1: 8-aza-spiro[4.5]decane-7,9-dione With potassium hydroxide in ethanol T=20°C; 2 h; 2: 1,4-dibromo-butane in acetone T=50°C; Gabriel reaction; 8 h; 3: 1-(pyrimidin-2-yl)-piperazine With potassium carbonate in acetone; butan-1-ol 15 h; Reflux;

sodium tris(acetoxy)borohydride; acetic acid in dichloromethane T=20°C; 0.333333 h;

1: hydrogenchloride; water / dichloromethane / 2.5 h / 20 °C 2: sodium tris(acetoxy)borohydride; acetic acid / dichloromethane / 0.33 h / 20 °C View Scheme

1: tetrabutylammomium bromide; potassium carbonate / dimethyl sulfoxide / 4 h / 80 °C 2: hydrogenchloride; water / dichloromethane / 2.5 h / 20 °C 3: sodium tris(acetoxy)borohydride; acetic acid / dichloromethane / 0.33 h / 20 °C View Scheme