A convenient approach towards boron cluster modifications with adenosine and 2′-deoxyadenosine

Charge-Compensated Metallacarborane Building Blocks for Conjugation with Peptides

The cobalt bis(dicarbollide) complex [commo-3,3'-Co(1,2-C2 B9 H11 )2 ](-) has captured much attention in biochemical and medical contexts, in particular for the treatment of tumors by boron neutron capture therapy (BNCT). Derivatives of cobalt bis(dicarbollide) are commonly prepared through ring-opening reactions of cyclic oxonium ions, so the corresponding products are usually charged. Furthermore, attempts to incorporate cobalt bis(dicarbollide) into peptides are rare, despite obvious potential advantages. Here the synthesis of an imidazolium-based charge-compensated cobalt bis(dicarbollide) building block, which allows additional modifications with moieties of biochemical relevance, such as monosaccharides, is reported. Furthermore, conjugates of these building blocks with the Y1 -receptor-selective derivative of neuropeptide Y ([F(7) ,P(34) ]-NPY) retained excellent response to hY1 receptors found to be overexpressed in breast tumors and metastases.

Synthesis and the structure of 8-tetrahydrofuronium and 8-tetrahydropyronium derivatives of iron bis(dicarbollide)(-I) and their cleavage reactions

8-Tetrahydrofuronium and 8-tetrahydropyronium derivatives of iron bis(dicarbollide)(-I) were synthesized. Their reactions of ring cleavage by MeOH, N3(-), amines and 1,2-bis(diphenylphosphino)ethane were investigated. 8-Tetrahydrofuronium iron bis(dicarbollide)(-I) was found to be more active in these reactions in comparison with 8-tetrahydropyronium and 8-dioxonium species, respectively. The first conjugates of iron bis(1,2-dicarbollide)(-I) with 2'-deoxyadenosine modified via the C-8 position of the purine base were synthesized. Reactions of these oxonium compounds with 1,2-bis(diphenylphosphino)ethane (dppe) led to zwitter-ionic monophosphonium salts. One of these compounds has given rise to a novel ferracarborane/cobaltacarborane hybrid complex.

Cyanide free contraction of disclosed 1,4-dioxane ring as a route to cobalt bis(dicarbollide) derivatives with short spacer between the boron cage and terminal functional group

The 1,4-dioxane derivative of cobalt bis(dicarbollide) reacts with dialkylsulfides and triphenylphosphine to give the corresponding sulfonium and phosphonium derivatives.