Dypnone oxide

Waaserman and Aubrey1 extended this type of investigation lo include the cw- and trans-isomers of dypnone oxide. Chtarohydrins obtained on treatment of these ,j9-epoxy ketones with hydrogen chloride in aoetic acid could be recydized into dypnone oxides of... 

Not only Cc,-0 and rarely Cg-O bond breaking but C -Cg bond splitting may be observed. A consequence of this is the very stereoselective epimerization of benzylidenecyclohexanone oxide.The stereochemistry of photolysis of optically active dypnone oxide has been studied and the possibility of C-C bond cleavage has likewise been proposed.C-C bond splitting has also been observed during examinations of chalcone oxides transformation to dibenzoylmethane, trans-cis isomerization, and photofragmentation occur via ylides and acylcarbene intermediates (Eq. 341). ... 

Condeilsation. Although aluminum alkoxides are effective in bringing about the mesityl oxide type condensation of ketones, as, for example, in the formation of dypnone (XXVII) from acetophenone (XXVI), aluminum isopropoxide rarely induces this reaction to any significant degree in the reduction of ketones. 

It was assumed that the mechanism resembles to some extent the mechanism of the Fischer reaction. Undoubtedly, the primary products of the reactions are the Schiff bases 466 and 467. The former can be isolated if the reaction is carried out at a lower temperature. The formation of 467 is supported by the noticeably increased yield of 468 if mesityl oxide or dypnone are used in reaction instead of acetone or acetophenone. Further steps include tautomerization of Schiff base 467, the attack by the terminal methylene group on electron-defficient position 2 in the imidazole ring, the cleavage of an N—N bond, and recyclization followed by aromatization with elimination of a molecule of ammonia. 

An interesting application of this reaction was the use of macro-molecular anhydrides, namely, styrene-maleic anhydride or vinyl acetate-maleic anhydride copolymers in the presence of perchloric acid as catalyst, these copolymers acylate mesityl oxide or dypnone to macromolecular pyrylium salts which, with aryl substituents, are fluorescent.307,308 No crystalline products could be obtained from succinic anhydride because of the solubility and ease of decarboxylation. 

The mechanism of photo-oxidative degradation of polystyrene was also investigated using low molecular compounds such as benzene 3-phenyl-pentane [1356] 2-phenylbutane [1360, 1361] 1,3-diphenylpropane-l-one [719, 725] 1,3-diphenylpropane 1,3-diphenylbutane 2,4-diphenylpentane [1293] cumene cumene hydroperoxide [759] acetophenone hexanoic acid 3-heptanone y-valerolactone 2-phenyl-2-propanol [1250, 1397] benzal-dehyde benzoic acid l-3-diphenyl-propanone-3 l,3-diphenyl-buten-2,3-on-l (dypnone) l,3-diphenylpropen-2,3-on-l (chalcone) l-phenyl-butanedion-2,3 l-diphenylpropanedion-1,2 l-phenyl-butanedion-1,3 phenylacetic aldehyde l,5-diphenyl-pentanone-3 4-phenyl-butanone-2 [1250]. 

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