1: 83 percent / 4-dimethylaminopyridine, dicyclohexylcarbodiimide / CH2Cl2 / 1.) 0 deg C, 5 min, 2.) r.t., 3 h 2: 81 percent / aq. NaOH / methanol / 2.5 h / Ambient temperature 3: 67 percent / 2-isobutyloxy-1-isobutyloxycarbonyl-1,2-dihydroquinoline / tetrahydrofuran / 1.) r.t., 2.) reflux 4: 76 percent / CF3COOH / CH2Cl2 / 1.5 h / Ambient temperature 5: 30 percent / H2 / 10percent Pd-C / methanol / 20 °C View Scheme

1: 83 percent / 4-dimethylaminopyridine, dicyclohexylcarbodiimide / CH2Cl2 / 1.) 0 deg C, 5 min, 2.) r.t., 3 h 2: 81 percent / aq. NaOH / methanol / 2.5 h / Ambient temperature View Scheme