1: piperidine-1,3-dicarboxylic acid 1-tert-butyl ester-3-methyl ester With sodium hexamethyldisilazane in tetrahydrofuran T=-78°C; 0.5 h; 2: methyl iodide in tetrahydrofuran T=20°C;

lithium hexamethyldisilazane in tetrahydrofuran T=-78 - 25°C; 4 h;

sodium hydroxide; ethanol T=25 - 70°C; 3 h;

1: With lithium aluminium tetrahydride in tetrahydrofuran T=0 - 20°C; 2: With water; ammonium chloride in tetrahydrofuran T=20°C;