toluoyl)-α-D-erythro-pentofuranosyl chloride) 10. 20 It is prepared as a single anomer in three steps from 2-deoxy-α/β-D-erythro-pentopyranose 7 (Scheme 1). A typical Hoffer procedure 21 gives the sugar 10 as a solid that must then be glycosylated otherwise decomposition occurs on storage beyond two weeks, even under vacuum.…”

A concise synthesis of isoguanine 2ʹ-deoxyriboside and its adenine-like triplex formation when incorporated into DNA

“…At the nucleoside level, hydrogenolysis of the 2-benzyloxy group 34 would give a concise route to 2'-deoxyisoguanosine from non-nucleoside precursors. At the DNA level, removal of the 2-allyloxy group using Noyori conditions 35 would give isoguanine 29 (Figure 2 right) for the study of its triplex-forming properties and also allow comparison between A, isoG, B and L. As the starting point for synthesis of the nucleoside intermediate 5, 36 we selected the well-known and widely used 6,29,[37][38][39][40][41] Hoffer sugar 2 (2-deoxy-3,5-di-O-(p-toluoyl)-α-D-erythro-pentofuranosyl chloride). 42 Recently, we reported an improved synthesis of the Hoffer sugar that was achieved without need for distillation or chromatographic separation of intermediates, or the use of gaseous HCl.…”