1: H2 / platinum oxide / methanol / 50 h / Ambient temperature 2: DCC / acetonitrile / 3 h / 60 °C 3: 56 percent / triethylamine / dimethylformamide / 24 h / Ambient temperature 4: 43 percent / aqueous sodium hydroxide / tetrahydrofuran; methanol / 8 h / Ambient temperature 5: 62 percent / triethylamine / dimethylformamide / 24 h / Ambient temperature 6: 65.1 percent / potassium acetate / dimethylformamide / 1 h / 40 °C View Scheme

Multi-step reaction with 4 steps 1: H2 / platinum oxide / methanol / 50 h / Ambient temperature2: DCC / acetonitrile / 3 h / 60 °C3: 56 percent / triethylamine / dimethylformamide / 24 h / Ambient temperature4: 43 percent / aqueous sodium hydroxide / tetrahydrofuran; methanol / 8 h / Ambient temperature