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Effects ketone

Aldehydes are more reactive than ketones. Two factors that make aldehydes more reactive than ketones are electronic and steric effects. Ketones have two alkyl groups, whereas aldehydes have only one. Because alkyl groups are electron donating, ketones have their effective partial positive charge reduced more than aldehydes. The electrophilic carbon is the site where the nucleophile approaches for reaction to occur. In ketones, two alkyl groups create more steric hindrance than one in aldehydes. As a result, ketones offer more steric resistance toward the nucleophilic attack than aldehydes. [Pg.88]

Platinum-alkylperoxo and -hydroperoxo complexes are much less effective ketonization reagents than their palladium analogs. The platinum-hydroperoxide complex generated by protonation of Pt(PPh3)202 as in equation (90) was found to be inactive,133 as well as Pt(CF3)(OOH)(depe) obtained from the reaction of H202 with the corresponding hydroxo complex.265... [Pg.349]

This phenomenon has been termed oxygenated Fenton chemistry. It has also been observed with [Co (bpy)2 ] in 4 1 MeCN/py, which effects ketonization of the methylenic centers of cyclohexane, cyclohexene and... [Pg.309]

The sample to be analyzed can be dissolved in an organic solvent, xylene or methylisobutyl ketone. Generally, for reasons of reproducibility and because of matrix effects (the surroundings affect the droplet size and therefore the effectiveness of the nebulization process), it is preferable to mineralize the sample in H2SO4, evaporate it and conduct the test in an aqueous environment. [Pg.34]

Iron(III) chloride forms numerous addition compounds, especially with organic molecules which contain donor atoms, for example ethers, alcohols, aldehydes, ketones and amines. Anhydrous iron(III) chloride is soluble in, for example, ether, and can be extracted into this solvent from water the extraction is more effective in presence of chloride ion. Of other iron(III) halides, iron(III) bromide and iron(III) iodide decompose rather readily into the +2 halide and halogen. [Pg.394]

Reagent A is particularly useful for the treatment of the lower aliphatic aldehydes and ketones which are soluble in water cf. acetaldehyde, p. 342 acetone, p. 346). The Recent is a very dilute solution of the dinitrophenylhydrazine, and therefore is used more to detect the presence of a carbonyl group in a compound than to isolate sufficient of the hydrazone for effective recrystallisation and melting-point determination. [Pg.263]

Metallic sodium. This metal is employed for the drying of ethers and of saturated and aromatic hydrocarbons. The bulk of the water should first be removed from the liquid or solution by a preliminary drying with anhydrous calcium chloride or magnesium sulphate. Sodium is most effective in the form of fine wire, which is forced directly into the liquid by means of a sodium press (see under Ether, Section II,47,i) a large surface is thus presented to the liquid. It cannot be used for any compound with which it reacts or which is affected by alkalis or is easily subject to reduction (due to the hydrogen evolved during the dehydration), viz., alcohols, acids, esters, organic halides, ketones, aldehydes, and some amines. [Pg.143]

These substances, as well as the parent compound, are p-keto esters and undergo hydrol3rtio cleavage in two directions. One type of cleavage, ketonlc hydrolysis, is effected by the action of dilute caustic alkali in the cold, followed by acidification and boiling the free acetoacetic acid produced has a carboxyl and carbonyl group on the same carbon atom and therefore readily undergoes decarboxylation to yield a ketone, for example ... [Pg.475]

The formation of ethyl isopropylidene cyanoacetate is an example of the Knoevenagel reaction (see Discussion before Section IV,123). With higher ketones a mixture of ammonium acetate and acetic acid is an effective catalyst the water formed is removed by azeotropic distillation with benzene. The essential step in the reaction with aqueous potassium cyanide is the addition of the cyanide ion to the p-end of the ap-double bond ... [Pg.490]

The commercial product, m.p. 53-55°, may be used. Alternatively the methyl -naphthyl ketone may be prepared from naphthalene as described in Section IV,136. The Friedel - Crafts reaction in nitrobenzene solution yields about 90 per cent, of the p-ketone and 10 per cent, of the a-ketone in carbon disulphide solution at — 15°, the proportions ore 65 per cent, of the a- and 35 per cent, of the p-isomer. With chlorobenzene ns the reaction medium, a high proportion of the a-ketone is also formed. Separation of the liquid a-isomer from the solid p-isomer in Such mixtures (which remain liquid at the ordinary temp>erature) is readily effected through the picrates the picrate of the liquid a-aceto compound is less soluble and the higher melting. [Pg.767]

The acylation of ketones with acid anhydrides may be effected by means of the acid reagent boron trifluoride, for example ... [Pg.861]

The acylation of ketones with esters an example of the Clalsen condensation is generally effected with a basic reagent, such as sodium ethoxide, sodium, sodamide or sodium hy dride. Thus acetone and ethyl acetate condense in the presence of sodium ethoxide to yield acetylacetone ... [Pg.861]

It may be mentioned that the condensation in the presence of metallic sodium appears to be partly effected by the metal which displaces atomic hj drogen from the ketone ... [Pg.862]

Tire results of a study of the effect of these catalysts on the model Diels-Alder reaction of methyl vinyl ketone (4.8) with cyclopentadiene (4.6) are summarised in Table 4.1... [Pg.109]

These are effective high-octane gasoline additive oxygenates. The conversion of isobutane into isopropyl, methyl ketone, or isopentane into isobutyl, methyl ketone is illustrative. In this reaction, no branched carboxylic acids (Koch products) are formed. [Pg.166]

Well, that s about as rounded an education on Leuckart reactions as Strike can give. Strike feels that after reading all of those similar, repetitious steps, one can start to get a good feel for where a product is at any given moment. Stuff like what happens to MDA when it s mixed with acid or base, or what happens to ketones (P2P) under the same circumstances. One can see now that it is possible to not only isolate safrole and P2Ps chemically but that the same can be true for the final MDA or meth freebase oil. Repeated washings with acid or base and solvent can effectively clean up a compound to an almost presentable state without the use of vacuum distillation, it can happen, one only needs have confidence in the chemistry. [Pg.116]

The ketone is added to a large excess of a strong base at low temperature, usually LDA in THF at -78 °C. The more acidic and less sterically hindered proton is removed in a kineti-cally controlled reaction. The equilibrium with a thermodynamically more stable enolate (generally the one which is more stabilized by substituents) is only reached very slowly (H.O. House, 1977), and the kinetic enolates may be trapped and isolated as silyl enol ethers (J.K. Rasmussen, 1977 H.O. House, 1969). If, on the other hand, a weak acid is added to the solution, e.g. an excess of the non-ionized ketone or a non-nucleophilic alcohol such as cert-butanol, then the tautomeric enolate is preferentially formed (stabilized mostly by hyperconjugation effects). The rate of approach to equilibrium is particularly slow with lithium as the counterion and much faster with potassium or sodium. [Pg.11]

The carbopalladation of allylamine with malonate affords the chelating complex 510, which undergoes insertion of methyl vinyl ketone to form the amino enone 511[463]. The allylic sulfide 512 has the same chelating effect to give the five-membered complex 513 by carbopalladation[463.464]. [Pg.95]


See other pages where Effects ketone is mentioned: [Pg.199]    [Pg.155]    [Pg.1164]    [Pg.1164]    [Pg.56]    [Pg.639]    [Pg.388]    [Pg.450]    [Pg.106]    [Pg.209]    [Pg.199]    [Pg.155]    [Pg.1164]    [Pg.1164]    [Pg.56]    [Pg.639]    [Pg.388]    [Pg.450]    [Pg.106]    [Pg.209]    [Pg.258]    [Pg.285]    [Pg.419]    [Pg.2593]    [Pg.172]    [Pg.1061]    [Pg.9]    [Pg.6]    [Pg.23]    [Pg.26]    [Pg.45]    [Pg.48]    [Pg.107]    [Pg.109]    [Pg.169]    [Pg.60]    [Pg.136]    [Pg.504]    [Pg.53]   
See also in sourсe #XX -- [ Pg.294 ]




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A-Halo ketone effect

Effective ligands for iron-catalyzed ketone and imine reduction

Effects of Conjugation in a,(3-Unsaturated Aldehydes and Ketones

Fluorinated ketones, effect

Halo Ketone Effect

Hydrogen abstraction, ketones conformational effects

Hydrogen abstraction, ketones solvent effects

Hydrogen abstraction, ketones substituent effects

Inductive effect in aldehydes and ketones

Ketone cage effects

Ketone polymers crystallinity effects

Ketone polymers glass transition temperature effects

Ketones acid effect

Ketones base effect

Ketones catalyst effect

Ketones conjugation effects

Ketones effect of base

Ketones electrostatic effects

Ketones polar effects

Ketones resonance effects

Ketones ring size effects

Ketones selective, solvent effect

Ketones solvent effect

Ketones steric effects

Ketones, halogenation electronic effects

Methyl ethyl ketone health effects

Pressure effect, methyl ethyl ketone

Solvent effect unsaturated ketones

Stereochemistry ketones, acid effect

Stereochemistry ketones, base effect

Stereochemistry ketones, solvent effect

Stereoelectronic effects ketones

Steric effects in hydration of aldehydes and ketones

Steric effects on kinetic acidity of ketones

Substituent effects aldehydes and ketones

Substituent effects ketones

Substituent effects of aldehydes and ketones

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