2,6-Bis[1-[(2,6-diMethylphenyl)iMino]ethyl]pyridine

Synthesis

1. Synthesis of 2,6-diacetylpyridine bis(2,6-dimethylphenylimine) (2,6-Me2PDI) In a 250 mL round bottom flask, 4.0 g of 2,6-diacetylpyridine, 6.09 g (2.05 eq.) of 2,6-dimethylaniline and 100 mL of methanol were added sequentially. A catalytic amount of p-toluenesulfonic acid was then added, and the reaction mixture was placed in a reflux unit equipped with a Dean-Stark manifold to which potassium sulfate was pre-dosed. After refluxing the reaction mixture overnight, it was cooled to room temperature and the volume of methanol was concentrated to about half the starting volume by rotary evaporator. The concentrated mixture was cooled to -35 °C and the precipitated solid was collected by filtration to afford 4.5 g (50% yield) of the target product 2,6-Me2PDI.The filtrate can be further concentrated and cooled to obtain more product. The structure of the product was confirmed by 1H NMR (benzene-d6, 200 MHz): δ= 8.50 (d, 2H, pyridine interstitial hydrogen), 7.28 (t, 1H, pyridine para-hydrogen), 7.08 (d, 4H, aryl ring interstitial hydrogen), 6.99 (t, 2H, aryl ring para-hydrogen), 2.17 (s, 6H, methylene hydrogen), 2.05 (s, 12H, aryl ring methyl hydrogen).

References

[1] Dalton Transactions, 2017, vol. 46, # 23, p. 7408 - 7411
[2] Chemistry - A European Journal, 2014, vol. 20, # 16, p. 4754 - 4761
[3] Dalton Transactions, 2013, vol. 42, # 24, p. 8802 - 8807
[4] Journal of Molecular Catalysis A: Chemical, 2011, vol. 340, # 1-2, p. 83 - 88
[5] Patent: WO2011/6044, 2011, A2. Location in patent: Page/Page column 19-20