1: 2,4-Dihydroxy-3-nitropyridine With sodium hydride in N,N-dimethyl-formamide T=0°C; 0.25 h; 2: ethyl iodide in N,N-dimethyl-formamide T=0 - 55°C; 17 h;

trichlorophosphate 1 h; Heating / reflux;