反应条件
1.1: N-ethyl-N,N-diisopropylamine / toluene; acetonitrile / 40 °C 1.2: 2.5 - 3 h / -27 °C 2.1: sodium methylate / N,N-dimethyl-formamide; methanol / 1.5 h / -10 °C / Inert atmosphere 2.2: 15 h / -5 °C / Inert atmosphere 2.3: 0.17 - 0.25 h 3.1: ethyl acetate / 0.5 h / 20 °C 4.1: 2,3-dihydroxybutanedioic acid / dichloromethane; water / 0.25 - 0.33 h 4.2: 0.08 - 0.17 h View Scheme
