Background and overview of synthesis methods and application examples of 4,4′-di-tert-butyl-2,2′-dipyridine
4,4′-di-tert-butyl-2,2′-dipyridine is an organic intermediate that can be synthesized from 4-(tert-butyl)-2-(tert-butyldimethylsilyl)pyridine and 2-bromo-4-(tert-butyl)pyridine were prepared by Hiyama-Denmark cross-coupling reaction.
Synthetic methods and application examples of 4,4′-di-tert-butyl-2,2′-dipyridine
General Procedure A: To a 10 mL vial equipped with a Teflon septa and a magnetic stir bar, add the corresponding heterocycle (0.5 mmol, 1.0 equiv), the corresponding silane (2.5 mmol, 5.0 equiv), Na 2S2O8 (1.0mmol, 2.0) ) and Ir (ppy) 2 (dtbpy) PF 6 (0.005 mmol, 0.01 equiv). Seal the vial and place it in the atmosphere, then add DMSO/DCE (1:1) (5 mL, 0.1 M). Place the reaction mass between 2 × 23 W fluorescent lamps (approximately 5 cm per lamp) and illuminate for 24 h. The reaction mixture was diluted with saturated NaHCO3 aqueous solution, extracted with ethyl acetate (3×20 mL), the combined organic extracts were washed with brine (30 mL), and filtered with anhydrous Na2SO4 was dried and concentrated in vacuo. The crude product was purified by silica gel flash chromatography using the specified solvent system to give the desired product.
4-(tert-Butyl)-2-(tert-butyldimethylsilyl)pyridine (3o): Follow General Procedure A, 4-(tert-butyl)pyridine (0.5 mmol, 1 equiv), tert-Butyldimethylsilane (290 mg, 2.5 mmol, 5 equivalents), Na2S2O8 (238 mg, 1.0 mmol, 2.0 equiv), Ir(ppy)2(dtbpy)PF6 (4.6 mg, 0.005 mmol, 0.01 equiv) and 5 mL DMSO/DCE (1:1) (0.1 M) is used. The product was isolated by flash chromatography (2% ethyl acetate/hexane) as a colorless oil (90 mg, 72%). 1H NMR ( MHz, CDCl3) δ 8.66 (dd, J = 5.3,0.6 Hz, 1H), 7.47 (dd, J = 2.1, 0.7 Hz, 1H ), 7.15 (dd, J = 5.3, 2.1 Hz, 1H), 1.28 (s, 9H), 0.89 (s, 9H),0.31 (s, 6H); 13C NMR (100 MHz , CDCl3) δ 165.76, 156.84, 149.68, 126.81, 119.48, 34.36, 30.47,26.50, 16.82, -6.33. HRMS (ESI) Calcd. for C15H28NSi [(M+H) +] 250.1986, found 250.1993.
General Method D for Hiyama-Denmark Cross-Coupling of Heteroarylsilane Products: To a 10 mL vial equipped with a Teflon septa and a magnetic stir bar, add the corresponding arylsilane (0.5 mmol, 1.0 equiv), corresponding Aryl iodide or bromide (1.0mmol, 2 equivalents), Pd (Ph3P)4 (0.025mmol, 0.05 equivalents) and Ag2 O (0. Calcium bicarbonate 5mmol, 1 equivalent). Seal the vial and place under nitrogen atmosphere, then add anhydrous DMF (5 mL, 0.1 M) and TBAF (0.25 mL, 0.5 equiv, 1 mmol/L in THF). The reaction was heated at 90°C for 4 hours. The reaction mixture was diluted with water and extracted with ethyl acetate (3 × 20 mL). The combined organic extracts were washed with brine (30 mL) and washed with anhydrous Na2SO4Dry and concentrate in vacuo. The crude S35 product was purified by silica gel flash chromatography using the specified solvent system to give the desired product.
4,4′-di-tert-butyl-2,2′-bipyridine (15): Follow the general procedure D of Hiyama-Denmark cross-coupling, using 4-(tert-butyl)-2-(tert-butyl) (dimethylsilyl)pyridine 3o and 2-bromo-4-(tert-butyl)pyridine, the crude mixture was purified by flash column chromatography (50% ethyl acetate/hexane) to give the title compound as white Solid (74mg, 55%). 1H NMR ( MHz, CDCl3)δ 8.58 (dd, J = 5.3, 0.4 Hz, 2H), 8.40 (d, J = 1.4 Hz, 2H), 7.28 (dd, J = 5.2, 2.0 Hz, 2H), 1.36 (s, 19H);13C NMR (100 MHz, CDCl3) δ 160.87, 156.44, 148.96, 120.64, 118.20, 34.90, 30.55. HRMS (ESI)Calcd. for C18H25N2 [(M+H)+] 269.2012, found 269.2015.
Synthetic methods and application examples of 4,4′-di-tert-butyl-2,2′-dipyridine
Synthetic methods and application examples of 4,4′-di-tert-butyl-2,2′-dipyridine Application 1.
CN202010695785.4 reports a synthesis method of benzoborazine thiophene derivatives. It uses bromoborazine, sulfide, catalyst, etc. as raw materials, and reacts at 90-140°C for 8-24 hours. Concentrate and purify to obtain benzoborazine thiophene derivatives; bromoborazine is a borazine monobromide or dibromide; the sulfide is calcium carbonate S8, K2S, Na2S or KSCN; the catalyst is palladium acetate, dibromide Triphenylphosphine palladium dichloride, [1,1-bis(diphenylphosphino)ferrocene]palladium dichloride, allylpalladium(II) chloride dimer, or cuprous iodide; ligands It is triphenylphosphine, 2-(di-tert-butylphosphine)biphenyl, 2,2′-dipyridine, 4,4′-di-tert-butyl-2,2′-dipyridine or 1,10-phenanthroline pholine; the basic salt is sodium carbonate, potassium carbonate, potassium acetate or sodium tert-butoxide. The method of the invention has the advantages of mild reaction conditions, wide application range of raw materials, specific reaction, high yield, and low environmental pollution.
Synthetic methods and application examples of 4,4′-di-tert-butyl-2,2′-dipyridine Application 2.
CN201911243504.5 reports the synthesis method of nickel-catalyzed C-3 alkyl-substituted quinoxalinone under electrochemical conditions, which belongs to the field of compound preparation technology.�. This method uses 2-hydroxyquinoxaline and N-hydroxyphthalimide ester as raw materials in a single-chamber electrolytic cell, and uses nickel chloride hexahydrate as a catalyst in the electrolyte, using 4,4′ -Di-tert-butyl-2,2′-dipyridine is used as the ligand, electrolyzed under the conditions of lithium perchlorate as the supporting electrolyte, the reaction temperature is 60°C, the current density is 8mA/cm2, and C with different structures can be obtained after 3 hours of reaction. -3-substituted alkylated quinoxalinone compounds. This method has a mild reaction, uses cheap and easily available nickel metal catalyst, and has good functional group compatibility. In addition, this electrochemical method provides a green and effective method for the synthesis of various alkyl-substituted quinoxalinone compounds, helping to achieve atom economy, greatly reducing costs and making operations simpler. ization, which is more conducive to the realization of industrialized production.
References
[1] Shihui, Liu, Peng, et al. Photocatalytic C-H silylation of heteroarenes by using trialkylhydrosilanes.[J]. Chemical Science, 2019.
[2] CN202010695785.4 Synthesis method of benzoborazine thiophene derivatives
[3] CN201911243504.5 Synthesis method of nickel-catalyzed C-3 alkyl-substituted quinoxalinone under electrochemical conditions
