Peptides are molecules that have sequences of different lengths composed from different natural or modified amino acids that are connected by an amide bond. With modifications, we can introduce different functional groups into the peptide and thus influence its structure. For example, in this way we can increase its stability, influence its reactivity, solubility, and activity. We focused on introducing a non-natural carborane fragment to the peptide chain. The carborane cluster consists of 12 atoms arranged in the shape of an icosahedron, containing 2 carbon atoms that can be in different positions; thus distinguishing ortho, meta, and para isomers, which differ in stability and reactivity. The introduction of carborane fragments to a larger peptide or antibody is mentioned as a promising avenue in cancer treatment through Boron Neutron Capture Therapy (BNCT). Due to its high-boron content, carboranes are seen as an ideal boron cargo for BNCT. As part of the master's thesis, we synthesized 8 carborane compounds, 2 model peptides and 2 carborane peptide conjugates. The yields were good in all stages of synthesis, despite losses during purification on chromatographic columns. The model peptides were synthesized in a very pure form using an automated solid-phase synthesis methodology. This model peptides served for synthesis of two carborane conjugates using developed carborane NHS reagents. This demonstrated the ability of developed reagents as carborane conjugation to a peptide, which could be later also demonstrated on an antibody – a larger biological molecule.
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