1: carbon disulfide; diethyl malonate With tetrabutylammomium bromide; potassium carbonate in water T=20°C; 2: ethylene dibromide in water T=20°C; 8 h;

potassium carbonate in N,N-dimethyl-formamide T=20°C; Condensation; cyclization; 5 h;

diethyl ether Behandeln des Reaktionsgemisches mit 1,2-Dibrom-aethan;