1.1: sulfuric acid / Reflux 2.1: tin(ll) chloride / 20 °C 3.1: hydrazine hydrate / ethanol / 3 h / 150 °C 3.2: 0.5 h / Reflux 4.1: N,N-dimethyl-aniline; trichlorophosphate / chloroform / 120 °C 5.1: tetrahydrofuran / -78 °C View Scheme

1.1: hydrazine hydrate / ethanol / 3 h / 150 °C 1.2: 0.5 h / Reflux 2.1: N,N-dimethyl-aniline; trichlorophosphate / chloroform / 120 °C 3.1: tetrahydrofuran / -78 °C View Scheme

1.1: tin(ll) chloride / 20 °C 2.1: hydrazine hydrate / ethanol / 3 h / 150 °C 2.2: 0.5 h / Reflux 3.1: N,N-dimethyl-aniline; trichlorophosphate / chloroform / 120 °C 4.1: tetrahydrofuran / -78 °C View Scheme

in tetrahydrofuran T=-78°C;

in pyridine 20 h;

hydrogenchloride T=100°C; 6 h;