1: With sodium hydroxide; threo-1,4-dimercapto-2,3-butanediol in methanol; water T=1 - 20°C; pH=6 - 2; 1.83333 h; 2: With hydrogenchloride in methanol; water T=20 - 40°C; pH=6 - 2; 1.5 h; Heating / reflux;

sodium hydroxide in methanol 5.5 h;

1: 92 percent / H2 / Pd(OH)2 / methanol / 4 h 2: 93 percent / 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride / CH2Cl2 / 2.5 h 3: 93 percent / CF3CO2H / CH2Cl2 / 5 h / 25 °C 4: 92 percent / DL-dithiothreitol; NaOH / methanol; H2O / 1.5 h / 1 - 20 °C View Scheme

1: 95 percent / Cs2CO3 / dimethylformamide / 2 h / Ambient temperature 2: 1.) (COCl)2, DMSO, 2.) Et3N / 1.) CH2Cl2, -78 deg C, 15 min, 2.) CH2Cl2, -78 deg C, 5 min 3: CH2Cl2 / 0.5 h 4: 1.) (COCl)2, DMSO, 2.) Et3N / 1.) CH2Cl2, -78 deg C, 15 min, 2.) CH2Cl2, from -78 deg C to 0 deg C 5: 1.) TiCl4 / 1.) Et2O, from -78 deg C to -35 deg C, 2.) Et2O, 0 deg C, 4 h 6: 81 percent / azidotrimethylsilane, BF3*OEt2 / CH2Cl2 / 120 h / Ambient temperature 7: H2 / 10 percent Pd/C / dimethylformamide / 24 h 8: HOBT, EDAC*HCl / dimethylformamide / 3.5 h / Ambient temperature 9: hydrazine hydrate / methanol; CH2Cl2 / 48 h / Ambient temperature 10: CH2Cl2 / 1.5 h / Ambient temperature 11: lithium bis(trimethylsilyl)amide / tetrahydrofuran / 30 h / Ambient temperature 12: TFA / CH2Cl2 / 1 h / Ambient temperature 13: 92 percent / EDAC / CH2Cl2 / 2 h / 0 °C 14: 95 percent / 1.0 N NaOH / methanol / 5.5 h View Scheme

1: CH2Cl2 / 0.5 h 2: 1.) (COCl)2, DMSO, 2.) Et3N / 1.) CH2Cl2, -78 deg C, 15 min, 2.) CH2Cl2, from -78 deg C to 0 deg C 3: 1.) TiCl4 / 1.) Et2O, from -78 deg C to -35 deg C, 2.) Et2O, 0 deg C, 4 h 4: 81 percent / azidotrimethylsilane, BF3*OEt2 / CH2Cl2 / 120 h / Ambient temperature 5: H2 / 10 percent Pd/C / dimethylformamide / 24 h 6: HOBT, EDAC*HCl / dimethylformamide / 3.5 h / Ambient temperature 7: hydrazine hydrate / methanol; CH2Cl2 / 48 h / Ambient temperature 8: CH2Cl2 / 1.5 h / Ambient temperature 9: lithium bis(trimethylsilyl)amide / tetrahydrofuran / 30 h / Ambient temperature 10: TFA / CH2Cl2 / 1 h / Ambient temperature 11: 92 percent / EDAC / CH2Cl2 / 2 h / 0 °C 12: 95 percent / 1.0 N NaOH / methanol / 5.5 h View Scheme

1: 1.) (COCl)2, DMSO, 2.) Et3N / 1.) CH2Cl2, -78 deg C, 15 min, 2.) CH2Cl2, -78 deg C, 5 min 2: CH2Cl2 / 0.5 h 3: 1.) (COCl)2, DMSO, 2.) Et3N / 1.) CH2Cl2, -78 deg C, 15 min, 2.) CH2Cl2, from -78 deg C to 0 deg C 4: 1.) TiCl4 / 1.) Et2O, from -78 deg C to -35 deg C, 2.) Et2O, 0 deg C, 4 h 5: 81 percent / azidotrimethylsilane, BF3*OEt2 / CH2Cl2 / 120 h / Ambient temperature 6: H2 / 10 percent Pd/C / dimethylformamide / 24 h 7: HOBT, EDAC*HCl / dimethylformamide / 3.5 h / Ambient temperature 8: hydrazine hydrate / methanol; CH2Cl2 / 48 h / Ambient temperature 9: CH2Cl2 / 1.5 h / Ambient temperature 10: lithium bis(trimethylsilyl)amide / tetrahydrofuran / 30 h / Ambient temperature 11: TFA / CH2Cl2 / 1 h / Ambient temperature 12: 92 percent / EDAC / CH2Cl2 / 2 h / 0 °C 13: 95 percent / 1.0 N NaOH / methanol / 5.5 h View Scheme

1: 1.) (COCl)2, DMSO, 2.) Et3N / 1.) CH2Cl2, -78 deg C, 15 min, 2.) CH2Cl2, from -78 deg C to 0 deg C 2: 1.) TiCl4 / 1.) Et2O, from -78 deg C to -35 deg C, 2.) Et2O, 0 deg C, 4 h 3: 81 percent / azidotrimethylsilane, BF3*OEt2 / CH2Cl2 / 120 h / Ambient temperature 4: H2 / 10 percent Pd/C / dimethylformamide / 24 h 5: HOBT, EDAC*HCl / dimethylformamide / 3.5 h / Ambient temperature 6: hydrazine hydrate / methanol; CH2Cl2 / 48 h / Ambient temperature 7: CH2Cl2 / 1.5 h / Ambient temperature 8: lithium bis(trimethylsilyl)amide / tetrahydrofuran / 30 h / Ambient temperature 9: TFA / CH2Cl2 / 1 h / Ambient temperature 10: 92 percent / EDAC / CH2Cl2 / 2 h / 0 °C 11: 95 percent / 1.0 N NaOH / methanol / 5.5 h View Scheme

1: 1.) TiCl4 / 1.) Et2O, from -78 deg C to -35 deg C, 2.) Et2O, 0 deg C, 4 h 2: 81 percent / azidotrimethylsilane, BF3*OEt2 / CH2Cl2 / 120 h / Ambient temperature 3: H2 / 10 percent Pd/C / dimethylformamide / 24 h 4: HOBT, EDAC*HCl / dimethylformamide / 3.5 h / Ambient temperature 5: hydrazine hydrate / methanol; CH2Cl2 / 48 h / Ambient temperature 6: CH2Cl2 / 1.5 h / Ambient temperature 7: lithium bis(trimethylsilyl)amide / tetrahydrofuran / 30 h / Ambient temperature 8: TFA / CH2Cl2 / 1 h / Ambient temperature 9: 92 percent / EDAC / CH2Cl2 / 2 h / 0 °C 10: 95 percent / 1.0 N NaOH / methanol / 5.5 h View Scheme

1: 81 percent / azidotrimethylsilane, BF3*OEt2 / CH2Cl2 / 120 h / Ambient temperature 2: H2 / 10 percent Pd/C / dimethylformamide / 24 h 3: HOBT, EDAC*HCl / dimethylformamide / 3.5 h / Ambient temperature 4: hydrazine hydrate / methanol; CH2Cl2 / 48 h / Ambient temperature 5: CH2Cl2 / 1.5 h / Ambient temperature 6: lithium bis(trimethylsilyl)amide / tetrahydrofuran / 30 h / Ambient temperature 7: TFA / CH2Cl2 / 1 h / Ambient temperature 8: 92 percent / EDAC / CH2Cl2 / 2 h / 0 °C 9: 95 percent / 1.0 N NaOH / methanol / 5.5 h View Scheme

1: H2 / 10 percent Pd/C / dimethylformamide / 24 h 2: HOBT, EDAC*HCl / dimethylformamide / 3.5 h / Ambient temperature 3: hydrazine hydrate / methanol; CH2Cl2 / 48 h / Ambient temperature 4: CH2Cl2 / 1.5 h / Ambient temperature 5: lithium bis(trimethylsilyl)amide / tetrahydrofuran / 30 h / Ambient temperature 6: TFA / CH2Cl2 / 1 h / Ambient temperature 7: 92 percent / EDAC / CH2Cl2 / 2 h / 0 °C 8: 95 percent / 1.0 N NaOH / methanol / 5.5 h View Scheme