1.1: sodium hydroxide / tetrahydrofuran; water / 1.4 h / 0 - 5 °C 2.1: lithium methanolate / methanol / 66 h / 0 - 20 °C / Inert atmosphere 3.1: palladium 10 on activated carbon; hydrogen / methanol / 18 h / 20 °C 4.1: sodium hydroxide / tetrahydrofuran; water / 20 °C / Heating 4.2: pH 2 - 3 View Scheme