1.1: ammonia / methanol; dichloromethane / 0.5 h / 0 °C / |Inert atmosphere 2.1: ammonia / methanol; dichloromethane / 1 h / 0 °C / |Inert atmosphere 2.2: 20 °C / |Inert atmosphere 3.1: sodium methylate / methanol / 4.5 h / |Cooling with ice; |Inert atmosphere 4.1: β-galactosidase; magnesium chloride / dimethyl sulfoxide / 37 °C / pH 7.4 / |Enzymatic reaction View Scheme