1: N-bromosuccinmide / N,N-dimethyl-formamide / 0.5 h / 0 °C 2: N-ethyl-N,N-diisopropylamine / N,N-dimethyl-formamide / 1 h / 20 °C View Scheme

1.1: N-bromosuccinmide / N,N-dimethyl-formamide / 0.5 h / 0 °C 2.1: N-ethyl-N,N-diisopropylamine / N,N-dimethyl-formamide / 1 h / 20 °C 3.1: potassium permanganate / acetone / 20 - 40 °C 4.1: sodium hydroxide / water; methanol / 2 h / 20 °C 4.2: pH 2 View Scheme