Synthesis of the first conjugates of 5-ethynyl-2′-deoxyuridine with closo-dodecaborate and cobalt-bis-dicarbollide boron clusters

• DOI: 10.1016/j.tet.2013.06.100
• Publication Date: 2013-07-04T13:01:44Z
• Authors: Andrey Semioshkin; Anna Ilinova; Irina Lobanova; Vladimir Bregadze; Edyta Paradowska; Mirosława Studzińska; Agnieszka Jabłońska; Zbigniew J. Lesni...
• Keywords: Oxonium ion; Reactivity; Deoxyuridine; Conjugate

A new 2′-deoxyuridine modification, 3′,5′-bis-(dimethyl-tert-butylsilyl)-5-(3-(2-(dimethylamino)ethoxy)-3-methylbutyn-1-yl)-2′-deoxyuridine was effectively synthesized in four easy steps. Its reactivity toward a range of cyclic oxonium adducts of closo-dodecaborate and cobalt-bis-dicarbollide boron clusters was studied. The cleavage reactions of cluster oxonium rings by the N,N-dimethylamino group of the modified nucleoside led to 5-ethynyl-2′-deoxyuridine conjugates with [B12H12]2− and [Co(C2B9H11)2]−, respectively. Cytotoxicity of these new conjugates in several cell lines was examined. Closo-dodecaborate conjugates showed low cytotoxicity in all examined cell lines, an advantageous and preferred property for potential boron delivering drugs for the boron neutron capture therapy (BNCT) of tumors.