acetic acid T=60°C; 0.5 h;

1: 88 percent / pyridine / 1.5 h / Ambient temperature 2: 80 percent / sodium sulfide / dioxane; H2O / 6 h / 90 °C 3: 77 percent / 80percent acetic acid / 0.5 h / 60 °C View Scheme

1: 80 percent / sodium sulfide / dioxane; H2O / 6 h / 90 °C 2: 77 percent / 80percent acetic acid / 0.5 h / 60 °C View Scheme