1.1: hydrogenchloride; toluene-4-sulfonic acid / ethanol / 48 h / 20 °C 1.2: 10 - 20 °C 1.3: 0.75 h / 50 °C 2.1: potassium carbonate / water; acetone / 0.5 h / 5 °C 2.2: 1 h / 50 °C 2.3: 1 h / Reflux View Scheme