1: 100 percent / H2 / 10percent Pd/C / methanol / 3 h / Ambient temperature 2: 1.) 2 M aq. NaOH / 1.) MeOH, 0 deg C, 6 h, 2.) MeOH, ether, RT, 30 min 3: 67 percent / EDCl / dimethylformamide / 1 h 4: dimethylformamide / 4 h / 55 °C View Scheme

1,1'-carbonyldiimidazole in tetrahydrofuran T=25°C; 3 h;

1.1: EDCI; DMAP / dimethylformamide; CH2Cl2 / 18 h / 25 °C 2.1: HCl / ethyl acetate / 2 h / 25 °C 3.1: 4.3 mg / EDCI; DMAP / dimethylformamide / 16 h / 25 °C 4.1: 98 percent / aq. LiOH / tetrahydrofuran; methanol / 8 h / 60 °C 5.1: EDCI; DMAP / dimethylformamide / 1 h / 25 °C 5.2: 68 percent / dimethylformamide / 13 h / 25 °C 6.1: HCl / ethyl acetate / 1 h / 25 °C 7.1: 3.8 mg / CDI / tetrahydrofuran / 3 h / 25 °C View Scheme

1.1: 4.3 mg / EDCI; DMAP / dimethylformamide / 16 h / 25 °C 2.1: 98 percent / aq. LiOH / tetrahydrofuran; methanol / 8 h / 60 °C 3.1: EDCI; DMAP / dimethylformamide / 1 h / 25 °C 3.2: 68 percent / dimethylformamide / 13 h / 25 °C 4.1: HCl / ethyl acetate / 1 h / 25 °C 5.1: 3.8 mg / CDI / tetrahydrofuran / 3 h / 25 °C View Scheme

1: H2 / Pd/C / methanol / 5 h / 20 °C / atmospheric pressure 2: ethanol / 48 h / Heating View Scheme

1.1: 4.3 mg / EDCI; DMAP / dimethylformamide / 16 h / 25 °C 2.1: 98 percent / aq. LiOH / tetrahydrofuran; methanol / 8 h / 60 °C 3.1: EDCI; DMAP / dimethylformamide / 1 h / 25 °C 3.2: 68 percent / dimethylformamide / 13 h / 25 °C 4.1: HCl / ethyl acetate / 1 h / 25 °C 5.1: 3.8 mg / CDI / tetrahydrofuran / 3 h / 25 °C View Scheme

1.1: HCl / ethyl acetate / 2 h / 25 °C 2.1: 4.3 mg / EDCI; DMAP / dimethylformamide / 16 h / 25 °C 3.1: 98 percent / aq. LiOH / tetrahydrofuran; methanol / 8 h / 60 °C 4.1: EDCI; DMAP / dimethylformamide / 1 h / 25 °C 4.2: 68 percent / dimethylformamide / 13 h / 25 °C 5.1: HCl / ethyl acetate / 1 h / 25 °C 6.1: 3.8 mg / CDI / tetrahydrofuran / 3 h / 25 °C View Scheme

1.1: EDCI; DMAP / dimethylformamide / 1 h / 25 °C 1.2: 68 percent / dimethylformamide / 13 h / 25 °C 2.1: HCl / ethyl acetate / 1 h / 25 °C 3.1: 3.8 mg / CDI / tetrahydrofuran / 3 h / 25 °C View Scheme

1.1: 98 percent / aq. LiOH / tetrahydrofuran; methanol / 8 h / 60 °C 2.1: EDCI; DMAP / dimethylformamide / 1 h / 25 °C 2.2: 68 percent / dimethylformamide / 13 h / 25 °C 3.1: HCl / ethyl acetate / 1 h / 25 °C 4.1: 3.8 mg / CDI / tetrahydrofuran / 3 h / 25 °C View Scheme

1: HCl / ethyl acetate / 1 h / 25 °C 2: 3.8 mg / CDI / tetrahydrofuran / 3 h / 25 °C View Scheme