sodium L-ascorbate in methanol; water; acetone 5 h;

triethylamine in benzene 3 h; Heating;

sodium sulfide T=100°C;

in 1,4-dioxane; water react. under N2 (deoxygenated solns.); addn. of CrSO4 in distd. H2O to a slight excess of Te-compd. in dioxane at room temp.; extn. of Te2R2 into diethyl ether, washing of green-coloured aq. layer with ether (several times), concn. under reduced pressure at 30°C until pptn. occurs, filtration, washing with H2O, drying over P2O5 in vac.; elem. anal.;

triphenylphosphine in diethyl ether under N2, excess PPh3, stirred for 1 h at room temp.; filtered, filtrate evapd. to dryness, detn. by (1)H-NMR;

triphenylphosphine in diethyl ether stirring under N2 for 1 h at room temp.;; filtered, evapd.; identified by NMR-spectroscopy;;

sodium sulfide

sodium sulfide

sodium sulfide

TeCl4 Reduktion des Reaktionsproduktes mit alkal. Na2S2O4-Loesung;