thionyl chloride in N,N-dimethyl-formamide T=120°C; 3 h;

1.1: LDA / tetrahydrofuran / 1 h / -78 °C 1.2: tetrahydrofuran / -78 - 20 °C 2.1: SOCl2 / 3 h / 80 °C 3.1: aq. NH3 / tetrahydrofuran / 20 °C 4.1: SOCl2 / dimethylformamide / 16 h / 115 °C View Scheme