Aldehydes with alcohols

Resins formed from the reaction of poly(vinyl alcohol) with aldehydes. The formal derivative (from methanal) is used in wire coatings and adhesives and the bulyral (from butanal) is used in metal paints, wood-sealers, adhesives and in safety glass interlayers. 

By the controlled oxidation of primary alcohols with a solution of potassium or sodium dichromate in dilute sulphuric acid. To avoid the further oxidation to the corresponding acid, the aldehyde is removed as rapidly as possible by distillation through a fractionating column, for example ... 

Aldehydes condense with alcohols in the presence of a catalyst (1-2-5 per... 

Extensive studies on the Wacker process have been carried out in industrial laboratories. Also, many papers on mechanistic and kinetic studies have been published[17-22]. Several interesting observations have been made in the oxidation of ethylene. Most important, it has been established that no incorporation of deuterium takes place by the reaction carried out in D2O, indicating that the hydride shift takes place and vinyl alcohol is not an intermediate[l,17]. The reaction is explained by oxypailadation of ethylene, / -elimination to give the vinyl alcohol 6, which complexes to H-PdCl, reinsertion of the coordinated vinyl alcohol with opposite regiochemistry to give 7, and aldehyde formation by the elimination of Pd—H. 

When allylic alcohols are used as an alkene component in the reaction with aryl halides, elimination of /3-hydrogen takes place from the oxygen-bearing carbon, and aldehydes or ketones are obtained, rather than y-arylated allylic alcohoIs[87,88]. The reaction of allyl alcohol with bromobenzene affords dihydrocinnamaldehyde. The reaction of methallyl alcohol (96) with aryl halides is a good synthetic method for dihydro-2-methylcinnamaldehyde (97). 

The slow oxidation of primary alcohols, particularly MeOH, is utilized for the oxidation of allylic or secondary alcohols with allyl methyl carbonate without forming carbonates of the alcohols to be oxidized. Allyl methyl carbonate (564) forms 7r-allylpalladium methoxide, then exchange of the methoxide with a secondary or allylic alcohol 563 present in the reaction medium takes place to form the 7r-allylpalladium alkoxide 565, which undergoes elimination of j3-hydrogen to give the ketone or aldehyde 566. The lactol 567 was oxidized selectively with diallyl carbonate to the lactone 568 without attacking the secondary alcohol in the synthesis of echinosporin[360]. 

In the reverse reaction, thioheteroaryl amides reacted under reflux in alcohol with haloketones or aldehydes to give the corresponding 2-heteroarylthiazole derivatives (238, 271, 482, 550, 751, 765, 776, 781). 2,2 -Bithiazoles (4,4 -disubstituted) have been obtained in 80 to 90% yield by cyclocondensation of 1 mole rubeanic acid with 2 moles of a-bromoketones in polyphosphoric acid at 95 to 135 C (780). Some multiheteroaryl substituted thiazoles have been also reported (704). 

Acetaldehyde [75-07-0] (ethanal), CH CHO, was first prepared by Scheele ia 1774, by the action of manganese dioxide [1313-13-9] and sulfuric acid [7664-93-9] on ethanol [64-17-5]. The stmcture of acetaldehyde was estabhshed in 1835 by Liebig from a pure sample prepared by oxidising ethyl alcohol with chromic acid. Liebig named the compound "aldehyde" from the Latin words translated as al(cohol) dehyd(rogenated). The formation of acetaldehyde by the addition of water [7732-18-5] to acetylene [74-86-2] was observed by Kutscherow] in 1881. 

Analogously, aldehydes react with ammonia [7664-41-7] or primary amines to form Schiff bases. Subsequent reduction produces a new amine. The addition of hydrogen cyanide [74-90-8] sodium bisulfite [7631-90-5] amines, alcohols, or thiols to the carbonyl group usually requires the presence of a catalyst to assist in reaching the desired equilibrium product. 

Aldehydes react with alkenylborates to give 1,3-diols upon oxidation of the intermediate (300). Alkynylborates ate transformed by epoxides into homoallyhc alcohols and alkenylborates into 1,4-diols (300,301). Carbon dioxide reacts with alkenylborates to yield catboxyhc acids (302). The scope of these transformations is further extended by the use of functionalized electrophiles and borates, often reacting with high stereoselectivity. For example, in the... 

A nitro alcohol is formed when an ahphatic nitro compound with a hydrogen atom on the nitro-bearing carbon atom reacts with an aldehyde in the presence of a base. Many such compounds have been synthesized, but only those formed by the condensation of formaldehyde (qv) and the lower nitroparaffins (qv) are marketed commercially. The condensation may occur one to three times, depending on the number of hydrogen atoms on the nitro-substituted carbon (R and R = H or alkyl), and yield nitro alcohols with one to three hydroxyl groups. 

Aldol reaction of campholenic aldehyde with propionic aldehyde yields the intermediate conjugated aldehyde, which can be selectively reduced to the saturated alcohol with a sandalwood odor. If the double bond in the cyclopentene ring is also reduced, the resulting product does not have a sandalwood odor (161). Reaction of campholenic aldehyde with -butyraldehyde followed by reduction of the aldehyde group gives the aHyUc alcohol known commercially by one manufacturer as Bacdanol [28219-61 -6] (82). 

Vinyllithium [917-57-7] can be formed direcdy from vinyl chloride by means of a lithium [7439-93-2] dispersion containing 2 wt % sodium [7440-23-5] at 0—10°C. This compound is a reactive intermediate for the formation of vinyl alcohols from aldehydes, vinyl ketones from organic acids, vinyl sulfides from disulfides, and monosubstituted alkenes from organic halides. It can also be converted to vinylcopper [37616-22-1] or divinylcopper lithium [22903-99-7], which can then be used to introduce a vinyl group stereoselectively into a variety of a, P-unsaturated systems (26), or simply add a vinyl group to other a, P-unsaturated compounds to give y, 5-unsaturated compounds. Vinyllithium reagents can also be converted to secondary alcohols with trialkylb o r ane s. 

One of the first practical methods for the manufacture of cinnamyl alcohol involved reduction of cinnamic aldehyde diacetate with iron filings in acetic acid. This approach suffered from low yields and Hberation of a significant amount of the starting aldehyde. 

Esters are most commonly prepared by the reaction of a carboxyHc acid and an alcohol with the elimination of water. Esters are also formed by a number of other reactions utilizing acid anhydrides, acid chlorides, amides, nitriles, unsaturated hydrocarbons, ethers, aldehydes, ketones, alcohols, and esters (via ester interchange). Detailed reviews of esterification are given in References 1—9. 

These reactions ate carried out in the presence of acidic and basic catalysts. The acid-cataly2ed addition of ethyl alcohol to acetylene or to a vinyl ether produces acetals (diethers of 1,1-dihydroxyethane). The acid-cataly2ed reaction of ethyl alcohol with an aldehyde or ketone also gives acetals. 

Treatment of poly(vinyl alcohol) with aldehydes and ketones leads to the formation of poly(vinyl acetals) and poly(vinyl ketals), of which only the former products are of any commercial significance Figure 14.7). 

Distillation is required to remove aldehyde, alcohol, and water which would react with the Grignard reagent in the next step. a,d-Dibromoethyl ethyl ether is also a lachrymator. 

Chromic acid (H2Cr04) is a good oxidizing agent and is fonned when solutions containing chromate (Cr04 ) or dichromate (Cr Oy ) are acidified. Sometimes it is possible to obtain aldehydes in satisfactory yield before they are further oxidized, but in most cases carboxylic acids are the major products isolated on treatment of primary alcohols with chromic acid. 

X0 to hydroxy compounds. Lower temperatures favor ketone formation and sterically hindered carbonyls, such as 2-thienyl t-butyl ketone, are not reduced. The sensitivity of desulfurization to steric factors is evident by the failure to desulfurize 2,5-di-i-butyl-3-acetylthiophene. The carbonyl groups of both aldehydes and ketones can be protected by acetal formation, as particularly cyclic acetals are stable during desulfurization in methanol at room temperature. " The free aldehydes give primary alcohols on desulfurization. Another method to obtain only keto compounds is to oxidize the mixtures of ketone and secondary alcohol with CrOs after the desulfurization. - Through the desulfurization of 5,5 -diacetyl-2,2, 5, 2"-terthienyl (228), 2,15-hexadecandione (229) has been obtained, which... 

In the case of the bases derived from quaternary heterocyclic ammonium salts, the carbinolamines (5) can react as cyclic aldehyde-ammonias with many reagents with which the amino-aldehyde (7) could react. However, reactions of the carbinolamines which are not characteristic of amino-aldehydes are also known. Carbinolamines can easily be reconverted into the quaternary salts by the action of dilute acids, and they form alkyl ethers very easily with alcohols. If these last reactions do not occur, then this is convincing evidence for the base possessing the amino-aldehyde structure. However, if these reactions do occur this does not provide unambiguous confirmation of the carbinolamine structure. They are also given by the bi-molecular ethers (8), and, in the case of a tautomeric equilibrium... 

Aldehydes are formed by the reduction of the ester of the corresponding acid to the alcohol, and then oxidising the alcohol with heated copper as catalyst. It is well known that when primary alcohols in the gaseous state are passed over finely-divided copper dust, obtained by reduction of copper oxide, at 250° to 400°, they yield hydrogen, and aldehydes or ketones respectively. 

Polyvinyl acetate and derivatives Polyvinyl acetate is used largely for coating applications, but the derivative polyvinyl alcohol, will, providing there are some residual acetate groups, dissolve in water. Reaction products of polyvinyl alcohol with aldehydes such as polyvinyl formal and polyvinyl butyral are highly specialised materials. 

As examples of their addition to carbonyl compounds, Grignard reagents react with formaldehyde, H2C = 0, to give primary alcohols, with aldehydes to give secondary alcohols, and with ketones to give tertiary alcohols. 

C ( propyl) N phenylmtrone to N phenylmaleimide, 46, 96 semicarbazide hydrochloride to ami noacetone hydiochlonde, 46,1 tetraphenylcyclopentadienone to diphenyl acetylene, 46, 44 Alcohols, synthesis of equatorial, 47, 19 Aldehydes, aromatic, synthesis of, 47, 1 /3-chloro a,0 unsaturated, from ke tones and dimethylformamide-phosphorus oxy chloride, 46, 20 from alky 1 halides, 47, 97 from oxidation of alcohols with dimethyl sulfoxide, dicyclohexyl carbodumide, and pyndimum tnfluoroacetate, 47, 27 Alkylation, of 2 carbomethoxycyclo pentanone with benzyl chloride 45,7... 

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