1.1: 2,4,6-trichlorobenzoyl chloride; Et3N / tetrahydrofuran / 0.5 h / 0 °C 1.2: 74 percent / DMAP / tetrahydrofuran; toluene / 3 h 2.1: 82 percent / Zn; NH4Cl / methanol / 0.08 h / 20 °C 3.1: 38 percent / HF*pyridine / 168 h / 35 - 40 °C View Scheme