1: 87 percent / triethylamine, N-hydroxybenzotriazole / dimethylformamide / 16 h 2: 93 percent / 4M HBr / acetic acid / 1 h 3: 82 percent / triethylamine / CH2Cl2 / 0.5 h 4: 76 percent / 1M KOH / methanol / 5 h View Scheme