110624-05-0Relevant articles and documents
PHOTOLYSIS OF CYCLIC ACETALS OF ARYL BENZOYLACETATES AS THE KEY STEP IN A NEW SYNTHESIS OF FLAVONES
Garcia, Hermenegildo,Iborra, Sara,Miranda, Miguel A.,Primo, Jaime
, p. 2511 - 2517 (2007/10/02)
Although the yields found for the photo-Fries rearrangement of the aryl benzoylacetates 1 are poor, blocking of the carbonyl group, as in the related acetal derivatives 3, results in a substantial preparative improvement.Thus, the o-hydroxydibenzoylmethanes 2 are obtained from 1 with an average yield of 18percent, while the corresponding acetals 4 are obtained from 3 with an average yield of 58 percent.Compounds 4 are efficiently converted into flavones 8 by means of wet silica gel, through hydrolysis of the acetal moiety and subsequent cyclization of the resulting o-hydroxydibenzoylmethanes 2.