oxygen; magnesium sulfate; silver(l) oxide in tetrahydrofuran T=20°C; 0.25 h;

pyridine-2,6-dicarboxylic acid; ammonium cerium(VI) nitrate in water; acetonitrile

1.1: 91 percent / KF; HCl; water / methanol / 2 h / Heating 2.1: 75 percent / Red-Al / toluene / 3 h / Heating 3.1: H2SO4; NaNO2 / H2O / 0.08 h 3.2: 77 percent / CuSO4*5H2O; Cu2O / H2O / 0.75 h 4.1: 84 percent / iron; bromine / CH2Cl2 / 20 °C 5.1: 51 percent / 2,6-pyridinedicarboxylic acid; ammonium cerium(VI) nitrate / acetonitrile; H2O View Scheme

1: 84 percent / iron; bromine / CH2Cl2 / 20 °C 2: 51 percent / 2,6-pyridinedicarboxylic acid; ammonium cerium(VI) nitrate / acetonitrile; H2O View Scheme

1.1: 75 percent / Red-Al / toluene / 3 h / Heating 2.1: H2SO4; NaNO2 / H2O / 0.08 h 2.2: 77 percent / CuSO4*5H2O; Cu2O / H2O / 0.75 h 3.1: 84 percent / iron; bromine / CH2Cl2 / 20 °C 4.1: 51 percent / 2,6-pyridinedicarboxylic acid; ammonium cerium(VI) nitrate / acetonitrile; H2O View Scheme

1.1: 3.85 g / Red-Al / toluene / 3 h / Heating 2.1: 0.65 g / trifluoroacetic acid / hexane / 5 h / Heating 3.1: H2SO4; NaNO2 / H2O / 0.08 h 3.2: 77 percent / CuSO4*5H2O; Cu2O / H2O / 0.75 h 4.1: 84 percent / iron; bromine / CH2Cl2 / 20 °C 5.1: 51 percent / 2,6-pyridinedicarboxylic acid; ammonium cerium(VI) nitrate / acetonitrile; H2O View Scheme

1.1: H2SO4; NaNO2 / H2O / 0.08 h 1.2: 77 percent / CuSO4*5H2O; Cu2O / H2O / 0.75 h 2.1: 84 percent / iron; bromine / CH2Cl2 / 20 °C 3.1: 51 percent / 2,6-pyridinedicarboxylic acid; ammonium cerium(VI) nitrate / acetonitrile; H2O View Scheme

1.1: 0.65 g / trifluoroacetic acid / hexane / 5 h / Heating 2.1: H2SO4; NaNO2 / H2O / 0.08 h 2.2: 77 percent / CuSO4*5H2O; Cu2O / H2O / 0.75 h 3.1: 84 percent / iron; bromine / CH2Cl2 / 20 °C 4.1: 51 percent / 2,6-pyridinedicarboxylic acid; ammonium cerium(VI) nitrate / acetonitrile; H2O View Scheme

(i) aq. HBr, (ii) aq. K2Cr2O7, H2SO4; Multistep reaction;