1: MnO2 / diethyl ether; H2O 2: Br2 / Fe / CH2Cl2 3: 0.83 g / 2,6-pyridinedicarboxylic acid; ammonium cerium(IV) nitrate / H2O; acetonitrile / 20 °C 4: 100 percent / CH2Cl2 / 40 h 5: NaOMe / toluene / 2 h / 0 - 20 °C 6: 96 percent / maleic anhydride / toluene / 4 h / Heating View Scheme

1: With manganese(IV) oxide in diethyl ether T=18 - 25°C; 18 h; 2: With hydrogenchloride in tetrahydrofuran T=20 - 30°C; 0.5 h;

1.1: MnO2 / diethyl ether; H2O 2.1: Br2 / Fe / CH2Cl2 3.1: 0.83 g / 2,6-pyridinedicarboxylic acid; ammonium cerium(IV) nitrate / H2O; acetonitrile / 20 °C 4.1: 100 percent / CH2Cl2 / 40 h 5.1: NaOMe / toluene / 2 h / 0 - 20 °C 6.1: 96 percent / maleic anhydride / toluene / 4 h / Heating 7.1: LDA; tributyltin hydride / tetrahydrofuran; hexane / 2 h 7.2: Ag2O / BF3*OEt2 / CH2Cl2 / 2 h View Scheme

lithium diisopropyl amide in tetrahydrofuran; hexane T=-10 - 10°C; 1.08333 h;

1.1: MnO2 / diethyl ether / 18 h / 18 - 25 °C 1.2: 90 percent / aq. HCl / tetrahydrofuran / 0.5 h / 20 - 30 °C 2.1: 68 percent / potassium nitrosodisulfonate / aq. phosphate buffer; diethyl ether / 18 h View Scheme