77Se and 125Te NMR spectroscopy on a selectivity study of organochalcogenanes with l-amino acids

Abstract

The hypervalent selenium- and tellurium-containing compounds (halo-organoselenuranes and halo-organotelluranes) were treated with amino acids to evaluate their reactivity and chemoselectivity by ¹H, ¹³C, ⁷⁷Se and ¹²⁵Te NMR spectroscopy. The study of forced thermal stability was performed and analyzed by NMR. The organotelluranes remained stable at temperatures around 60 °C but in the case of organoselenuranes, there was formation of new products at 37 °C as a result of halogen loss. ⁷⁷Se and ¹²⁵Te NMR spectroscopy has proved to be a very efficient and fast technique to evidence the high selectivity of organochalcogenanes against L-amino acids, specific to L-cysteine.