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Nitrile-forming

The Oximation process depends on the fact that citronellal oxime, produced by shaking in the cold with a solution of hydroxylamine, is converted on heating with acetic anhydride into a nitrile which is not affected by saponification with alcoholic potash. The difference between the molecular weight of the nitrile formed and that of citronellal is so small as to be negligible, and the calculation of the percentage of geraniol from the saponification value is made by the usual formula. The method of procedure is as follows —... [Pg.335]

Under a pressure of 4,5 ml the 1 methyl-4-phenyl-piperidine-4-carboxylic acid nitrile passes over at a temperature of about 148°C in the form of a colorless oil under a pressure of 6 ml it passes over at about 158°C. After having been allowed to cool the distillate solidifies completely to form a crystalline mass. Its solidification point is at 53°C the yield amounts to about 135 parts, that is, about % of the theoretical yield. When recrystallized from isopropyl alcohol the hydrochloride of the nitrile forms colorless crystals, readily soluble in water and melting at 221° to 222°C. [Pg.932]

A plausible mechanism for the [2+2+2] cycloaddition reactions between diynes and heterocumnlenes (or nitriles) is shown in Scheme 5.16. Initially [2+2] oxidative addition of one alkyne and the heterocnmnlene (or nitrile) forms the five-mem-bered intermediate 54 compound 55 is formed after the insertion of the second alkyne and finally the seven-membered compound 55 undergoes reductive elimination to afford the prodnct 56 and regenerate the Ni(0) catalyst. [Pg.140]

If the solution becomes too alkaline, the nitrile formed will add to a second molecule of unsaturated ketone so readily that the product will consist almost entirely of a high-melting (284-286°) substance. For this reason it is essential to measure the acetic acid accurately if too much is used, addition of hydrocyanic acid will not take place. [Pg.104]

In contrast to the RCN/RNC equilibrium [17], where the nitrile form is the more stable one, silanisonitrile 23 is much lower in energy than silanenitrile 24. [Pg.137]

In many of its reactions hydrocyanic acid behaves as the nitrile of formic add H.CN. Many facts, in particular its great chemical and pharmacological similarity to the isonitriles >C = NR suggest another constitution, namely, that of carbimide >C =NH with bivalent carbon. The addition reactions of the nitriles (see above), which reactions are also characteristic of hydrocyanic acid, can equally well be explained on the basis of this second structural formula. In the nitrile form it is at the triple bond between carbon and nitrogen that addition takes place. In the methylene form this occurs at the two free valencies of the bivalent carbon atom, e.g. ... [Pg.139]

Nitrile-forming anti eliminations from the (Z)-oximes (31) and (32) have also been found to proceed by the E2 mechanism the symmetrical transition state is little... [Pg.398]

You will have noticed that the nitrile formed in this reaction contains one more carbon atom than the original monohaloalkane. This makes the reaction very useful in synthetic organic chemistry because it is a way to increase the chain length of an organic compound. [Pg.58]

The role of ferrous ions in modifying the enzymatic degradation of glucolimnanthin is not completely understood. It is known that species of Brassica produce the so-called nitrile-forming enzymes, such as the epispecifier protein, that require ferrous ions at micromolar concentrations [18]. When we incubated... [Pg.150]

Burow M, Marker J, Gershenzon J, Wittstock U (2006) Comparative biochemical characterization of nitrile-forming proteins from plants and insects that alter myrosinase-catalysed hydrolysis of glucosinolates. FEES J 273 2432-2446... [Pg.155]

Various reactions leading to by-products occur to all catalysts and, especially, the unsaturated nitriles formed by Beckmann fragmentation are easily polymerized. [Pg.472]

Much lower yields are achieved when terminal alkynes react with HCN. Terminal nitriles formed due to mainly steric factors are the main products. Regio- and stereoselectivities similar to those in hydrocyanation of alkenes indicate a very similar mechanism. [Pg.301]

Leupeptin is a slow, tight-binding inhibitor of trypsin. Some peptide aldehydes are potent, reversible inhibitors of cysteine proteases forming hemith-ioacetals with the active site cysteine.1 Similarly, peptide nitriles form thioimidate adducts.h... [Pg.622]

Reaction XLIX. (a) Action of Cuprous Potassium Cyanide on Aromatic Diazonium Compounds. (Sandmeyer). (B., 17, 1633, 2650 18, 1492, 1496.)—If a diazonium salt is added to a hot solution of cuprous-potassium cyanide, and the whole boiled on a water hath, nitrogen is evolved, and the corresponding nitrile formed. (C. r., 183, 421.)... [Pg.154]

In the following preparation, the amino-nitrile formed is hydrolysed directly to the corresponding amino-acid. These latter are of great importance in the chemistry of the proteins. [Pg.157]

Table 3 Yields of a-Arylated Nitriles Formed in the Photostimulated Reaction of a-Cyanoalkyl Anions with Aryl... Table 3 Yields of a-Arylated Nitriles Formed in the Photostimulated Reaction of a-Cyanoalkyl Anions with Aryl...
Shibasaki and co-workers applied (BINOL)Al(III)-derived catalyst 5a, previously developed for the cyanation of aldehydes [28], to the asymmetric Strecker reaction. This catalyst proved to be highly enantioselective for both aromatic and a,p-unsaturated acyclic aldimines (>86% ee for most substrates) (Scheme 8) [63-65]. Aliphatic aldimines underwent cyanide addition with lower levels of enantioselectivity (70-80% ee). A significant distinction of 5 relative to other catalysts is, undoubtedly, its successful application to the hydrocyanation of quinolines and isoquinolines, followed by in situ protection of the sensitive cx-amino nitrile formed (this variant of the Strecker reaction is also known as the Reissert reaction [66]). Thus, Shibasaki has shown that high enantioselectivities (>80% ee for most substrates) and good yields are generally obtainable in the Reissert reaction catalyzed by 5b [67,68]. When applied to 1-substituted... [Pg.124]

Hydrolysis of the nitriles formed to amides and/or acids in 2 N NaOH at 65-100°C was also observed by Brady and Jarrett (50JCS1227), who investigated transformations of acylated halobenzaldehydes in the presence of alkalies. [Pg.252]

Elimination reactions of ( )- and (Z)-benzaldehyde Opivaloyloximes (19a) and (19b) with DBU in MeCN have been found to occur by a nitrile-forming E2 mechanism which is ca 2000-fold faster for the latter isomer in each case.15 The corresponding Hammett substituent constants, activation parameters, and primary deuterium isotope effects, suggest that the anti elimination from (19b) (for which p = 2.4 0.1, H/ D = 2.7 0.3, A/H = 12.5 0.2 kcal mol-1, and A= —31.0 0.6eu) proceeds to (20) via a more symmetrical transition state with a smaller degree of proton transfer, less charge development at the jS-carbon and greater extent of triple bond formation than for syn elimination from (19a) (for which p = 1.4 0.1, kn/kn = 7.8 0.3, AH = 8.8 0.1 kcal mol 1 and A= -23.6 0.4 eu). [Pg.366]

The deuterium KIE in the nitrile-forming elimination of 467 (equation 275), promoted by Et3N-MeCN, t-BuOK-t-BuOH-and t-BuOK-DMSO, has been found533 to be dependent on the base-solvent variation from t-Bu-OH to DMSO. [Pg.1056]

With alkynes, the ferradisilacyclopentene and diferradisilacyclo-butane derivatives in entries 99 and 100 suffer cleavage of all or some of their Si-Fe bonds to yield cyclic and other products the former compound also reacts with nitriles, forming a novel heterocycle (XVI). [Pg.54]

Its solidification point is at 53°C the yield amounts to about 135 parts, that is, about 2/3 of the theoretical yield. When recrystallized from isopropyl alcohol the hydrochloride of the nitrile forms colorless crystals, readily soluble in water and melting at 221° to 222°C. [Pg.2158]

Palomo75 report that various aromatic aldehydes can be converted to nitriles in 94-97% yield by refluxing the aromatic aldehyde, hydroxylamine hydrochloride, and magnesium sulfate in toluene or xylene, with p-toluencsulfonic acid as catalyst for 1.5 to 3 hr. The microwave-assisted process may prove better for aliphatic aldehydes and may be made even more attractive if the above process conditions could be refined to reduce or eliminate NMP—for instance, if both aldehyde and nitrile form a homogeneous liquid at the reaction temperature. [Pg.362]

The participation of nitrilium salts has also been postulated42 in the Schmidt reaction and in some Beckmann rearrangements when concentrated sulfuric acid is employed. Hill43 has demonstrated recently that some Beckmann rearrangements carried out in a concentrated sulfuric acid medium are Ritter-type reactions in which the nitrile formed in situ from the oxime combines with a carbonium ion to yield a nitrilium salt, which, when diluted with water, leads to the N-alkylamide. [Pg.108]

Addition to nitriles.1 Reaction of Cp2Ti=CH2, readily formed from the ti-tanacyclobutane 1, with pivalonitrile forms the [2 + 2]cycloadduct a, which on further reaction with a nitrile forms eventually a new metallacycle 2. This product on acidolysis provides the ft-keto enamine 3. [Pg.79]

Methylisothiazole-5-carboxylic acid has also been prepared by alkaline hydrolysis of the 5-nitrile. The 5-acids decarboxylate readily at or near their melting points but otherwise behave normally, forming acid chlorides, esters, amides, hydra-zides, and nitriles. The esters undergo the Claisen condensation to form ]8-ketoesters, and the nitriles form thioamides with hydrogen sulfide in pyridine. An anomalous reaction is the reduction of 5-cyano-... [Pg.118]


See other pages where Nitrile-forming is mentioned: [Pg.118]    [Pg.97]    [Pg.10]    [Pg.361]    [Pg.146]    [Pg.147]    [Pg.385]    [Pg.141]    [Pg.397]    [Pg.143]    [Pg.151]    [Pg.264]    [Pg.1056]    [Pg.920]    [Pg.108]    [Pg.1099]    [Pg.306]    [Pg.65]   
See also in sourсe #XX -- [ Pg.97 , Pg.98 , Pg.99 , Pg.366 , Pg.397 , Pg.414 ]




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