1: 99 percent / TsOH / benzene / 10 h / Heating 2: 1.) O3, 2.) NH2OH*HCl / 1.) MeOH, 0 deg C, 2.) 0 deg C, 30 min; reflux 3: 92 percent / H2SO4 / 0.75 h / 125 °C 4: 81 percent / 1,2-dichloro-ethane / 24 h / Ambient temperature View Scheme

1: 99 percent / TsOH / benzene / 10 h / Heating 2: 1.) O3, 2.) NH2OH*HCl / 1.) MeOH, 0 deg C, 2.) 0 deg C, 30 min; reflux View Scheme

1: 99 percent / TsOH / benzene / 10 h / Heating 2: 1.) O3, 2.) NH2OH*HCl / 1.) MeOH, 0 deg C, 2.) 0 deg C, 30 min; reflux 3: 92 percent / H2SO4 / 0.75 h / 125 °C View Scheme