1: 2 h / 90 - 95 °C 2: 25 percent / H2O / -5 deg C, overnight View Scheme

1: 1.) acetic anhydride, 2.) 12percent aq. HCl / 1.) reflux, 60 min, 2.) reflux, 4 h 2: 80 percent / 1.) 70percent HClO4, CrO3 / aq. acetic acid / 72 h / Ambient temperature View Scheme

1: 58 percent / 3 h / Heating 2: 72 percent / 10percent HCl / Heating 3: 51 percent / polyphosphoric acid / 0.67 h / 90 - 100 °C 4: N-bromoacetamide, AcOH / 3 h / Ambient temperature 5: 79 percent / MeONa / tetrahydrofuran / 4 h / Ambient temperature 6: N-bromosuccinimide, azoisobutyronitrile / CCl4 / 0.67 h / 60 - 70 °C 7: 62 percent / MeONa / tetrahydrofuran / 1) 0 deg C, 1 h, 2) rt, 3 h 8: trifluoroacetic acid / CDCl3 View Scheme

1: 58 percent / 3 h / Heating 2: 72 percent / 10percent HCl / Heating 3: 51 percent / polyphosphoric acid / 0.67 h / 90 - 100 °C 4: N-bromoacetamide, AcOH / 3 h / Ambient temperature 5: 79 percent / MeONa / tetrahydrofuran / 4 h / Ambient temperature 6: N-bromosuccinimide, azoisobutyronitrile / CCl4 / 0.67 h / 60 - 70 °C 7: 62 percent / MeONa / tetrahydrofuran / 1) 0 deg C, 1 h, 2) rt, 3 h 8: 27 percent / KOH / H2O; 2-methyl-propan-2-ol / 168 h / Ambient temperature View Scheme

1: With acetic anhydride 1.5 h; Heating / reflux; 2: With hydrogenchloride; water 5 h; Heating / reflux; 3: With sodium hydroxide in water pH=7;