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

摘要

The reaction of aromatic aldehyde 1 and 5,5-dimethyl-1,3-cyclohexanedione 2 under solvent-free and solid state conditions has been catalyzed by KF/Al_2O_3 or silica sulfate and yields two products: 2,2'-arylmethylene bis(3-hydroxy-5,5-dimethyl-2-cyclohexen-l-one) 3 and 1,8-dioxooctahydroxanthene 4 and their derivatives.In addition,2-amino-4-aryl-3-cyano-7,7-dimethyl-5-oxo-4H-5,6,7,8-tetrahydrobenzo[b]pyran 5 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.