Boron Clusters − A New Entity for DNA‐Oligonucleotide Modification

Abstract

The carboranyl cluster is a new and versatile modifying entity for nucleotides and nucleic acids. Three types of carboranyl (−C 2 B 10 H 11 ) group-containing DNA-oligonucleotides are described: (1) CBMP-oligonucleotides, consisting of the carborane cage within an internucleotide linkage; (2) CDUoligonucleotides, containing the carborane cage attached to a nucleobase; and (3) 2Ј-CBM-oligonucleotides, with the carborane cage linked to a sugar residue at the 2Ј position. The method of synthesis and the physicochemical and biochemical features of these novel modifications are discussed, together with structure−property relationships. The carboranyl cluster-containing oligonucleotides form a crossover between (carba)borane chemistry and molecular

Ab initio quantum chemical study of electron transfer in carboranes

“…However, negligible, if any, difference is noted in the value of V AB between the localized (i.e., H AA 6 ¼ H BB ) and the average (i.e., H AA = H BB ) structure, justifying the validity of Condon approximation [17,18] used in deriving Eq. (2).…”

“…Carboranes are an important class of boron-containing rigid structures that have potential applications in medicinal drug design as hydrophobic pharmacophores [1], as antisense agents for antisense oligonucleotide therapy (AOT) [2], as boron carriers for boron neutron capture therapy (BNCT) [3][4][5], and as molecular probes for molecular medical diagnostics [6], among others. Recently, heteroisomeric diodes, based upon the chemical vapor deposition of different isomers of closo-dicarbadodecaborane, namely closo-1,2-dicarbadodecaborane (orthocarborane, C 2 B 10 H 12 ) and closo-1,7-dicarbadodecaborane (metacarborane, C 2 B 10 H 12 ), which have important applications as solid state neutron detectors have also been fabricated [7].…”

Nucleoside–Metallacarborane Conjugates for Base‐Specific Metal Labeling of DNA

“…In the case of T and dG a mixture of regioisomers, which is easily separable by chromatographic methods, is obtained, thus yielding a series of modifications containing met-cleoside conjugates is their application as versatile synthons for the synthesis of metal-bearing DNA-oligomers for various applications. [5,14,20] Here we describe a general method for the synthesis of metallacarborane derivatives of all four of the canonical nucleosides thymidine (T, 1 a), 2'-O-deoxycytidine (dC, 1 b), 2'-O-deoxyadenosine (dA, 1 c), and 2'-O-deoxyguanosine (dG, 1 d). The availability of this methodology makes studies of a broad spectrum of nucleoside conjugates bearing metals and incorporation of these metal centers into DNA-oligomers at designated locations possible.…”

“Chemical Ligation”: A Versatile Method for Nucleoside Modification with Boron Clusters

“…[2][3][4] Abstract: A general approach to the synthesis of nucleoside conjugates containing carborane and metallocarborane complexes, based on Huisgen 1,3-dipolar cycloaddition ("chemical ligation"), is described. Boron-clusterdonors bearing terminal azide or ethynyl groups were prepared in the ringopening reaction of dioxane-boroncluster adducts and an azide anion or suitable alkynol-derived alcoholate nucleophile.…”