Modular triazine-based carborane-containing carboxylic acids - synthesis and characterisation of potential boron neutron capture therapy agents made of readily accessible building blocks

Based on a modular combination of s -triazine, the well-known 9-mercapto-1,7-dicarba- closo -dodecaborane(12) and commercially available carboxylic acids, namely thioglycolic acid, glycine, and N α -Boc- l -lysine, several carboxylic acid derivatives were synthesised and fully characterised. The thioglycolic acid derivative was introduced into a peptide hormone by solid phase peptide synthesis. High activity and selective internalisation into peptide receptor-expressing cells was observed. With a very high boron content of twenty boron atoms, these derivatives are interesting as selective Boron Neutron Capture Therapy (BNCT) agents. Boron-rich carboxylic acid derivatives were synthesised as coupling partners for tumour-selective biomolecules with applications as selective BNCT agents.