1: 76.3 percent / pyridine / 3.5 h / 13 °C 2: 13.8 percent / KMnO4, 18-crown-6 / benzene / 3 h / 17 °C 3: 98.6 percent / 30percent aq. KOH / ethanol / 30 h / 55 - 60 °C 4: 58.6 percent / 40percent NaOH / methanol / 2 h / Heating View Scheme

With  phosphorus pentoxide in  xylene T=140°C; 3.5 h;   

Multi-step reaction with 2 steps 1: 76.3 percent / pyridine / 3.5 h / 13 °C2: 13.8 percent / KMnO4, 18-crown-6 / benzene / 3 h / 17 °C