Conjugates of polyhedral boron compounds with carbohydrates

Conjugates of β-lactosylamine derivatives bearing terminal amino groups in aglycon with ortho-carboranylacetic acid were synthesized. Five glycoconjugates with spacers of different length (from 9 to 18 atoms) and hydrophilicity containing di-, tri-, and pentapeptide fragments constructed of glycine and serine residues and spacers incorporating ethylenediamine and tartaric acid or tertiary amine residues were prepared Dedicated to the memory of outstanding chemist and biochemist V. N. Shibaev. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 2033–2036, October, 2007.     

Electrochemical iodination of C-methyl derivatives of dodecahydro-7,8-dicarba-nido-undecaborate anion

By electrochemical iodination of potassium 7-methyl-7,8-dicarba-nido-undecaborate and potassium 7,8-dimethyl-7,8-dicarba-nido-undecaborate, their monoiodine derivatives (extracted as tetramethylammonium salts) are synthesized. Their structure is confirmed by NMR and IR spectra and also by elemental analysis data.     

Derivatives of the closo-dodecaborate anion and their application in medicine

The paper presents a comparative analysis of the possibilities and characteristic features of the application of various polyhedral boron compounds, viz., the closo-decaborate anion [B₁₀H₁₀]^2–, the closo-dodecaborate anion [B₁₂H₁₂]^2–, the carba-closo-dodecaborate anion [CB₁₁H₁₂]^–, carboranes C₂B₁₀H₁₂, and the bis(dicarbollide) complexes [M(C₂B₉H₁₁)₂]^– (M = Fe, Co, or Ni), in boron neutron capture therapy (BNCT) for cancer. The requirements on compounds used in BNCT are formulated and the advantages of the application of the closo-dodecaborate anion are considered. The data on the synthesis of various derivatives of the closo-dodecaborate anion, which either already found use in BNCT or are most promising in this field, are summarized. The possibilities of the application of agents derived from the closo-dodecaborate anion in medical diagnostics are discussed.     

Crown compounds for anions. Sandwich complex of cyclic trimeric perfluoro-o-phenylenemercury with [B12H11SCN]2– anion

The reaction of cyclic trimeric perfluoro-o-phenylenemercury (o-C₆F₄Hg)₃ (1) with the polyhedral [B₁₂H₁₁SCN]^2– anion in THF at 20 °C affords the {[(o-C₆F₄Hg)₃](B₁₂H₁₁SCN)}^2– (4) and {[(o-C₆F₄Hg)₃]₂(B₁₂H₁₁SCN)}^2– (5) complexes. Complex 5 was isolated as the tetrabutylammonium salt. X-ray diffraction analysis showed that this complex has a bent-sandwich structure in which the [B₁₂H₁₁SCN]^2– anion is located between the planes of two molecules 1 and is coordinated to both these molecules through B—H—Hg bridges and S—Hg bonds. The stability constants of complexes 4 and 5 in THF (20 °C), which were determined from the IR spectroscopic data, are 16 L mol^–1 and 992 L² mol^–2, respectively.     

Reaction of exo-nido-ruthenacarborane [Cl(Ph3P)2Ru]-5,6,10-(μ-H)3-10-H-7,8-C2B9H8 with bromine

The reaction of bromine with exo-nido-ruthenacarborane [Cl(Ph₃P)₂Ru]-5,6,10-(-H)₃-10-H-7,8-C₂B₉H₈ (1) led to the replacement of the chlorine atom by the bromine atom in the octahedral environment of the ruthenium atom rather than to the substitution in the carborane cage. The structure of [Br(Ph₃P)₂Ru]-5,6,10-(-H)₃-10-H-7,8-C₂B₉H₈ was established by NMR and IR spectroscopy and X-ray diffraction analysis.     

Synthesis of Schiff bases and benzylamino derivatives containing [1-B<Subscript>10</Subscript>H<Subscript>9</Subscript>NH<Subscript>3</Subscript>]<Superscript>−</Superscript> anion

Reactions of an amino derivative of the closo-decaborate anion [1-B₁₀H₉NH₃]^– with aromatic aldehydes afforded Schiff bases [1-B₁₀H₉NH=CHAr]^– (Ar=Ph, C₆H₄-2-OMe, or C₆H₄-4-NHCOMe). The reduction of the latter with sodium borohydride gave the corresponding benzylamino derivatives [1-B₁₀H₉NH₂CH₂Ar]^–.Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 2004–2007, September, 2004.     

A novel approach to the synthesis of amino acids based on cobalt bis(dicarbollide)

A novel approach to the synthesis of boron-containing amino acids based on ring opening of cyclic oxonium derivatives of polyhedral boron hydrides under the action of the terminal functional groups of natural amino acids was proposed. This approach was successfully implemented for the synthesis of cobalt bis(dicarbollide) — tyrosine conjugate.     

Crown compounds for anions: sandwich and half-sandwich complexes of cyclic trimetric perfluoro-o-phenylenemercury with polyhedral closo-[B10H10]2- and closo-[B12H12]2- anions

It has been shown by IR and NMR spectroscopy that cyclic trimeric perfluoro-o-phenylenemercury (o-C6F4-Hg)3 (1) is capable of binding closo-[B10H10]2- and closo-[B12H12]2- anions to form complexes [[(o-C6F4Hg)3](B10-H10)]2- (2), [[(o-C6F4Hg)3]2(B10H10)]2-(3), [[(o-C6F4Hg)3](B12H12)]2- (4), and [[(o-C6F4Hg)3]2(B12H12)]2- (5). According to IR data, the bonding of the [B10H10]2- and [B12H12]2- ions to the macrocycle in these complexes is accomplished through the formation of B-H-Hg bridges. Complexes 2, 3, and 5 have been isolated in analytically pure form and have been characterized by spectroscopic means. X-ray diffraction studies of 3 and 5 have revealed that these compounds have unusual sandwich structures, in which the polyhedral di-anion is located between the planes of two molecules of 1 and is bonded to each of them through two types of B-H-Hg bridges. One type is the simultaneous coordination of a B-H group to all three Hg atoms of the macrocycle. The other type is the coordination of a B-H group to a single Hg atom of the cycle. According to X-ray diffraction data, complex 2 has an analogous but half-sandwich structure. The obtained complexes 2-5 are quite stable; their stability constants in THF/acetone (1:1) at 20 degrees C have been determined as 1.0 x 10(2)Lmol(-1), 2.6 x 10(3)L(2)mol(2), 0.7 x 10(2)Lmol(-1), and 0.98 x 10(3)L(2)mol(-2), respectively.     

Novel types of boronated chlorin e6 conjugates via ‘click chemistry’

Conjugates of chlorin e₆ with closo‐dodecaborate and cobalt bis(dicarbollide) anions were synthesized for the first time in high yields using the advanced ‘click’ methodology. In vitro study on A549 human lung adenocarcinoma cells revealed that the synthesized boronated conjugates are able to penetrate and accumulate in cancer cells, but their intracellular concentration is not sufficient for effective photodynamic and boron neutron capture therapy of cancer. Copyright © 2009 John Wiley & Sons, Ltd.     

Direct electrochemical synthesis of anionic complexes of thallium halides

Conclusion Using a platinum cathode and thallium anode, electrolysis of solutions containing halogens results in the formation of anionic complexes of univalent and trivalent thallium depending on the nature of the halogen and electrolyte.Deceased.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 5, pp. 1106–1108, May, 1987.