acetic acid in toluene T=95°C; 0.5 h;

1: H2SO4 / dioxane / 17 h / Ambient temperature 2: 78 percent / Et3N, DCC, 1-hydroxybenzotriazole / tetrahydrofuran / Ambient temperature 3: TFA / 1 h / Ambient temperature 4: 80 percent / AcOH / toluene / 0.5 h / 95 °C View Scheme

1: 78 percent / Et3N, DCC, 1-hydroxybenzotriazole / tetrahydrofuran / Ambient temperature 2: TFA / 1 h / Ambient temperature 3: 80 percent / AcOH / toluene / 0.5 h / 95 °C View Scheme

1: 78 percent / Et3N, DCC, 1-hydroxybenzotriazole / tetrahydrofuran / Ambient temperature 2: TFA / 1 h / Ambient temperature 3: 80 percent / AcOH / toluene / 0.5 h / 95 °C View Scheme

1: TFA / 1 h / Ambient temperature 2: 80 percent / AcOH / toluene / 0.5 h / 95 °C View Scheme

citric acid T=80°C; pH=2.60; Kinetics; Further Variations:pH-values;