1: 70.5 percent / ozone, conc. HCl / H2O; methanol / -5 - 0 °C 2: 74.5 percent / dimethylformamide / 1 h / 80 °C View Scheme

1: 70.5 percent / ozone, conc. HCl / H2O; methanol / -5 - 0 °C 2: 74.5 percent / dimethylformamide / 1 h / 80 °C 3: 50.9 percent / NaOCH3 / dimethylformamide / 12 h / 80 - 90 °C View Scheme

With  hydrogenchloride; ozone in  methanol; water T=-5 - 0°C;