4,4'-Bis(Chloromethyl)- (CAS NO.: ), with other names as 2,2'-Bipyridine, 4,4'-bis(chloromethyl)-, could be produced through the following synthetic routes.

A. 4,4'-Bis[(trimethylsilyl)methyl]-2,2'-bipyridine . A 500-mL, two-necked, round-bottomed flask, equipped with a nitrogen inlet, magnetic stirrer, and rubber septum is charged with tetrahydrofuran (THF) (90 mL) and diisopropylamine (9.8 mL, 69.7 mmol). The reaction mixture is cooled to -78°C and a solution of butyllithium (n-BuLi) (1.7 M in hexanes, 36.0 mL, 61.4 mmol) is added. The solution is stirred at -78°C for 10 min, warmed to 0°C and stirred for 10 min, then cooled back to -78°C. A solution of (5.14 g, 27.9 mmol) in THF (130 mL), prepared in a 250-mL, two-necked, round-bottomed flask under a nitrogen atmosphere, is added via cannula to the cold lithium diisopropylamide (LDA) solution. The resulting maroon-black reaction mixture is stirred at -78°C for 1 hr, then chlorotrimethylsilane (TMSCl) (8.85 mL, 69.7 mmol) is rapidly added via syringe. After the solution becomes pale blue-green (≈10 sec after the TMSCl addition), the reaction is quenched by rapid addition of absolute ethanol (10 mL). (Note: the reaction should be quenched regardless of color change after a maximum of 15 seconds to avoid over silylation). The cold reaction mixture is poured into a separatory funnel (1 L) containing aqueous saturated sodium bicarbonate (NaHCO₃, ≈200 mL) and allowed to warm to ≈25°C. The product is extracted with dichloromethane (CH₂Cl₂, 3 × 300 mL); the combined organic fractions are shaken with brine (≈200 mL) and dried over sodium sulfate (Na₂SO₄). Filtration and concentration on a rotary evaporator affords 8.85 g (97%) of 4,4'-bis[(trimethylsilyl)methyl]-2,2'-bipyridine as a slightly off-white crystalline solid.

B. 4,4'-Bis(chloromethyl)-2,2'-bipyridine . Into a 500-mL, two-necked, round-bottomed flask equipped with a magnetic stirring bar are placed 5.22 g (15.9 mmol) of 4,4'-bis[(trimethylsilyl)methyl]-2,2'-bipyridine , 15.1 g (63.6 mmol) of hexachloroethane (Cl₃CCCl₃) and 9.65 g (63.6 mmol) of cesium fluoride (CsF) at 25°C under a nitrogen atmosphere. (260 mL) is added and the heterogeneous reaction mixture is stirred at 60°C for ≈3.5 hr (or until TLC indicates that all TMS starting material is consumed). After the mixture is cooled to 25°C, it is poured into a separatory funnel containing ethyl acetate (EtOAc) and water (H₂O, ≈100 mL each). The product is extracted with EtOAc (3 × 100 mL); the combined organic fractions are shaken with brine (≈200 mL) and dried over Na₂SO₄. Filtration and concentration on a rotary evaporator, followed by flash chromatography using deactivated silica gel (60% EtOAc: 40% hexanes), gives 3.67 g (91%) of the chloride as a white solid.