1: With diethylamine in N,N-dimethyl-formamide; acetone T=40 - 45°C; 1.08333 h; 2: in n-heptane; N,N-dimethyl-formamide 2 h; 3: With potassium carbonate in n-heptane; N,N-dimethyl-formamide T=90 - 95°C; Inert atmosphere;