1: With diphenyl phosphoryl azide; triethylamine in dichloromethane; toluene T=60 - 70°C; 1.5 h; 2: With hydrogenchloride; water in dichloromethane; toluene 2 h; Heating / reflux;

sodium in toluene 4 h; Heating;

1: 85 percent / Dabco / 24 h / Heating 2: 90 percent / 10percent aq. NaOH / 24 h / Heating 3: (PhO)2P(=O)N3, Et3N / 45 °C 4: 2.) 6N aq. HCl / 1.) toluene, 80 deg C, 2.) reflux View Scheme

1: 90 percent / 10percent aq. NaOH / 24 h / Heating 2: (PhO)2P(=O)N3, Et3N / 45 °C 3: 2.) 6N aq. HCl / 1.) toluene, 80 deg C, 2.) reflux View Scheme

3,5-bis(ethoxycarbonyl)-2,6-diethylpyridine 1-oxide; Me4tBuXPhosAuNTf2 in 1,2-dichloro-ethane T=20°C; regioselective reaction;

1: 77 percent / cc. sulfuric acid / 12 h / Heating 2: sodium / toluene / 4 h / Heating View Scheme

1: 40 percent / diethyl ether / 0 °C 2: 92 percent / potassium carbonate, potassium iodide / 4 h / Heating 3: 1.) potassium metabisulfite / 1.) 50 deg C, water 2.) water, ether, 5 deg C, 6 h 4: stannous chloride dihydrate, cc. hydrogen chloride, acetic acid, hydrogen iodide / 3 h / Heating 5: 77 percent / cc. sulfuric acid / 12 h / Heating 6: sodium / toluene / 4 h / Heating View Scheme

1: 76 percent / potassium carbonate / 2 h / Heating 2: 1.) morpholine, sulfur 2.) 10 percent aq. sodium hydroxide / 1.) 160 deg C, 4 h 2.) reflux, 4 h 3: 80 percent / sulfuric acid / Heating 4: potassium carbonate / 6 h / Heating 5: sodium / toluene / 4 h / Heating View Scheme

1: 1.) morpholine, sulfur 2.) 10 percent aq. sodium hydroxide / 1.) 160 deg C, 4 h 2.) reflux, 4 h 2: 80 percent / sulfuric acid / Heating 3: potassium carbonate / 6 h / Heating 4: sodium / toluene / 4 h / Heating View Scheme

1: 80 percent / sulfuric acid / Heating 2: potassium carbonate / 6 h / Heating 3: sodium / toluene / 4 h / Heating View Scheme