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Example 17- Synthesis of 2,6-dibromonaphthalene-1,5-diol: 1,5-dihydroxynaphthalene (115.2 g) was suspended in acetonitrile (800 mL) under nitrogen protection. Subsequently, N,N-dimethylformamide (DMF) solution of N-bromosuccinimide (NBS) (400 mL containing 254 g of NBS) was added slowly and dropwise. The reaction mixture was stirred at room temperature and the reaction progress was monitored by gas chromatography-mass spectrometry (GC-MS). Upon completion of the reaction, the reaction was quenched by the addition of water. The resulting precipitate was collected by filtration and washed with plenty of water to give 2,6-dibromonaphthalene-1,5-diol in 80% yield. Mass spectrometry (electrospray ionization, ESI) analysis resulted in a calculated value (C10H6Br2O2) of 317.9614 and a measured value of 317.9.