A Facile Synthesis of Derivatives of Tetraphenylcyclopentadienone and a Linear Polymer

A proficient and quick approach has been developed for the synthesis of tetraphenylcyclopentadienone ( 3a ) and its derivatives ( 3b – 3f ) from the condensation of 1,3-diarylpropan-2-ones ( 1a – 1f ), and benzil ( 2 ) using sodium ethoxide as a base. Using the developed protocol, a series of 2,5-diaryl-3,4-diphenylcyclopentadienones ( 3a – 3f ) have been prepared in high yields (up to 95%). The preparation of a linear polymer has been carried out in four steps. The reduction of the nitro groups present in the 2,5-bis(4-nitrophenyl)-3,4-diphenylcyclopenta-2,4-dienone ( 3b ) to get 2,5-bis(4-aminophenyl)-3,4-diphenylcyclopenta-2,4-dienone ( 4 ), which was further reacted with 2‑bromo-2-methylpropionyl bromide to produce N , N '-((2-oxo-4,5-diphenylcyclopenta-3,5-diene-1,3-diyl)bis(4,1-phenylene))bis(2-bromo-2-methylpropanamide) ( 5 ). The resultant compound 5 served as an initiator of an atom transfer radical polymerization of tert-butyl acrylate to yield poly(t-butyl acrylate) ( 6 ). The ester groups were hydrolyzed (acid-catalyzed) to get polyacrylic acid with functional group located in the middle of the chain. All the derivatives were characterized by spectroscopic techniques. The important features of the present protocol are very short reaction times, performance simplicity, high yields, and synthesis of a linear polymer, which might have the potential to show high luminous efficiency, good thermal stability, and could be fabricated into organic light-emitting diodes.