RESUMO
Hypervalent tellurium compounds (telluranes) are promising therapeutical agents with negligible toxicities for some diseases in animal models. The C-Te bond of organotellurium compounds is commonly considered unstable, disfavoring their applicability in biological studies. In this study, the stability of a set of telluranes composed of an inorganic derivative and noncharged and charged organic derivatives was monitored in aqueous media with 1H, 13C, and 125Te NMR spectroscopy and high-resolution mass spectrometry. Organic telluranes were found to be remarkably resistant and stable to hydrolysis, whereas the inorganic tellurane AS101 is totally converted to the hydrolysis product, trichlorooxytellurate, [TeOCl 3 ]-, which was also observed in the hydrolysis of TeCl 4 . The noteworthy stability of organotelluranes in aqueous media makes them prone to further structure-activity relationship studies and to be considered for broad biological investigations.
RESUMO
Internal bis-substituted propargylic diols were subjected to enzymatic kinetic resolution promoted by CAL-B. Employing a two round sequence EKR, mono- and bis-acetoxy propargylic products were obtained in a high enantiomeric ratio (E > 200). The efficiently resolved chiral 8b was applied in a concise synthesis of (S)-1b, an optically active natural product produced by fungi Clitocybe catinus.