[Synthesis]
Diisopropylamine (28.0 mL, 0.160 mol, 2.66 eq.) was dissolved in anhydrous tetrahydrofuran (THF, 60 mL) under argon protection. The reaction system was cooled to 0 °C, n-butyllithium (107.0 mL, 0.160 mol, 2.66 eq.) was added slowly dropwise and stirred at this temperature for 1 hour. Subsequently, anhydrous THF (300 mL) solution of 4,4'-dimethyl-2,2'-bipyridine (11.0 g, 0.060 mol, 1 eq.) was added drop-wise, the reaction mixture took on an orange color, and stirring was continued for 3 hours. Keeping the reaction system at 0 °C, a solution of anhydrous THF (20 mL) of 1-bromooctane (28.0 mL, 0.160 mol, 2.66 equiv) was added. The reaction mixture was gradually warmed to room temperature and stirred continuously for 12 hours. Upon completion of the reaction, the reaction was first quenched with deionized water (20 mL) and then the mixture was poured into an ice-water mixture and extracted with diethyl ether. The resulting yellow oily product was purified by recrystallization from hexane and subsequently dissolved in dichloromethane (DCM), washed with dilute sodium hydroxide solution, dried over magnesium sulfate, filtered and the solvent was removed under reduced pressure. The final product was dried under high vacuum to afford 4,4'-dinonyl-2,2'-bipyridine (11.02 g, 0.027 mol, 45% yield). The structure of the product was confirmed by 1H NMR (500 MHz, DMSO) and HRMS (ESI): 1H NMR δ 8.85 (s, 1H), 8.83 (s, 1H), 7.28 (s, 1H), 7.27 (s, 1H), 2.68 (t, J = 7.6 Hz, 4H), 1.62 (p, J = 8.2, 6.9 Hz, 4H). 1.32-1.11 (m, 24H), 0.83 (t, J = 6.5 Hz, 6H); HRMS (ESI) m/z: [M + H]+ Calculated value 409.358, measured value 409.3581. |