1.1: pyridine; 4-(N,N-dimethlyamino)pyridine / dichloromethane / 1.25 h / 20 °C / |Inert atmosphere 2.1: dichloromethane / 2 h / 20 °C / |Inert atmosphere 3.1: citric acid / dichloromethane 3.2: 37 °C / pH 7.4 / |Inert atmosphere 4.1: water / |Inert atmosphere View Scheme

1.1: pyridine; 4-(N,N-dimethlyamino)pyridine / dichloromethane / 1.25 h / 20 °C / |Inert atmosphere 2.1: dichloromethane / 2 h / 20 °C / |Inert atmosphere 3.1: citric acid / dichloromethane 3.2: 37 °C / pH 7.4 / |Inert atmosphere View Scheme