3-Phenylprop-2-Enal → 2,3,6-Triphenylcyclohexenone

Beteiligte Stoffe

Reaktionsschritte

2,3,6-Triphenylphenol was prepared according to A. S. Hay and R. F. Clark (Macromolecules, 3, 533, 1970). 11.36 g (54 mmoles) of dibenzylketone, 7.14 g (54 mmoles) of cinnamaldehyde and 5 mL of diethylamine were mixed and the solution became yellow and after 20 min. a yellow solid deposited. The solid was added to ethanol (80 mL), cooled and filtered to yield 2,3,6-triphenylcyclohexenone (91%). The product (8.0 g) was mixed with 1 g of 5% Pd on carbon and heated at 270° C. for 30 min and then cooled. The mixture was dissolved in hot ethylacetate and the hot solution was filtered and cooled to yield 2,3,6-triphenylphenol (69%). The oxidation of triphenylphenol (5 g) was carried out in butyronitrile (50 mL) with a CuCl catalyst (0.4 g) by passing oxygen through the stirred solution at 100° C. for 8 hours. The reaction mixture was cooled and filtered to yield (82%) of the crude biphenol. Reduction with a few drops of hydrazine in hot acetic acid reduced any of the diphenoquinone in the product to give 2,2',3,3',5,5'-hexaphenyl-[1,1'-biphenyl]-4,4'-diol which was further purified by crystallization.

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