1,4-dibromobenzene (0.980 g, 4.15 mmol) and pinacol ester of 4-aminobenzeneboronic acid (2.0 g, 9.13 mmol) were catalyzed by Pd(PPh3)4 (0.3 g, 0.415 mmol) with the addition of K2CO3 (8.6 g, 62.3 mmol), water (10 mL) and toluene (10 mL) in a 50 mL Schlenk flask equipped with a magnetic stirrer. The mixture was rapidly frozen by liquid nitrogen, evacuated to 50 mT, and thawed under static vacuum; this freeze-evacuate-thaw cycle was repeated three times. Subsequently, the flask was backfilled with N2 and a water-cooled condenser, red septum and bubbler were attached to maintain a positive N2 flow under N2 atmosphere. The reaction mixture was heated to 120 °C under N2 protection for 24 h. The progress of the reaction was monitored by TLC. Upon completion of the reaction, it was cooled to room temperature, quenched with water (5 mL) and extracted with EtOAc (3 x 10 mL). The organic phases were combined, washed sequentially with water (3 × 10 mL) and brine (3 × 10 mL), dried over anhydrous Na2SO4 and filtered through diatomaceous earth. The solvent was concentrated under reduced pressure, rotary evaporated at 40 °C, and subsequently purified by silica gel column chromatography (eluent: 35% EtOAc in hexane solution) to afford the white solid product 4,4'-diaminotriphenylene in a yield of 0.560 g (52%). The product was analyzed by 1H NMR (400 MHz, DMSO-d6) δ 7.53 (s, 1H), 7.39-7.35 (d, 1H), 6.66-6.62 (d, 1H), 5.20 (s, 1H); 13C NMR (100 MHz, DMSO) δ 148.18, 137.93, 127.11, 126.82, 125.55, 114.22, 99.51, 39.52; HRMS (ESI-TOF) m/z calculated value C18H16N2 [M+H]+: 261.1393, measured value 261.1355.
