(77)Se and (125)Te 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 (1)H, (13)C, (77)Se and (125)Te 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. (77)Se and (125)Te 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.