sodium tungstate; dihydrogen peroxide T=80 - 85°C; 10 h;

1: Pyridine-2,5-dicarboxylic acid N-oxide With thionyl chloride in dichloromethane; N,N-dimethyl-formamide T=65°C; 2 h; 2: methanol in dichloromethane; N,N-dimethyl-formamide T=0°C;

ethylene glycol

1.1: thionyl chloride / CH2Cl2; dimethylformamide / 2 h / 65 °C 1.2: 81.2 percent / CH2Cl2; dimethylformamide / 0 °C 2.1: Pd(PPh3)4 / toluene / 1 h / 20 °C 2.2: aq. Na2CO3 / toluene; ethanol / 8 h / 105 °C 2.3: 91 percent / HCl / diethyl ether / 20 °C View Scheme

1.1: thionyl chloride / CH2Cl2; dimethylformamide / 2 h / 65 °C 1.2: 81.2 percent / CH2Cl2; dimethylformamide / 0 °C 2.1: Pd(PPh3)4 / toluene / 1 h / 20 °C 2.2: aq. Na2CO3 / toluene; ethanol / 8 h / 105 °C 2.3: 91 percent / HCl / diethyl ether / 20 °C 3.1: 85 percent / Ca(BH4)2 / ethanol / 2 h / 20 °C 4.1: 92 percent / MnO2 / CH2Cl2 / 2 h / 20 °C View Scheme