1: dichlorodicyanobenzoquinone / dioxane / 15 h / Ambient temperature 2: p-toluenesulfonic acid / CH2Cl2 / 0.5 h / Ambient temperature 3: 72 percent / sodium hydroxide, hydrogen peroxide / methanol; H2O / 1.5 h / Ambient temperature 4: lithium / liquid ammonia; tetrahydrofuran / 1.5 h / -78 °C 5: N,N-diethylcyclohexylamine / dioxane / 1.) 50 deg C, 6 h; 2.) 80 deg C, 2 h 6: aq. HCl; tetrahydrofuran; methanol / Ambient temperature 7: 73 percent / pyridine / 0.5 h / 0 °C 8: 85 percent / dimethylsulfoxide / 4 h / 90 - 100 °C 9: potassium hydroxide / H2O; ethanol / 2 h / Heating 10: methanol; diethyl ether / 1 h / Ambient temperature 11: 81 percent / tetrahydrofuran / 1.) 0 deg C, 30 min; 2.) rt, 4.5 h 12: 82 percent / aq. HCl; tetrahydrofuran / 72 h / Ambient temperature 13: 74 percent / pyridine 14: N-bromosuccinimide / CCl4 / 0.33 h / Heating 15: tetra-n-butylammonium fluoride / tetra-n-butylammonium bromide / tetrahydrofuran 16: potassium hydroxide / tetrahydrofuran; methanol View Scheme