Dibenzoyl methane derivatives

Aluminum hydroxide carboxylic acid salts of dibenzoyl methane derivatives, (IV), are also effective as UV-A absorbers (4). 

Except for the tetraisopropoxoalnminates of cerium(iv) and thorium with aluminium, diisopropoxozirconium bis-tetraisopropoxoaluminate derivatives of the type [(Pr 0)2Al(/i-0lV)2Zr(0IV)2(/i-0Pr )2Al(0Pr )2] can only be obtained in the case of smaller zirconium atoms. The structure of this derivative, those of ZrAl2(OPr )io-4 L ( (where L = acetylacetone, benzoylactone, dibenzoyl methane, methylacetoacetate, or ethylacetoacetate), have been elucidated mainly by H NMR studies and can be represented by... 

Recently, the synthetic utility of dimethyl formamide (DMF) as the nucleophilic trigger in aryne MCRs was developed independently by the Miyabe and Yoshida groups. The three-component coupling reaction between aryne, DMF, and an active methylene compound such as acetyl acetone, dibenzoyl methane, cyclohexane 1,3-dione, etc. resulted in the formation of either 2H-chromenes 105 or coumarin derivatives 106 [75,76]. The insertion of fhe carbonyl group of DMF to the aryne generates the o-quinone methide intermediate 104. Subsequent reaction of 104 with cyclic or acyclic 1,3-diketones as the third component resulted in the formation of 2H-chromenes 105. Intriguingly, furnished coumarin derivatives 106 were formed when 3-ketoester or a-(hetero)aryl esters were used as the third component (Scheme 53). 

---