1: POCl3, N,N-dimethylaniline / 3 h / Heating 2: dioxane / 6 h / Heating View Scheme

1: SnCl4 / CS2 / 2 h / Ambient temperature 2: conc. H2SO4 / 4 h / Ambient temperature 3: KOH, hydrazine hydrate / bis-(2-hydroxy-ethyl) ether / 2 h / Heating 4: toluene / 0.5 h / Heating 5: polyphosphoric acid / 1 h / 130 °C 6: POCl3, N,N-dimethylaniline / 3 h / Heating 7: dioxane / 6 h / Heating View Scheme

1: toluene / 0.5 h / Heating 2: polyphosphoric acid / 1 h / 130 °C 3: POCl3, N,N-dimethylaniline / 3 h / Heating 4: dioxane / 6 h / Heating View Scheme

1: KOH, hydrazine hydrate / bis-(2-hydroxy-ethyl) ether / 2 h / Heating 2: toluene / 0.5 h / Heating 3: polyphosphoric acid / 1 h / 130 °C 4: POCl3, N,N-dimethylaniline / 3 h / Heating 5: dioxane / 6 h / Heating View Scheme

1: polyphosphoric acid / 1 h / 130 °C 2: POCl3, N,N-dimethylaniline / 3 h / Heating 3: dioxane / 6 h / Heating View Scheme

1: conc. H2SO4 / 4 h / Ambient temperature 2: KOH, hydrazine hydrate / bis-(2-hydroxy-ethyl) ether / 2 h / Heating 3: toluene / 0.5 h / Heating 4: polyphosphoric acid / 1 h / 130 °C 5: POCl3, N,N-dimethylaniline / 3 h / Heating 6: dioxane / 6 h / Heating View Scheme

in 1,4-dioxane 6 h; Heating;