acide p-toluenesulfonique in xylene Heating;

1: N,N-dimethyl-formamide With phosphorus oxytribromide in chloroform T=0°C; 0.5 h; 2: 3-oxo-2,3-dihydrobenzolt;bgt;selenophene in chloroform T=70°C; Vilsmeier-Haack-Arnold reaction; 6 h;