The reaction of aromatic aldehydes and 5,5-dimethyl-1,3-cyclohexanedione under solvent-free grinding conditions

Abstract

The reaction of aromatic aldehyde <b style="">1</b> and 5,5-dimethyl-1,3-cyclohexanedione <b style="">2</b> under solvent-free and solid state conditions has been catalyzed by KF/Al₂O₃ or silica sulfate and yields two products: 2,2′-arylmethylene bis(3-hydroxy-5,5- dimethyl-2-cyclohexen-1-one) <b style="">3</b> and 1, 8-dioxooctahydroxanthene<b style=""> 4</b> and their derivatives. In addition, 2-amino-4-aryl-3-cyano-7,7-dimethyl-5-oxo-4<i>H</i>-5,6,7,8-tetrahydrobenzo[<i style="">b</i>]pyran <b style="">5</b> is also obtained in this condition. This method provides several advantages such as good yield (61-93%), simple work-up procedure and is environment friendly.