sodium sulfide; sulfur 48 h; Heating;

1: With (benzotriazo-1-yloxy)tris(dimethylamino)phosphonium hexafluorophosphate; N-ethyl-N,N-diisopropylamine in dichloromethane T=20°C; 0.5 h; 2: With Lawesson's reagent in ethylene glycol dimethyl ether T=80°C; 2 h;