Substituted monocarbon carboranes involving thiol, disulfide or dimethyl sulfide ligands

Abstract

New sulfur-substituted derivatives of closo- and nido-monocarbon carboranes have been synthesised for their potential application in ¹⁰B neutron capture therapy of tumours. The compounds 7-Me₃N-4(6)-HS-nido-7-CB₁₀H₁₁ and 4,4′-, 6,6′- and 4,6′-S₂(7-Me₃N-nido-7-CB₁₀H₁₁)₂ were obtained by Friedel-Crafts substitution of 7-Me₃N-nido-7-CB₁₀H₁₂ with S₂Cl₂; high-temperature boron insertion and methylation of the products gave 1-Me₂N-2-Me₂S-closo-1-CB₁₁H₁₀ as a result of a cluster rearrangement process. Its structure has been confirmed by X-ray crystallography.