1: TFA; acetone 2: 96 percent / Et3N / 18 h / 20 °C 3: TFA; acetone 4: 95 percent / Et3N / 18 h / 20 °C 5: aq. HCl; acetone / dioxane 6: 95 percent / HCOONa; Ac2O / 1.33 h / 0 - 20 °C 7: 95 percent / aq. NaOH / methanol / 0.33 h / 20 °C View Scheme

Multistep reaction;