Preparation of the 2′-Deoxynucleosides of 2,6-Diaminopurine and Isoguanine by Direct Glycosylation

A Chemical Approach to Introduce 2,6-Diaminopurine and 2-Aminoadenine Conjugates into Oligonucleotides without Need for Protecting Groups

We report a simple, postsynthetic strategy for synthesis of oligonucleotides containing 2,6-diaminopurine nucleotides and 2-aminoadenine conjugates using 2-fluoro-6-amino-adenosine. The strategy allows introduction of 2,6-diaminopurine and other 2-amino group-containing ligands. The strongly electronegative 2-fluoro deactivates 6-NH₂ obviating the need for any protecting group on adenine, and simple aromatic nucleophilic substitution of fluorine makes reaction with aqueous NH₃ or R-NH₂ feasible at the 2-position.

Chemical and chemoenzymatic stereoselective synthesis of β-nucleosides and their analogues

β-Nucleosides are fundamental building blocks of biological systems that are widely used as therapeutic agents for treating cancer and viral infections among others. In the last two years, nucleoside analogues...

Site-Selective and Stereoselective C-H Functionalization of N-Cyclopropylamides via a Directed Remote Metalation Strategy

A new methodology for site-selective and stereoselective C-H functionalization of aminocyclopropanes via directed remote lithiation has been developed. Treatment of N-directing group (DG = pivaloyl, tetramethylsuccinimidoyl) arylcyclopropanes with t-BuLi results in a clean β-lithiation and, following quench with electrophiles, leads to a range of cyclopropane derivatives. Sequential double lithiation-methylation to give a dimethylated cyclopropane has been achieved. X-ray, NMR, and computational studies allow rationalization of syn-DG β-deprotonation selectivity via a DG-lithium base coordinated complex.

Biotransformation of 2,6-diaminopurine nucleosides by immobilized Geobacillus stearothermophilus

An efficient and green bioprocess to obtain 2,6-diaminopurine nucleosides using thermophilic bacteria is herein reported. Geobacillus stearothermophilus CECT 43 showed a conversion rate of 90 and 83% at 2 h to obtain 2,6-diaminopurine-2'-deoxyriboside and 2,6-diaminopurine riboside, respectively. The selected biocatalyst was successfully stabilized in an agarose matrix and used to produce up to 23.4 g of 2,6-diaminopurine-2'-deoxyriboside in 240 h of process. These nucleoside analogues can be used as prodrug precursors or in antisense oligonucleotide synthesis.