1: monoethyl tert-butyl malonate With sodium hydride in tetrahydrofuran T=20°C; 0.25 h; 2: 2-chloro-5-nitro-pyridine in tetrahydrofuran T=20°C; 10 h; 3: With trifluoroacetic acid in dichloromethane T=20°C; 2 h;

water; sodium chloride in dimethyl sulfoxide T=120°C; 2 h;

1: trichlorophosphate; phosphorus pentachloride / 16 h / 60 °C 2: potassium carbonate / N,N-dimethyl-formamide / 16 h / 70 °C 3: sodium chloride; water / dimethyl sulfoxide / 2 h / 120 °C View Scheme