Benzil, from decomposition

Diphenylacetic acid has been obtained by the reduction of benzilic acid with hydriodic acid and red phosphorus 1 by the treatment of phenylbromoacetic acid with benzene and zinc dust,2 or with benzene and aluminum chloride 3 by the hydrolysis of diphenylacetonitrile 4 by heating a-diphenyldichloroethyl-ene with alcoholic sodium ethylate 5 by heating benzilic acid 6 from diphenylmethane, mercury diethyl, sodium and carbon dioxide 7 by the oxidation of a,a,5,S-tetraphenyl- 8-butine 8 by the decomposition of some complex derivatives obtained from diphenylketene 9 by the hydrolysis of diphenyl-5,5-hydan-toin 10 by the treatment of diphenylbromoacetic acid with copper 11 by the oxidation of dichlorodiphenylcrotonic acid.12... 

Komoto detected lactic acid in the mixture from reaction of D-glucose with ammonia,4 and presumed that it was produced from pyruvaldehyde formed by decomposition of D-glucose. Lactic acid has, indeed, been found as a product of the action of alkali (lime-water) on substituted D-glucose and substituted D-fructose,81,83,96 and the mechanism of its formation involves the reversible aldol reaction, followed by formation of pyruvaldehyde, and the benzilic acid rearrangement already described for saccharinic acid this is illustrated83,96 in Scheme 11. 

Steady-state irradiation of Eosin and PDO leads to the formation of ethyl benzoate, benzil, and benzoyloxycarboxylate. Energy transfer from Eosin to PDO is unfavorable and the decomposition of PDO is most likely sensitized by electron transfer. In addition, at the concentration of PDO employed the fluorescence of Eosin is not significantly quenched and it is concluded that the excited state involved is the triplet of Eosin. 

A hot solution of 50 g. (0.24 mole) of benzil (Org. Syn. Coll. Vol. 1, 80) in 75 cc. of methyl alcohol is prepared, and the above solution, heated to 6o°, is added. Most of the benzil hydrazone separates immediately, but the yield is increased by refluxing a half hour. The hydrazone is filtered from the cold solution and washed with a little ether to remove the yellow color. The yield is 5°-5 g- (94 Per cent °f the theoretical amount), melting at 147-1510 with decomposition. 

Many decomposition products of DHA are probably the same as those observed in the decomposition of AA (40), Fifteen products from DHA decomposition in aqueous solution were reported (41), Of these fifteen, the five main volatile products were 3-hydroxy-2-pyrone, 2-furan-carboxylic acid, 2-furaldehyde, acetic acid, and 2-acetylfuran. DHA also undergoes a benzilic acid rearrangement in alkaline solution (42),... 

Both N-N and N-C bond fission occurs on irradiation of the hydrazone derivatives (191). The photodegradation of the phenylhydrazone and the hydrazone of benzil have also been described. a-Ketoiminyl radicals are formed on irradiation of oximino ketones at low temperature. A study of the photochemical decomposition of sulfamic esters and their use as initiators of cross-linking of a melamine resin have been described. The bispyridinyl radical (192) is formed by one electron reduction of the corresponding pyridinium salts. The irradiation of this biradical at 77 K results in C-N bond fission with the formation of benzene-1,3-diyl. The predominant products from the irradiation (X,> 340 nm) of (193) in methanol were identified as A -hydroxy-2-pyridone and (194) from the fission of the C-O bond. Other products were 2-pyridone, (195) and (196) that arise from O-N bond fission. The reaction is to some extent substituent dependent and a detailed analysis of the reaction systems has identified an intramolecular exciplex as the key intermediate in the C-O bond heterolysis. 

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