4,4'-Di-tert-butyl-2,2'-bipyridine

1. Ligand for the iridium-catalyzed borylation of arenes
2. Ligand for the iridium-catalyzed synthesis of arylboronic acids and aryl trifluoroborates
3. Ligand for the nickel-catalyzed hydroxycarboxylation of 1,2-dienes by reaction carbon dioxide and oxygen
4. Ligand for the iridium-catalyzed meta borylation followed by halogenation of 1,3-disubstituted arenes
5. Ligand for the iridium-catalyzed silyl-directed ortho-borylation of arenes
6. Ligand for the iridium-catalyzed silane borylation followed by aryl borylation
7. Ligand for the iridium-catalyzed microwave-accelerated borylation of aromatic C-H bonds
8. Ligand for the iridium-catalyzed silyl-directed borylation of indoles
9. Ligand for the nickel-catalyzed synthesis of functionalized dialkyl ketones from carboxylic acids and alkyl halides
10. Ligand for the iron-catalyzed arylation of heterocycles 

3978-81-2

72914-19-3

In this embodiment, the synthesis of 4,4'-di-tert-butyl-2,2'-bipyridine from 4-tert-butylpyridine was investigated. This was done as follows: 4-tert-butylpyridine (0.5 mmol) was reacted with SD (1 to 2 molar equivalents) in THF (2 to 4 mL) at a reaction temperature of 50°C for a reaction time of 1 to 24 hours. Upon completion of the reaction, the reaction products were isolated and purified according to the method of Example 1 to obtain 4,4'-di-tert-butyl-2,2'-bipyridine (target product), 4-tert-butyl-1,4-dihydropyridine (byproduct 1), and 4,4',4''-tri-tert-butyl-2,2':6',2''-tripyridine (byproduct 3), and the respective yields were calculated. Also, the recovery of unreacted 4-tert-butylpyridine was calculated. The experimental results showed that the highest yield of 4,4'-di-tert-butyl-2,2'-bipyridine was achieved under the optimal conditions (0.5 mmol of 4-tert-butylpyridine reacted with 1 molar equivalent of SD in 4 mL of THF at 50 °C for 6 h) and no by-products were generated. In addition, the use of 2 molar equivalents of SD resulted in a lower yield and material balance. Comparison with Example 1 shows that decreasing the concentration of 4-tert-butylpyridine and SD relative to THF contributes to higher yields.