sodium hydroxide 1) methanol, 3 h, room temperature, 2) 15 min, 130 deg C; Yield given. Multistep reaction;

1: NaOH / tetrahydrofuran; methanol / 2 h / 15 °C 2: 1) 0.5N NaOH, sodium dithionite; 2) air / 1) THF/MeOH, 30 min; 2) 15 min View Scheme

1: 82 percent / -100 °C 2: NaOH / tetrahydrofuran; methanol / 2 h / 15 °C 3: 1) 0.5N NaOH, sodium dithionite; 2) air / 1) THF/MeOH, 30 min; 2) 15 min View Scheme

1: NaOH / tetrahydrofuran; methanol / 2 h / 15 °C 2: 1) 0.5N NaOH, sodium dithionite; 2) air / 1) THF/MeOH, 30 min; 2) 15 min 3: 82 percent / -100 °C 4: NaOH / tetrahydrofuran; methanol / 2 h / 15 °C 5: 1) 0.5N NaOH, sodium dithionite; 2) air / 1) THF/MeOH, 30 min; 2) 15 min View Scheme

1: 1) NaOC2H5 / 1) ethanol, 2) DMF, 1 h, 10 deg C 2: 1) 1 N NaOH / 1) methanol, 3 h, room temperature, 2) 15 min, 130 deg C View Scheme

hydrogen bromide in acetic acid 12 h; Heating;