1: 81.4 percent / M sodium methoxide / methanol / 5 h / Ambient temperature 2: 81.9 percent / zinc chloride / Ambient temperature 3: 78.9 percent / pyridine / 48 h / Ambient temperature 4: 85.5 percent / 60percent aq. acetic acid / 0.67 h / 98 °C 5: sodium methoxide / methanol View Scheme

acetic acid T=98°C; 0.5 h;