Synthesis of Substituted Derivatives of closo-Decaborate Anion with a Peptide Bond: The Way towards Designing Biologically Active Boron-Containing Compounds

A novel scheme of multi-step synthesis for N-borylated dipeptide R-GlyPheOEt is proposed, which is based on the nucleophilic addition of amino acid derivatives to the [2-B10H9NCCH3](-) anion. The products obtained at each step were studied by NMR, IR spectroscopy, and ESI mass spectrometry. The single-crystal structure of (NBu4)[2-B10H9NH=C((NH2CH2COOC4H9)-C-t)CH3] was identified by XRD.