Carborane isothiocyanates: synthesis, characterization and conjugation with N-nucleophiles

Abstract

A series of novel carborane isothiocyanates were synthesized via the reaction of carbon- or boron-substituted aminocarboranes with 1,1′-thiocarbonyldi-2(1H)-pyridone in CH₂Cl₂ under neutral conditions. The reactivity of synthesized isothiocyanates was studied in reactions with various N-nucleophiles including cyclohexylamine, aniline, aminobenzothiazole and a number of natural amino acids. As a result, the corresponding carborane thiourea derivatives were obtained in good yields demonstrating the efficiency of new isothiocyanates to be used for the introduction of the carborane cluster into the various structurally diverse compounds. The structure of all synthesized compounds was confirmed via IR spectroscopy, ¹H, ¹¹B and ¹³C NMR as well as mass spectrometry. The structures of some compounds were supported by X-ray structure determination.