1: 95 percent / Dowex-WX4 / various solvent(s) / Heating 2: 85 percent / Na, MeOH / tetrahydrofuran / 1.5 h / Heating 3: 79 percent / aq. NaCl / dimethylsulfoxide / 4 h / Heating 4: 85 percent / Triton-X, 0.1 M aq. NaOH / 30 h / α-chymotrypsin 5: 1.) ethyl chloroformate, triethylamine, 2.) aq. NaN3 / 1.) acetone, from 0 deg C to 25 deg C, 55 min, 2.) acetone, 0 deg C, 2 h 6: toluene / 8 h / Heating 7: 6 N aq. HCl / 2 h / Heating View Scheme

1: With lithium aluminium tetrahydride in tetrahydrofuran 12 h; Inert atmosphereCooling with iceReflux; 2: With hydrogenchloride; water in tetrahydrofuran T=0 - 20°C; 0.5 h;

1: With benzotriazol-1-ol; 1-ethyl-(3-(3-dimethylamino)propyl)-carbodiimide hydrochloride in dichloromethane T=20°C; 0.5 h; 2: With sodium tetrahydroborate; cerium(III) chloride; water in tetrahydrofuran T=0°C; 0.5 h;

1.1: diphenyl phosphoryl azide; triethylamine / benzene / 2 h / |Inert atmosphere 2.1: bis-maleimidodiphenyl-methane acid / 3.5 h / 90 °C / |Inert atmosphere 3.1: N-bromosuccinmide / acetonitrile / 3.5 h / |Reflux; |Inert atmosphere 4.1: trichlorophosphate / 5 h / |Reflux; |Inert atmosphere 5.1: n-butyllithium / hexane; tetrahydrofuran / 0.75 h / 65 °C / |Inert atmosphere 5.2: 0.75 h / 65 °C / |Inert atmosphere 5.3: 0.5 h / -60 - -40 °C 6.1: diazomethyl-trimethyl-silane / hexane; acetonitrile / 14 h / 0 - 20 °C / |Inert atmosphere 7.1: potassium tert-butylate / dimethyl sulfoxide / 3.5 h / 10 - 20 °C / |Sonication; |Inert atmosphere 8.1: N-[(dimethylamino)-3-oxo-1H-1,2,3-triazolo[4,5-b]pyridin-1-yl-methylene]-N-methylmethanaminium hexafluorophosphate; N-ethyl-N,N-diisopropylamine / dichloromethane / 16 h / |Inert atmosphere 9.1: N-[(dimethylamino)-3-oxo-1H-1,2,3-triazolo[4,5-b]pyridin-1-yl-methylene]-N-methylmethanaminium hexafluorophosphate; N-ethyl-N,N-diisopropylamine / dichloromethane / 16 h / 20 °C / |Inert atmosphere View Scheme

1: lithium aluminium tetrahydride / tetrahydrofuran / 5 h / 80 °C / |Cooling with ice; |Inert atmosphere 2: pyridinium chlorochromate / dichloromethane / 4 h / 0 °C View Scheme

N-(chloromethylene)-N-methylmethanaminium chloride; sodium nitrite in neat (no solvent) T=100°C; P=1500.15 Torr; Microwave irradiation; Reagent/catalystTemperature;

1: 88 percent / H2 / 10percent Pd-C / tetrahydrofuran / 4 h / Ambient temperature 2: Et3N / tetrahydrofuran / 1.) -78 deg C, 15 min, 2.) 0 deg C, 45 min 3: n-BuLi / 1.) THF, hexane, -78 deg C, 20 min, 2.) -78 deg C, 15 min and room temp., 10 h 4: 1.) KHMDS, 2.) trisyl azide / 1.) THF, toluene, -78 deg C, 30 min, 2.) THF, -78 deg C, 2 min 5: H2, 5 N HCl / 10percent Pd-C / tetrahydrofuran; methanol / 8 h / 760 Torr / Ambient temperature 6: K2CO3 / tetrahydrofuran; H2O / Ambient temperature 7: 77 percent / aq. LiOH / tetrahydrofuran / 1 h / 0 °C View Scheme

sulfuric acid 5 h; Heating;

potassium carbonate in N,N-dimethyl-formamide 48 h; Inert atmosphere;

1: 78 percent / phosphoryl chloride, pyridine / 3 h / 60 °C 2: 77 percent / NaH / tetrahydrofuran / 2 h / Heating 3: 94 percent / TsOH / dimethylsulfoxide / 3 h / 100 °C View Scheme