67% |
With palladium diacetate; potassium carbonate; tris-(o-tolyl)phosphine In ethanol; water; toluene at 90℃; for 9h; Inert atmosphere; |
5.5.1 Step 1: Synthesis of 3,5-bis(4-cyclohexylphenyl)aniline
Into a 200 mL three-neck flask were put 0.87 g (3.5 mmol) of 3,5-dibromoaniline, 2.0 g (7.0 mmol) of 4-cyclohexylphenylboronic acid pinacol ester, and 0.28 g (0.92 mmol) of tri-ortho-tolylphosphine, and the air in the flask was replaced with nitrogen. After 20 mL of toluene, 5 mL of ethanol, and 7 mL of a 2M aqueous solution of potassium carbonate were added to this mixture and the mixture was degassed under low pressure, 40 mg (0.18 mmol) of palladium(II) acetate was added to the mixture, and the mixture was stirred for 9 hours at 90° C. under a nitrogen stream. After the stirring, water was added to the mixture, and an aqueous layer was subjected to extraction with toluene. The obtained solution of the extract and an organic layer were combined, and the mixture was washed with water and saturated brine. Then, the mixture was dried with magnesium sulfate. This mixture was separated by gravity filtration, and the obtained filtrate was concentrated to give a brown oily substance. This solid was purified by silica gel column chromatography (developing solvent: toluene) to give 0.95 g of a target brownish white solid in a yield of 67%. A synthesis scheme of Step 1 is shown in (e-1) below. Results of 1H NMR measurement of the brownish white solid obtained in Step 1 are shown below. The results show that 3,5-bis(4-cyclohexylphenyl)aniline was obtained.1H NMR (CD2Cl2, 300 MHz): σ=7.56-7.53 (m, 4H), 7.30-7.27 (m, 4H), 7.17-7.16 (m, 1H), 6.86 (d, J=1.5 Hz, 2H), 3.87 (bs, 2H), 2.59-2.51 (m, 2H), 1.92-1.74 (m, 10H), 1.50-1.23 (m, 10H). |