2,2'-Dibromobiphenyl is used to produce 5,5-dimethyl-5H-dibenzosilole at the temperature of -78 - 20°C. It will need reagent n-BuLi and solvents diethyl ether, hexane.
2,2'-Dibromobiphenyl is a polybrominated biphenyl. Polybrominated biphenyls (PBBs) are a group of 209 synthetic organic compounds with 1-10 bromine atoms attached to biphenyl. They can be used as flame retardants and may be added to the plastics used to make products like computer monitors, televisions, textiles, and plastic foams, making them difficult to burn. However, PBBs are banned or restricted in most areas due to their toxicity and persistence in the environment.
Pd(PPh3)4 (18.5 mg, 0.016 mmol, 4 mol) and indium (45.9 mg, 0.4 mmol, 1 equivalent) were added to a solution of 2-bromoiodobenzene (0.4 mmol) in DMF (2 ml). The resulting mixture was heated at 100°C at room temperature. The reaction process was monitored by thin-layer chromatography, with ethyl acetate and n-hexane (1:4 or 1:10, depending on the polarity of the substrate) as the developing solvent. After 34 hours of reaction, the raw materials reacted completely, and a saturated sodium bicarbonate solution (4 ml) was added to quench the reaction, and the reaction solution was extracted with ethyl acetate (10 ml). The ethyl acetate layer was washed twice with water (4 ml) and then once with brine (4 ml). The organic phase was dried over MgSO4, filtered and concentrated under reduced pressure. The concentrate was chromatographed on silica gel using n-hexane or a solution of ethyl acetate and n-hexane for purification and separation to obtain the target product 2,2'-Dibromobiphenyl.
