1.1: potassium carbonate / acetone / 0 - 20 °C / Inert atmosphere 2.1: iron / acetic acid / 2.5 h / 70 - 100 °C / Inert atmosphere 3.1: sodium hydride / isobutyramide; mineral oil / -10 - 20 °C / Inert atmosphere 4.1: hydrogenchloride / ethanol; water / 48 h / Inert atmosphere; Reflux 5.1: O-(1H-benzotriazol-1-yl)-N,N,N',N'-tetramethyluronium hexafluorophosphate; diisopropylamine / N,N-dimethyl-formamide / 0.5 h / 20 °C / Inert atmosphere 5.2: 3 h / 20 °C / Inert atmosphere View Scheme

sodium acetate; sodium tris(acetoxy)borohydride in dichloromethane T=0 - 20°C; Inert atmosphere;

1: (R)-methyl 2-(cyclopentylamino)butanoate With sodium hydrogencarbonate in cyclohexane T=20 - 30°C; 0.5 h; 2: 2,4-Dichloro-5-nitro-pyrimidine in cyclohexane T=60°C; 12 h; Inert atmosphere;

1: potassium carbonate / acetone / 16 h / 0 °C 2: hydrogen; acetic acid / Raney Ni / 50 °C View Scheme

1: potassium carbonate / acetone / 0 - 20 °C / Inert atmosphere 2: iron / acetic acid / 2.5 h / 70 - 100 °C / Inert atmosphere 3: sodium hydride / isobutyramide; mineral oil / -10 - 20 °C / Inert atmosphere 4: hydrogenchloride / ethanol; water / 48 h / Inert atmosphere; Reflux View Scheme