1: 1,1-dimethylethylhydrazine hydrochloride With sodium hydroxide in water; toluene T=20°C; 2: 3,4-dichloro-5-hydroxyfuran-2(5H)-one in water; toluene T=20°C; 3: With acetic acid in water; toluene T=45 - 50°C; 18 h;

in methanol

hydrazine hydrate in ethanol T=85°C; 6 h;

1.1: caesium carbonate / N,N-dimethyl-formamide / 4 h / 65 °C 2.1: phosphorus tribromide / dichloromethane / 1 h / 25 °C 3.1: potassium tert-butylate / 60 °C 3.2: 16.5 h / 60 °C 4.1: 4-(N,N-dimethlyamino)pyridine; triethylamine / dichloromethane / 22 h / 20 °C 5.1: TEAHCO3; tetraethyl ammonium [18]F-fluoride / acetonitrile / 0.17 h / 90 °C View Scheme

potassium hydroxide in ethylene glycol T=130°C; 5 h;

sodium hydrogensulfide in ethanol T=0°C; 2 h;

hydrogenchloride; sodium hydrogensulfide in water