1.1: N-ethyl-N,N-diisopropylamine / toluene; acetonitrile / 6.5 h / -35 - -25 °C 2.1: potassium tert-butylate; 1-ethyl-3-methylimidazolium chloride / dimethyl sulfoxide / 0.5 h / 20 °C 2.2: 0.5 h 3.1: sodium hydroxide; water / tetrahydrofuran; methanol / 10 - 20 °C View Scheme

1.1: N-ethyl-N,N-diisopropylamine / tetrahydrofuran / 1 h / -25 °C / Inert atmosphere 2.1: sodium hexamethyldisilazane / tetrahydrofuran / 1 h / -15 °C / Inert atmosphere 2.2: 7 h / -15 °C / Inert atmosphere 3.1: toluene / 20 - 80 °C 4.1: acetic acid / toluene; water / 0.33 h / 20 °C / pH 4 - 5 4.2: 0.5 h / 20 °C View Scheme