1: N,N-dimethyl-formamide With trichlorophosphate T=0 - 20°C; Vilsmeier reaction; 0.25 h; Inert atmosphere; 2: 2-amino acetophenone T=60°C; Vilsmeier reaction; 4 h; Inert atmosphere;

trichlorophosphate in N,N-dimethyl-formamide T=0°C; Vilsmeier formylation; 5.5 h; Reflux;

trichlorophosphate T=90°C; Formylation; Vilsmeier cyclization;

methanol; sodium tetrahydroborate T=0 - 20°C; 3 h;