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By the Beckmann rearrangement

A mixture of benzothieno[2,3-d]- and benzothieno[3,2-d]-azocines (194 and 195) is produced in 43% overall yield by the Beckmann rearrangement of the mixture of oxime isomers 193 with phosphorus pentoxide in dichloromethane (90JCS(P1)1083 Scheme 53). [Pg.110]

Some other syntheses of y-lactams by the Beckmann rearrangement were also tested without great success, the nitrile being the major product of the transformation (equations 130 and 131). [Pg.427]

During the synthesis of ligands for the vesicular acetylcholine transporter, a octahy-droquinoline nucleus 361 was prepared via a ring-expansion rearrangement followed by a hydride reduction (equation 140). The yield was moderate but only one lactam 360 was produced by the Beckmann rearrangement. [Pg.431]

Nine-membered lactam rings can also be produced by the Beckmann rearrangement. The azonane ring 420 was selectively formed from an eight-membered cyclic ketone 419 by a rearrangement/reduction sequence (equation 175). [Pg.444]

The deactivation and regeneration of the catalyst are also important processes in the industrial production of the caprolactam by the Beckmann rearrangement and have been... [Pg.472]

A range of 2,2-bis(trifluoromethyl)-l,3-oxazepin-5-ones (334) has been prepared by the reaction of oxazolidin-5-ones with 1-diethylamino-l-propyne (75TL3223). l,3-Oxazepan-2-one has been prepared by the Beckmann rearrangement of tetrahydro-2-pyranone oxime. [Pg.627]

The synthesis of aza-2-cycloheptanone (e-caprolactam) by the Beckmann rearrangement of the oxime of cyclohexanone is of commercial importance because the lactam is an intermediate in the synthesis of a type of nylon (a polyamide called nylon-6 2) ... [Pg.1181]

When the reaction is carried out in boiling DMSO, no significant gain in the yield of benzamide (30%) is observed. Since under these conditions the primary dehydration of aldoximes is evident, the formation of benzamide is most likely to result from hydration of the intermediate benzonitrile rather than by the Beckmann rearrangement scheme. [Pg.251]

Caprolactam can be made by the Beckmann rearrangement of the oxime f of cyclohexanone. (Check that you can draw the mechanisms, of both these reactions and look at Chapters 14 and 37 if you find you can t.) Cyclohexanone used to be made by the oxidation of cyclohexane with molecular oxygen until the explosion at Fiixborough in Lincolnshire on 1 June 1974 that killed 28 people. Now cyclohexanone is made from phenol. [Pg.1454]

This compound is in turn converted to the corresponding oxime by reaction with hydroxy-lamine, and cyclohexanone oxime is made into caprolactam by the Beckmann rearrangement. [Pg.456]

Acetyl-5-bromothiophene has been converted to 2-acetamido-5-bromothiophene in 37% yield by the Beckmann rearrangement of its oxime <2006S1295>. [Pg.803]

Certain amines are conveniently prepared by the hydrolysis of N substituted amides which are made by the Beckmann rearrangement (method 359) and the Schmidt reaction (method 362). [Pg.791]

The proofs that the known form is the syn compound are that it does not break up and yield phenyl cyanide and that it yields acet anilide by the Beckmann rearrangement which has just been discussed (p. 654). [Pg.657]

Beckmann Rearrangement.— The special interest in connection with this compound is its formation from benzophenone oxime by the Beckmann rearrangement (p. 654). [Pg.685]

Caprolactam (preceding problem) can be made by the Beckmann rearrangement. With what ketone must the process start ... [Pg.1051]

Dimethylaniline has been prepared by reduction of the corresponding nitro compound, either chemically or catalyti-cally. It has been prepared from 3,4-dimethylphenol by heating with ammonia, ammonium bromide, and zinc bromide from w-toluidine hydrochloride by alkylation with methanol at high temperatures from anhydro-4-amino-2-methylbenzyl alcohol by dry distillation from calcium hydroxide from 2-methyl-S-aminobenzyl alcohol by reduction with sodium from 2-methyl-5-nitrobenzyl chloride and 2-methyl-S-nitrobenzyl acetate by catalytic reduction from o-xylene by direct amination with hy-droxylamine hydrochloride in the presence of aluminum chloride and from 3,4-dimethylacetophenone by the Beckmann rearrangement of the oxime.i" The present method has been published. ... [Pg.48]

His, S., Meyer, C., Cossy, J., Emeric, G., Greiner, A. Solid phase synthesis of amides by the Beckmann rearrangement of ketoxime carbonates. Tetrahedron Lett. 2003, 44, 8581-8584. [Pg.548]

Table 4. Synthesis of Aminocyclopropane Lactams by the Beckmann Rearrangement of Cyclopropyl Ketone Oximes... Table 4. Synthesis of Aminocyclopropane Lactams by the Beckmann Rearrangement of Cyclopropyl Ketone Oximes...
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.)... [Pg.355]

Compound 30 was prepared by the Beckmann rearrangement in polyphosphoric acid of the diphenylhydrazone 32 (R = Me). The reaction also worked for the benzyl analogue 32 (R = CH2Ph), but the 3-unsubstituted analogue could not be prepared from 32 (R = H), as this compound on acid treatment hydrolyzed back to the ketone 33. Phos-phoryl chloride converted 30 into the corresponding 4-chloroimidazo[l,5-ajquinoxaline. [Pg.659]

E-Caprolactam is an important starting material for the production of nylon-6. It is synthesized by the Beckmann rearrangement reaction of cyclohexanone oxime catalyzed by a solid acid catalyst. Many solid acid catalysts, such as mixed boron oxide [1-3], Si02-Al203 [4,5], metal phosphates [6-8] and moclified zeolites [3,9-12], are reported to catalyze the cycdohexanone oxime rearrangement. The acid function of the catalyst is essential to effect the rearrangement reaction. [Pg.615]

Cyclohexanone oxime is converted quantitatively to caprolactam with oleum by the Beckmann rearrangement as shown as follows ... [Pg.193]

In a process developed to commercial maturity by DuPont, and industrially practiced by this company from about 1963 to 1967 [121], cyclohexanone oxime is obtained by a route that encompasses the nitration of cyclohexane to nitrocyclohexane and the reduction of the latter to the oxime, which is converted to caprolactam by the Beckmann rearrangement. According to U.S. Patent 2,634,269, nitrocyclohexane can be converted directly to caprolactam in the gas phase at 25(F450°C using a polyborophosphate catalyst. [Pg.62]

The cyclohexanone oxime obtained by any of these processes (1, 2,4, 6, and 7, in Figure 2.11) is converted to caprolactam by the Beckmann rearrangement in oleum. The resulting caprolactam sulfate is neutralized with ammonia and purified. The neutralization process yields about 2 + 0.2 kg of ammonium sulfate/kg of caprolactam. The lactam purification may entail extraction with organic solvents (toluene, benzene, chlorinated aliphatic hydrocarbons) followed by extraction of the organic solution with water and subsequent isolation of the lactam by either crystallization or distillation. Newer developments are concerned with the gas-phase catalytic rearrangement of cyclohexanone oxime using a boric acid on carbon catalyst in a fluidized-bed operation [122],... [Pg.63]

Amides are usually obtained from their oximes by the Beckmann rearrangement. We found it very difficult to prepare the DHBP oxime with the reasonable yield,accord-... [Pg.266]


See other pages where By the Beckmann rearrangement is mentioned: [Pg.242]    [Pg.607]    [Pg.631]    [Pg.925]    [Pg.607]    [Pg.631]    [Pg.364]    [Pg.60]    [Pg.925]    [Pg.26]    [Pg.31]    [Pg.364]    [Pg.607]    [Pg.631]    [Pg.60]    [Pg.200]    [Pg.308]    [Pg.31]   
See also in sourсe #XX -- [ Pg.1415 , Pg.1653 ]




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