Andrey Semioshkin

Cyclic oxonium derivatives of polyhedral boron hydrides and their synthetic applications.

Cyclic oxonium derivatives of polyhedral boron hydrides are a relatively new class of boron compounds. They have great potential for the modification of various types of organic and bioorganic molecules and the synthesis of compounds that could be used in different fields from the treatment of nuclear wastes to the treatment of cancer. In the present Perspective we would like to present an overview of the results of the preparation and synthetic application of these compounds.

Synthesis of conjugates of polyhedral boron compounds with tumor-seeking molecules for neutron capture therapy

Recent achievements in design and synthesis of boronated acids, amino acids, glycerols as well as conjugates of polyhedral boron hydrides (ortho-carborane, closo-dodecaborate and cobalt bis(dicarbollide)) with natural porphyrins, carbohydrates and nucleosides are described.

Synthesis and NMR spectra of the hydroxyundecahydro-closo-dodecaborate B12H11OH (2-) and its acylated derivatives

Tetrabutylammonium hydroxyundecahydro-closo-dodecaborate was obtained in high yield via [B12H11NMP]−(NMP =N-methylpyrrolidone) by the modified method. [Bi2H11OH]2− is easily acylated by aromatic acyl chlorides to give novel compounds [B12H11OCOAr]2− in high yields. All the compounds were characterized by standard and special NMR methods.

Interactions of carborane-containing electrophiles with triethyl phosphite. Synthesis of new carborane-containing phosphonates

The reactions ofo-carboran-l-ylethyl mesylates with triethyl phosphite and sodium diethyl phosphite were studied. Carborane-containing phosphonates were synthesized. The reaction ofo-carboranylacetyl chloride with triethyl phosphite affordedO,O-diethyl (E)-2-(o-carboran-l-yl)-1-(o-carboran-1-ylacetoxy) vinylphosphonate rather than oxo phosphonate.

New boron-containing 2′-deoxyadenosines

Conjugates of polyhedral boron hydrides with deoxyadenosine were synthesized by the opening of cyclic oxonium derivatives of closo-dodecaborate and cobalt bis(1,2-dicarbollide) with 2′-deoxyadenosine derivatives containing a nucleophilic group in the substituent at C(8). Biological studies of the derivatives obtained for cytotoxicity revealed that the derivatives based on closo-dodecaborate did not exhibit cytotoxicity. The conjugates obtained can be used in further biological trials as potential agents for boron neutron capture therapy of cancer.

SYNTHESIS OF DIALKOXY- AND ALKOXY-AMINO-DISUBSTITUTED DERIVATIVES OF B12H122-

Dichloromethoxymethane reacts with the sodium salt ofcloso-dodecahydrododecaborate Na2B12H12 to give disubstituted cluster, which readily decomposes when treated with various reagents. This cluster reacts with water, forming the previously described 1,7-B12H10(OH)22−reaction with alcohols results in a novel 1,7-dialkoxy derivative, whereas interaction with morpholine in acetone solution affords the novel anion, 1-O-I-Pri-7-O(CH2CH2)N-B12H102−. All of these derivatives were isolated as cesium salts and characterized by one- and two-dimensional NMR techniques.

CCDC 1499776: Experimental Crystal Structure Determination

Related Article: Julia Laskova, Aleksandra Kozlova, Ivan Ananyev, Vladimir Bregadze, Andrey Semioshkin|2017|J.Organomet.Chem.|834|64|doi:10.1016/j.jorganchem.2017.02.009

Syntheses based on 1-iodo-7-(dioxonium)decahydro-closo-dodecaborate

The nucleophilic cleavage of 1-iodo-7-(dioxonium)decahydro-closo-dodecaborate (1) with sodium azide and thymidine or guanosine derivatives was studied. Compound 1 exhibits higher reactivity compared to the unsubstituted dioxonium derivative. The reactions of 1[NBu4] with 3′,5′-di(tert-butyldimethylsilyl)thymidine and 8-mercaptoguanosine afford the corresponding boron-containing nucleosides.