1: 77 percent / dicyclohexylcarbodi-imide, 1-hydroxybenzotriazole / dimethylformamide 2: 88 percent / sodium hydroxide / dioxane; H2O / 1 h / 0 °C 3: trifluoroacetic acid 4: hydrogen / 10percent palladium-charcoal / aq. acetic acid / 15 h View Scheme