Hydroxy carbonylations

Supplement (combined with Volume IV) 1942 195-449 Carbonyl-carboxylic acids Glyoxalic acid, 504. Acetoacotic acid, 630. Hydroxy-carbonyl carboxylic acids Glycuronic acid, 883. 

Supplement 1942 195-449 Hydroxy-amines Aminoethyl alcohol, 274. Carbonyl-amines Aminoacetaldehyde, 307. Aminoacetone, 314. Hydroxy-carbonyl amines Glucosamine, 328. Aminocarboxylic acids Glycine, 333. Hydroxylamines, 534. Hydrazines, 546. Azo Compounds. 562. Oryano-metallic Compounds, 580. 

Supplement 1950 1505-1591a acid, 269. Hydroxy-carbonyl sulphonic acids Camphor-sulphonio acid, 345. Carboxylic-sulphonic acids, 368. Se and Te acids, 422. 

Supplement 1951 1872-1928 Hydroxy-carbonyl amines, 233. Amino-carboxylic acids Anthranilic acid (o-aminobenzoicacid). 310. Amino-hydroxy-carboxylic acids, 577. Amino-sulphonic acids Sulphanilio acid, 695. 

XXV XXV, 1st 1936 3634-3793 Two Cyclic Nitrogens (continued). 1 Hydroxy-carbonyl compounds, 1 1... 

Synthesis The synthesis uses rather more vigorous conditions than those which gave the p-hydroxy carbonyl compoimds. In fact tBull. Chem. Japan. 1952, 25, 54, Chem. Abs..l954. 48. 5143) you can either treat the p-hydroxy compoimd with HCl in acetic acid or do the condensation in base ... 

Aldol additions and ester condensations have always been and still are the most popular reactions for the formation of carbon-carbon bonds (A.T. Nielsen, 1968). The earbonyl group acts as an a -synthon, the enoi or enolate as a d -synthon. Both reactions will be treated together here, and arguments, which are given for aldol additions, are also valid for ester condensations. Many famous name reactions belong to this category ). The products of aldol additions may be either /J-hydroxy carbonyl compounds or, after dehydration, or, -unsaturated carbonyl compounds. 

Cleavage reactions of carbohydrates also occur on treatment with aqueous base for prolonged periods as a consequence of base catalyzed retro aldol reactions As pointed out m Section 18 9 aldol addition is a reversible process and (3 hydroxy carbonyl com pounds can be cleaved to an enolate and either an aldehyde or a ketone... 

Vicinal diol and a hydroxy carbonyl functions in carbohydrates are cleaved by periodic acid Used analytically as a tool for structure determination... 

The flavone, isoflavone, and flavonol-type dyes owe their importance to the presence of an o-hydroxy carbonyl stmcture within the molecule. Positions 4 and 5 can chelate with different metallic salts to give colored, insoluble complexes. In other words, these dyes require a mordant in order to fix them onto the fiber. Perkin was able to predict the stmcture of unknown flavones by comparing the color of their complexes with the color of known complexes (70). For example, ferric chloride gives a green color with 5-hydroxyflavones and a brown one with 3-hydroxyflavones (71). 

The study of acid-base interaction is an important branch of interfacial science. These interactions are widely exploited in several practical applications such as adhesion and adsorption processes. Most of the current studies in this area are based on calorimetric studies or wetting measurements or peel test measurements. While these studies have been instrumental in the understanding of these interfacial interactions, to a certain extent the interpretation of the results of these studies has been largely empirical. The recent advances in the theory and experiments of contact mechanics could be potentially employed to better understand and measure the molecular level acid-base interactions. One of the following two experimental procedures could be utilized (1) Polymers with different levels of acidic and basic chemical constitution can be coated on to elastomeric caps, as described in Section 4.2.1, and the adhesion between these layers can be measured using the JKR technique and Eqs. 11 or 30 as appropriate. For example, poly(p-amino styrene) and poly(p-hydroxy carbonyl styrene) can be coated on to PDMS-ox, and be used as acidic and basic surfaces, respectively, to study the acid-base interactions. (2) Another approach is to graft acidic or basic macromers onto a weakly crosslinked polyisoprene or polybutadiene elastomeric networks, and use these elastomeric networks in the JKR studies as described in Section 4.2.1. 

Reaction of aldehydes or ketones to give /3-hydroxy carbonyl compounds... 

If the initially formed /3-hydroxy carbonyl compound 3 still has an a-hydrogen, a subsequent elimination of water can take place, leading to an o ,/3-unsaturated aldehyde or ketone 4. In some cases the dehydration occurs already under the aldol reaction conditions in general it can be carried out by heating in the presence of acid ... 

An alkene activated by an electron-withdrawing group—often an acrylic ester 2 is used—can react with an aldehyde or ketone 1 in the presence of catalytic amounts of a tertiary amine, to yield an a-hydroxyalkylated product. This reaction, known as the Baylis-Hillman reaction, leads to the formation of useful multifunctional products, e.g. o -methylene-/3-hydroxy carbonyl compounds 3 with a chiral carbon center and various options for consecutive reactions. 

All three elimination reactions--E2, El, and ElcB—occur in biological pathways, but the ElcB mechanism is particularly common. The substrate is usually an alcohol, and the H atom removed is usually adjacent to a carbonyl group, just as in laboratory reactions. Thus, 3-hydroxy carbonyl compounds are frequently converted to unsaturated carbonyl compounds by elimination reactions. A typical example occurs during the biosynthesis of fats when a 3-hydroxybutyryl thioester is dehydrated to the corresponding unsaturated (crotonyl) thioester. The base in this reaction is a histidine amino acid in the enzyme, and loss of the OH group is assisted by simultaneous protonation. 

The product is a jS-hydroxy carbonyl compound. Sign in atwwvu.thomsonedu.com to see a simulation based on this figure and to take a short quiz. 

The reaction conditions needed for aldol dehydration are often only a bit more vigorous (slightly higher temperature, for instance) than the conditions needed for the aldol formation itself. As a result, conjugated enones are usually obtained directly from aldol reactions without isolating the intermediate jS-hydroxy carbonyl compounds. 

StepS 9-1° of F Sure 29-7 Dehydration and Dephosphorylation Like mos /3-hydroxy carbonyl compounds produced in aldol reactions, 2-phospho glvcerate undergoes a ready dehydration in step 9 by an ElcB mechanism (Section 23.3). The process is catalyzed by enolase, and the product i... 

Aldol reaction (Section 23.1) The carbonyl condensation reaction of an aldehyde or ketone to give a jS-hydroxy carbonyl compound. 

Da cyclische Halbacetale (Lactole) mit den Hydroxy-aldehyden bzw. Hydroxy-ke-tonen im Gleichgewicht stehen, hangt ihre Reduzierbarkeit durch komplexe Metallhy-dride davon ab, wie weit dieses in Richtung zur offenkettigen Hydroxy-carbonyl-Verbin-dung verschoben ist, da nur letztere reduziert wird1 ... 

Write disconnections and starting materials forthi.> i-hydroxy carbonyl compounds. 

A range of transformation products has been identified from simulated reactions of alkanes. These include alkyl nitrates by reactions that have already been given, but also include a range of hydroxy-carbonyls that are summarized in Table 1.2 (Reisen et al. 2005). 

Supplement 1941 1-161 Derivatives. Methyl alcohol, 273. Ethyl alcohol, 292. Ethyl ether, 314. Glycerol, 502. Carbonyl Compounds Aldehydes, Ketones, Ketencs and Derivatives. Formaldehyde, 558. Acetaldehyde, 635. Acetone, 635. Ketene, 724. Hydroxy-Carbonyl Compounds Aldehyde-Alcohols, Ketone-Alcohols, Monosaccharides and Derivatives. Glycolaldehyde, 817. Aldol, 824. Pentoses, 858. Hexoses, 878. 

Edens GJ, Hamelin A, Weaver MJ. 1996. Mechanism of carbon monoxide electrooxidation on monocrystalline gold surfaces Identification of a hydroxy carbonyl intermediate. J Phys Chem 100 2322-2329. 

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