1: 63 percent / N,N-diethylaniline / 2 h / Heating 2: 82 percent / AcONa / 1 h / Heating 3: 74 percent / bromine, acetic acid / 0.5 h / Ambient temperature 4: 39 percent / KOH / ethanol / 1.5 h / Heating View Scheme

1: 63 percent / N,N-diethylaniline / 2 h / Heating 2: 1.) O3, 2.) H2 / 2.) 10percent Pd/CaCO3 / 1.) EtOAc, 2.) EtOAc 3: 85percent aq. H3PO4 / 0.5 h / 100 °C View Scheme