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Saturated Aliphatic Aldehydes

The carbonyl compounds that can undergo this condensation include aliphatic, aromatic, and <%,/ -unsaturated aldehydes, aliphatic, saturated carbo-cyclic, and aromatic ketones, diketones, oxo esters, and cyano ketones. Sodium ethoxide and potassium terf-butoxide are the condensing agents generally used. [Pg.986]

Composition. Shellac is primarily a mixture of aUphatic polyhydroxy acids in the form of lactones and esters. It has an acid number of ca 70, a saponification number of ca 230, a hydroxyl number of ca 260, and an iodine number of ca 15. Its average molecular weight is ca 1000. Shellac is a complex mixture, but some of its constituents have been identified. Aleuritic acid, an optically inactive 9,10,16-trihydroxypalmitic acid, has been isolated by saponification. Related carboxyflc acids such as 16-hydroxy- and 9,10-dihydroxypalmitic acids, also have been identified after saponification. These acids may not be primary products of hydrolysis, but may have been produced by the treatment. Studies show that shellac contains carboxyflc acids with long methylene chains, unsaturated esters, probably an aliphatic aldehyde, a saturated aliphatic ester, a primary alcohol, and isolated or unconjugated double bonds. [Pg.141]

Cinnamic Acid.—The reaction, which takes place when an aldehyde (aliphatic or aromatic) acts on the sodium salt of an aliphatic acid in presence of the anhychide, is known as Perkin s reaction, and has a ery wide application. Accoid-ing to the result of Fittig s researches on the properties of the unsaturated acids described below, the reaction occurs in two steps. The aldeh) de forms first an additive compound with the acid, the aldehyde caibon attaching itself to the n-carbon ii.e.i nevt the carbovyl) of the acid. A saturated hydiOKy-acid is formed, which is stable, if the a-carbon is attached to only one atom of hydrogen, as in the case of isobutync acid,... [Pg.304]

A method for the conversion of unsaturated aliphatic aldehydes to saturated aldehydes is a gentle catalytic hydrogenation. Palladium is more selective than nickel. Hydrogenation over sodium borohydride-reduced palladium in methanol at room temperature and 2 atm reduced crotonaldehyde to butyralde-hyde but did not hydrogenate butyraldehyde [57]. Nickel prepared by reduction with sodium borohydride was less selective it effected reduction of crotonaldehyde to butyraldehyde but also reduction of butyraldehyde to butyl alcohol, though at a slower rate [57]. Hydrogenation of 2,2,dimethyl-... [Pg.97]

Reduction of unsaturated aliphatic aldehydes to saturated alcohols was... [Pg.98]

Alcohols, amines, phenols, aliphatic saturated aldehydes, thioethers, ethers, fatty acid esters, hydrocarbons, aromatics, vinyl-type fluorori-nated, and those with one chlorine atom all give a low response. [Pg.308]

Z)-Allyltrimethylsilanes.1 Reaction of aldehydes with 2-trimethylsilylethy-lidinetriphenylphosphorane has been used to convert aldehydes into allyltrime-thylsilanes as a mixture of (E)- and (Z)-isomers (9,492). Replacement of triphen-ylphosphine by tris(2-methylphenyl)phosphine enhances (Z)-selectivity, particularly in reactions with aliphatic saturated aldehydes. These aldehydes can be converted into the (Z)-allylsilanes (Z/E > 94%) with 1, and with use of BuLi at 0° for generation of the phosphorane. [Pg.345]

The success of the method employing Li/MeNH2 again arises from the formation of the aldehyde in a protected form. In this case it is the amino alcohol salt (2 Scheme 2). As shown in Scheme 2, the reaction mixture is quenched with saturated aqueous ammonium chloride and may then be extracted with pentane, to yield an imine, or with ether and washed with acid to give the aldehyde. The imine is clearly not the protected form of the aldehyde, as it is reduced to the corresponding secondary amine under the conditions of the reaction. The reaction succeeds for aliphatic saturated acids, and also for one example... [Pg.284]

When a stream of ozonized oxygen or air, usually under 6% ozone, is passed through a solution of an olefin, such as 2,4,4-trimethyl-2-pentene, absorption occurs as fast as the ozone is introduced and no ozone escapes through the solution until all the olefin has been converted to ozonide. If an aromatic hydrocarbon such as benzene is ozonized rather than an aliphatic olefin, absorption of ozone is not complete and several times the theoretical amount of ozone must be used to effect complete ozoniza-tion. When a molecule has both an aromatic system and an aliphatic double bond, the aliphatic bond may react selectively, with little or no reaction with the aromatic system. Anethole will absorb a mole of ozone and produce, on hydrolysis of the ozonide, a very good yield of anise aldehyde. Complete saturation of the molecule requires almost 10 moles of ozone, however. [Pg.141]

Ill) Conjugated Aldehyde, Acid, Ester, Nitrile, Nitro Functions. Double bond hydrogenation of a,)3-unsaturated potentially reducible groups other than ketones is also possible. Aliphatic saturate aldehydes are obtained in high yields by reduction over Pd,... [Pg.179]

H.A-1, hydroxyacetaldehyde (glycolaldehyde), which is both an alcohol and aldehyde. The saturated aliphatic alcohols range from methanol to 1-triacontanol with alkyl homologs inclnded in some cases, for example, 1-butanol and 2-methyl-... [Pg.111]

Aldehydes are stoichiometrically decarbonylated by reaction with (XL) under mild conditions (77, 98,110,113). Aromatic aldehydes yield aromatic hydrocarbons whereas aliphatic aldehydes form saturated hydrocarbons and olefins. The latter minor products can be considered to arise from a reverse hydroformylation reaction. The initial step of this reaction is probably the oxidative addition of an aldehyde C—H bond to the rhodium(I) complex. However, a stable adduct of this type has not yet been reported. The driving force in these reactions is derived from the stability of the carbonyl (LXIX). [Pg.89]

In the Diels-Alder reaction with inverse electron demand, the overlap of the LUMO of the 1-oxa-l,3-butadiene with the HOMO of the dienophile is dominant. Since the electron-withdrawing group at the oxabutadiene at the 3-position lowers its LUMO dramatically, the cycloaddition as well as the condensation usually take place at room or slightly elevated temperature. There is actually no restriction for the aldehydes. Thus, aromatic, heteroaromatic, saturated aliphatic and unsaturated aliphatic aldehydes may be used. For example, a-oxocarbocylic esters or 1,2-dike-tones for instance have been employed as ketones. Furthermore, 1,3-dicarbonyl compounds cyclic and acyclic substances such as Meldmm s acid, barbituric acid and derivates, coumarins, any type of cycloalkane-1,3-dione, (1-ketoesters, and 1,3-diones as well as their phosphorus, nitrogen and sulfur analogues, can also be ap-... [Pg.161]

Although there are now several catalysts useful for hydrogenation of saturated carbonyl compounds to alcohols (see Section XII), an alternative approach has involved initial hydrosilylation (Chapter 9 in this volume) followed by acid hydrolysis [Eq. (41)]. The area first developed using principally the RhCl(PPh3)3 catalyst (207-210), and has since proved particularly useful in asymmetric syntheses (see Section III,A,4). Besides simple aliphatic and aromatic aldehydes and ketones, the ter-pene-ketones camphor and menthone were stereoselectively reduced to mainly the less stable alcohols e.g., camphor gave 9 (209). [Pg.337]

Oxidative attack on a carbon-hydrogen bond of an alkyl group a to a nitrogen atom is not restricted to saturated aliphatic amines. In fact X in an X-N-CH- structural subunit can be virtually any common atomic grouping that can be found in stable organic molecules. For example, w-carbon hydrogens of Aralkyl-substituted aromatic cyclic amines (119), aryl amines (120), amides (121), amidines (122), A-nitrosodialkylamines (123), etc. are all subject to oxidative attack, carbinolamine formation, and in most cases release of an aldehyde or ketone depending on the substitution pattern (1° or 2°)... [Pg.79]

In the 1970s, Brouwer and Kifflin reported the reactions of saturated hydrocarbons with aliphatic aldehydes and ketones in superacidic media. Analysis of the products from these reactions suggested that the protonated aldehydes and ketones (carboxonium ions) were reacting at the carbon-hydrogen o-bonds of the alkanes. This was a surprising observation because carboxonium... [Pg.157]

The secretion of the red hartebeest is characterized by its high aldehyde content. Of an estimated 100 detectable constituents, 25 are saturated and unsaturated aliphatic aldehydes [138]. Because the aldehydes are highly susceptible to autoxidation, the secretion could therefore only be used for shortterm territorial marking. On the other hand, the conversion of the aldehydes to carboxylic acids could also be transmitting information with a date stamp . In this regard, it is debatable whether fatty acids, which are almost ubiquitous in the animal world, really are such major carriers of semiochemical information in all of the many species in which they are purported to fulfill this role. [Pg.272]


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See also in sourсe #XX -- [ Pg.110 , Pg.111 , Pg.112 , Pg.113 , Pg.114 , Pg.115 ]




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Aliphatics aldehydes

Saturated Aliphatics

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