1: tert-butyl (dimethoxyphosphoryl)acetate With sodium hydride in tetrahydrofuran T=0°C; 1 h; 2: pyridine-4-carbaldehyde in tetrahydrofuran T=0 - 20°C; 19 h; 3: With hydrogen; palladium 10 on activated carbon in etanol 6 h;

ammonium formate; palladium 10 on activated carbon in ethanol; water 3 h; Heating / reflux;