1.1: potassium hydroxide / water; tetrahydrofuran; methanol / 10 h / 0 °C 1.2: 10 h / 0 - 20 °C 2.1: triethylamine; 2-hydroxy-pyridine / 48 h / 90 °C 3.1: trifluoroacetic acid / dichloromethane / 3 h / 20 °C View Scheme