1: 1.) NaOCH3 / 1.) CH3OH, RT, 0.5 h, 2.) CH3OH, RT, overnight 2: aq. NaOH / 2 h / 60 °C 3: 1.) Mg / 1.) THF, 2.) THF, 30 deg C, 0.5 h 4: 79 percent / aq. oxalic acid / acetone / 1 h / Ambient temperature 5: KHSO4 / 180 °C View Scheme

1: 1.) NaOCH3 / 1.) CH3OH, RT, 0.5 h, 2.) CH3OH, RT, overnight 2: aq. NaOH / 2 h / 60 °C 3: 1.) Mg / 1.) THF, 2.) THF, 30 deg C, 0.5 h 4: 79 percent / aq. oxalic acid / acetone / 1 h / Ambient temperature View Scheme