Improved synthesis of 2,2′-arylmethylene bis(3-hydroxy-5,5-dimethyl-2-cyclohexene-1-one) derivatives catalyzed by urea under ultrasound

Synthesis of 2,2′-arylmethylene bis(3-hydroxy-5,5-dimethyl-2-cyclohexene-1-one) derivatives catalyzed by urea via the condensation of aromatic aldehydes and 5,5-dimethyl-1,3-cyclohexanedione was carried out in 80–98% yields at 50 °C in aqueous media under ultrasound. This method provides several advantages such as environment friendliness, high yields and simple work-up procedure.