Benzophenone Beckmann rearrangement

Beckmann rearrangement of benzophenone oxime to benz-anilide. Dissolve 2 g. of benzophenone oxime in 20 ml. of anhydrous ether in a small conical flask and add 3 g. of powdered phosphorus pentachloride (or 3 ml. of pure tbionyl chloride). Distil off the solvent and other volatile products on a water bath CAUTION ether), add 25 ml. of water, boil for several minutes and break up any lumps which may be formed. Decant the supernatant liquid, and recrystallise, in the same vessel, from boiling alcohol. The product is benzanilide, m.p. 163° confirm this by a mixed m.p. determination with an authentic specimen. 

Oximes of ketones undergo rearrangement (the Beckmann rearrangement) to amides under the influence of a variety of acidic reagents (e.g. sulphuric acid, hydrogen fluoride, acetic anhydride, phosphorus pentachloride, thionyl chloride, etc.). The process is illustrated by the conversion of benzophenone oxime to benzanilide in the presence of phosphorus pentachloride. 

Beckmann rearrangement of benzophenone oxime to benzanilide. Dissolve 2 g of benzophenone oxime in 20 ml of anhydrous ether in a small conical flask and add 3 g of powdered phosphorus pentachloride (or 3 ml of pure thionyl chloride). Distil off the solvent and other volatile products on a water bath on... 

Example 4.32. Beckmann rearrangement of benzophenone oxime. The overall reaction is as follows ... 

Beckmann Rearrangement.— The special interest in connection with this compound is its formation from benzophenone oxime by the Beckmann rearrangement (p. 654). 

Rearrangements. Horning and Stromberg found PPA an excellent solvent-reagent for effecting Beckmann rearrangement of ketoximes°° and aldoximes.° For example, benzophenone oxime (2 g.) when stirred manually with PPA (60 g.) at 130° dissolved in about 10 min., and after dilution of the clear solution with water... 

InCls can be used as an efficient reagent for the conversion of aldoximes to nitriles and ketoximes to amides. Benzaldoxime gives benzonitrile, and benzophenone oxime is converted to the Beckmann rearrangement product, benzanilide, in 95% yield (Scheme 8.135) [179]. Sonication of a mixture of a carbonyl compound, an amine, and diethyl phosphite in fhe presence of a catalytic amount of InCls produces a-aminophosphonate (Scheme 8.136) [180]. 

Beckmann rearrangement. Aryl alkyl ketone oximes (acetophenone oxime) or diaryl ketone oximes (benzophenone oxime) undergo Beckmann rearrangement when refluxed with anhydrous or hydrated pyridine hydrochloride. If the ketone has a methoxyl group in the para position concomitant demethylation occurs.15... 

The CR NR group can be introduced into ammonia, amines, hydroxy compounds, carboxamides, and sulfonamides to form amidines, imido-esters, etc., via imidosulfonates, obtained by the Beckmann rearrangement of oxime sulfonates.—B Benzophenone oxime benzene sulfonate and aniline warmed in benzene, and, after the exothermic reaction has ceased, further refluxed for 15-30 min. —>- N,N -diphenylbenzamidine. Y 92.5%. (F. e. s. P. Oxley and W. F. Short, Soc. 1948,1514.)... 

Oximes are readily sulfonylated by sulfenes to yield the O-sulfonyl oximes (53)91,134-136 (equation 45). Aldoxime sulfonates (53, R = H) are easily converted to the nitriles, RC=N134, while the benzophenone derivative (53, R,R = Ph) undergoes the Beckmann rearrangement to benzanilide91. Attempts to observe cycloaddition of sulfenes and nitrile oxides led to a-chloroaldoxime sulfonic esters (53, R = Q)134 136,145. It is not known if the... 

Fresenius, passing his pharmacy examination in 1877. He then joined Kolbe, and his assistant, Ernst von Meyer, and started work on the oxidation of dialkyl sulfides. For this research Beckmann received his PhD in July 1878. Beckmann tried to apply an already-known reaction to discriminate between aldehydes and ketones. This reaction involved the use of hydroxylamine to convert benzophenone into an oxime. Treating this oxime with phosphorus pentachloride he converted it into a substance already characterized by Wallach. This reaction is now known as the Beckmann rearrangement. 

The one pot synthesis of amide 18 was accomplished within 2 min. by P205/Si02 catalyzed Beckmann rearrangement of the ketone 17 under microwave irradiation." Other ketones such as cyclohexanone, benzophenone, acetophenone and benzil furnished the rearranged products in excellent yields. 

Beckmann rearrangement of benzophenone oxime to PhC(Cl)=NPh (82%) is promoted by Ph3PCl2/Et3N in CH2CI2 at rt. Cyclopentanone and cyclohexanone oxime are converted to 8-valero- and e-caprolactam (76 and 86%) with PhsPCh in PhH at 50-60 The action of heat... 

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