A NEW SYNTHESIS AND APPLICATION OF 1-ARYL-2,4-DIONES

Methyl ketones or ethyl acetate react with aromatic alpha-bromo ketone s in the presence of two equivalents of tert-butoxy- or diethylaminoma gnesium bromide in benzene (toluene) under reflux to produce 1-aryl-2, 4-diones. The conversion, apparently, occurs via aldol condensation an d subsequent [1,2]-sigmatropic rearrangement of the intermediate 3-bro mo-2-hydroxy ketones. A number of fused aromatic and heteroaromatic ph enols have been prepared by cyclodehydration of 1-aryl-2,4-diones.