Benzilic acid chloride

Baeyer-Villager oxidation, 10, 151, 433 Bamford-Stevens reaction, 402 Barton reaction, 253 Beckmann rearrangement, 140 Benzilic acid rearrangement, 418, 435 3 -Benzoyloxy-7-methylenecholest-5-ene, 60 Benzylmagnesium chloride, 64 3-Benzyloxycholesta-3,5-diene, 342... 

A mixture of 45.6 g. (0.2 mole) of benzilic acid (Note 1) in 700 ml. of anhydrous thiophene-free benzene, contained in a 2-1. three-necked flask fitted with a reflux condenser (attached to a calcium chloride drying tube) and a motor-driven sealed stirrer, is cooled in an ice bath until a crystalline mass results. To the stirred mixture is added, in one portion, 80 g. (0.6 mole) of anhydrous aluminum chloride. The stirred mixture is heated until refluxing begins and is maintained at this temperature for 3 hours. During this period much hydrogen chloride is evolved, and the initially yellow solution soon becomes deep red. The solution is cooled and decomposed by the cautious addition of small pieces of ice, and then 400 ml. of water is added cautiously, followed by 200 ml. of concentrated hydrochloric acid. The benzene is removed by steam distillation, and the product is separated by filtration from the hot mixture. The lumps of product are crushed and extracted with 400 ml. of boiling 10% sodium carbonate solution. The mixture is filtered, and the extraction is repeated on the undissolved residue with an additional 200 ml. of hot 10% sodium carbonate solution. The basic filtrates are... 

This interesting derivative of ketene is also obtained from benzilic acid by the old process of Staudinger the add is converted, by the action of phosphorus pentachloride, into diphenylchloracetyl chloride from which the two chlorine atoms are removed by means of zinc. (Formulate this equation.) What is carbon suboxide For information about the ketenes see H. Staudinger, Die Ketene, Stuttgart, 1912. 

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... 

Anions generated by cathodic reduction of carbonyl compounds, benzyl-chloride or activated double bonds can be trapped by addition to C02. With benzophenone the carbonate of benzilic acid was obtained (Eq. (134) ) 304 ... 

Although 1,2-dicarbonyl substrates (especially unsymmetrical benzils) are often difficult to make, there are a number of approaches which may be appropriate. Propane-1,3-dithiol reacts with aldehydes to give cyclic thioacetals (in 52-91% yields) which form stable dithiane anions when treated with butyllithium. Subsequent quenching with an acid chloride followed by mercury(ll) chloride treatment gives a 1,2-dicarbonyl species. Alternatively, substitution of an aldehyde for the acid chloride gives rise eventually to an a-hydroxycarbonyl derivative (Scheme 5.1.2) [16j. An alternative approach to a-ketoaldehydes (82-86% yields) reacts an a-ketonitrate ester with sodium acetate in DMSO [17]. Aryl a-diketones can be made from a-ketoanils, which are in turn made by cyanide ion-catalysed transformation of aromatic aldimines [18], and the range of unsymmetrical benzils has been increased by... 

Acid-catalyzed cyclizations have been used to synthesize 1,4-diazocines. The benzilic acid amide 27 was converted into benzodiazocinone 28 (65KGS476). DeMartino et al. reported that treatment of 29 (R = NHAc, R = H) and 29 (R = NHCOPh, R = H) with phosphoryl chloride afforded... 

Preparation. Staudinger prepared diphenylketene for the first time by the action of zinc turnings in ether on a-chlorodiphenylacetyl chloride, an intermediate now readily available by the action of phosphorus pentachloride on benzilic acid (1), but evidently the yield was poor. He then tried dehydrohalogenation of... 

Benzils from carboxylic acid chlorides 2 RCOC1 —> RCOCOR... 

Oxalyl chloride affords diketones (benzene gives benzil) but under the reaction conditions oxalyl chloride decomposes partly to phosgene, so that the acid chloride or monoketone may also be formed.606 The method thus has value also for preparation of carboxylic acids as examples, carboxylation of mesitylene in 65-70% yield by oxalyl chloride is recorded in Organic Syntheses,601 and l,l-di-(p-tolyl)ethylene gives 3,3-di-(/ -tolyl)acrylic acid in 80% yield.608... 

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