Nucleoside bearing boron clusters and their phosphoramidites – building blocks for modified oligonucleotide synthesis

Abstract

This paper describes a general method for the synthesis of four canonical nucleosides T, dC, dA and dG and their phosphoramidites suitable for automated synthesis of DNA modified with a carborane cage. A boron cluster in the form of an electroneutral, lipophilic 1,2-dicarba-closododecaborane (C2B9H11) or negatively charged, redox-active 7,8-dicarba-nido-undecaborate ion (C2B9H12(-1)) was used as a modifying unit. The method is based on the "click chemistry" type Huisgen-Sharpless-Meldal reaction. All boron cluster-nucleoside conjugates have been characterized electrochemically, they have shown different redox potentials allowing for selective electrochemical identification of individual nucleosides in the mixture. There is also the first description of the crystallographic structure of the boron cluster-nucleoside conjugate: N 3 -{[(ocarboran-1-yl)propyl]-1N-1,2,3-triazol-4-yl}methylenethymidine.

Small‐Molecule Kinase‐Inhibitors‐Loaded Boron Cluster as Hybrid Agents for Glioma‐Cell‐Targeting Therapy

“…The first approach consisted in the use of [1,2,3]triazolylpropyl connector generated by 1,3‐dipolar cycloaddition, in the presence of CuSO 4 ⋅ 5 H 2 O and sodium ascorbate, giving hybrids 5 , 6 , 11 , and 12 in good yield (69–78 % after purification). The intermediate carboranylazides ( 3 , 4 , 9 , and 10 ) were selected to introduce chemodiversity to the final compounds, that is, un‐substituted and methyl‐substituted 1,2‐ and 1,7‐ closo ‐carboranyl frameworks. The second approach involved the transformation of ethynyl‐erlotinib group into an erlotinib‐ethynylbenzyl connector (Scheme ), via Sonogashira cross‐coupling in presence of CuI and [PdCl 2 (PPh 3 ) 2 ], generating compounds 15 , 16 , 19 , and 20 in 35–49 % yield, after purification.…”

Carborane‐Containing Matrix Metalloprotease (MMP) Ligands as Candidates for Boron Neutron‐Capture Therapy (BNCT)

“…[30] We therefore elected to employ [3 + 2] click chemistry to attach boron clusters to the alkyne moiety of 9. [31,32] Others have employed click chemistry to append carboranes toward the preparation of new BNCT agents. [13,33] The preparation of the requisite carboranyl propyl azide is shown below in Scheme 2.…”

DNA Modified with Boron–Metal Cluster Complexes [M(C2B9H11)2]—Synthesis, Properties, and Applications

“…Expanding these works, we have developed a general method for the synthesis of four canonical nucleosides T, dC, dA, and dG modified with 1,2-dicarba- closo -dodecaborane (C 2 B 10 H 11 ) cage, and their phosphoramidites, suitable for automated synthesis of DNA [ 27 ]. The modified nucleoside monomers bearing boron cluster were prepared from suitable 5-ethynyl derivatives in one-step reaction using cooper(I)-catalyzed Huisgen–Meldal–Sharpless 1,3-dipolar cycloaddition of azides and alkynes to give triazoles.…”