Glyoxylate salt

C). When the infiltrated PMMA template composite is heated, mixed metal nitrates oxidize ethylene glycol to form mixed metal glyoxylate solid in the voids at a temperature lower than Tg of PMMA (about 100 °C) [41,77,78]. Further calcination removes the polymer template and causes the conversion of glyoxylate salt into LaFeOs [41,65,73]. 

Glycohc acid also undergoes reduction or hydrogenation with certain metals to form acetic acid, and oxidation by hydrogen peroxide ia the presence of ferrous salts to form glyoxylic acid [298-12A], HCOCOOH, and ia the presence of ferric salts ia neutral solution to form oxaHc acid, HOOCCOOH formic acid, HCOOH and Hberate CO2 and H2O. These reduction and oxidation reactions are not commercially significant. 

C-Disaccharide analogs of trehalose were recently [20c] prepared by using as a key step an aqueous Diels-Alder reaction between the sodium salt of glyoxylic acid and the water soluble homochiral glucopyranosil-l,3-pentadiene 19 (Equation 6.1). A mixture of four diastereoisomers in a 41 24 21 14 proportion was obtained after esterification with methanol and acetylation. The main diaster-eoisomer 20 was isolated and characterized as benzoyl-derivative. 

Iminium ions bearing an electron-withdrawing group bonded to the sp carbon of the iminium function are very reactive dienophiles. Thus, iminium ions 26 generated from phenylglyoxal (Scheme 6.15, R = Ph) or pyruvic aldehyde (R = Me) with methylamine hydrochloride, react with cyclopenta-diene in water at room temperature with good diastereoselectivity [25] (Scheme 6.15). If glyoxylic acid is used, the formation of iminium salt requires the free amine rather than the amine hydrochloride. 

The cycloaddition of glyoxylic acid with cyclopentadiene in water at pH 6 and 60 °C is slow and occurs with low yield and low diastereoselectivity [18] (Scheme 6.17). Proton (pH = 0.9) [18], copper salts [27] and Bi(OTf)3 [28] accelerate the reaction and increase the diastereoselectivity. The lactones 28 and 29 originate from endo and exo cycloadducts 27, respectively. The proposed rearrangement is depicted in Scheme 6.17 for the major endo adduct 30. A competitive ene reaction that originates 28 and 29 cannot be excluded [28]. 

This mechanism is supported by the fact that a secondary hydrazone such as (8) yields the azohydrazone (9) rather than the formazan.8 Ketone hydrazones also yield azohydrazones. The coupling of hydrazones of glyoxylic acid (10) with diazonium salts is accompanied by decarboxylation to yield 3-unsubstituted formazans (11). Similarly, hydrazones of mesoxalic acid (12) yield formazans with a carboxyl group in position 3, e.g., 13 (Scheme 2).910 Both 11 and 13 can react with diazonium salts to yield the... 

Petasis reported an efficient addition of vinyl boronic acid to iminium salts.92 While no reaction was observed when acetonitrile was used as solvent, the reaction went smoothly in water to give allyl amines (Eq. 11.54). The reaction of the boron reagent with iminium ions generated from glyoxylic acid and amines affords novel a-amino acids (Eq. 11.55). Carboalumination of alkynes in the presence of catalytic Cp2ZrCl2 and H2O affords vinylalane intermediates, which serve as nucleophiles in the subsequent addition to enantiomerically enriched... 

Ito et al.40 examined the electrochemical reduction of C02 in dimethylsulfoxide (DMSO) with tetraalkylammonium salts at Pb, In, Zn, and Sn under high C02 pressures. At a Pb electrode, the main product was oxalic acid with additional products such as tartaric, malonic, glycolic, propionic, and n-butyric acids, while at In, Zn, and Sn electrodes, the yields of these products were very low (Table 3), and carbon monoxide was verified to be the main product even at a Pt electrode, CO was mainly produced in nonaqueous solvents such as acetonitrile and DMF.41 Also, the products in propylene carbonate42 were oxalic acid at Pb, CO at Sn and In, and substantial amounts of oxalic acid, glyoxylic acid, and CO at Zn, indicating again that the reduction products of C02 depend on the electrode materials used. 

CASRN 94-74-6 molecular formula CgffgClOs FW 200.63 Biological. Cell-free extracts isolated from Pseudomonas sp. in a basal salt medium degraded MCPA to 4-chloro-o cresol and glyoxylic acid (Gamar and Gaunt, 1971). 

Es-Safi, N.E. et ah. Structure of a new xanthylium salt derivative. Tetrahedron Lett. 40, 5869,1999. Es-Safi, N.E. et ah, 2D NMR analysis for unambiguous structural elucidation of phenolic compounds formed through reaction between (-l-)-catechin and glyoxylic acid. Magn. Reson. Chem. 40, 693, 2002. 

From Catechol. Several routes have recently been developed for the synthesis of heliotropin from catechol. In one such route, catechol is converted into 3,4-dihydroxymandelic acid with glyoxylic acid in an alkaline medium in the presence of aluminum oxide. 3,4-Dihydroxymandelic acid is oxidized to the corresponding keto acid (e.g. with copper-(II) oxide), which is decarboxylated to 3,4-dihydroxybenzaldehyde [176]. The latter product is converted into heliotropin, for example, by reaction with methylene chloride in the presence of quaternary ammonium salts [177]. 

Access to racemic thiazolidine-2-carboxylic acid (3-thiaproline, 12) is obtained by reacting cysteamine (49) with glyoxylic acid ester (Scheme 9), 165>182>1831 whilst the reaction of (R)-cysteine with glyoxylic acid 184 1851 leads to (2/ /S,5/ )-thiazolidine-2-carboxylic acid. 185 The diastereomers of thiazolidine-2-carboxylic add (12) are rapidly interconverting and therefore cannot be separated. 185 In the presence of (2R,3R)- and (2S,3S)-tartaric acid, reaction of cysteamine with glyoxylic acid leads to the enantiomerically pure (2/ )- and (2S)-thia-zolidine-2-carboxylic acid salts. 186 The acids undergo fast racemization in acetic acid. 186 ... 

Water-soluble biodegradable polycarboxylates with an acetal or ketal weak link were inventions of Monsanto scientists in the course of their search for biodegradable deteigent polymers. However, the polymers were prevented by economics from reaching commercial status. The polymers are based on the anionic or cationic polymerization of glyoxylic esters at low temperature (molecular weight is inversely proportional to the polymerization temperature) and subsequent hydrolysis to the salt form of the polyacid, which is a hemiacetal (R = H) or ketal (R = CH3) if methylglyoxylic acid is used, and stable under basic conditions. 

In view of the quantities of benzene (CAUTION) required, the entire preparation must be carried out in the fume cupboard. Place a mixture of 125 ml of pure benzene and 32.5 g (0.123 mol) of dibutyl ( + )-tartrate (1) in a 500-ml threenecked flask, equipped with a Hershberg stirrer (Fig. 2.49) and a thermometer. Stir the mixture rapidly and add 58 g (0.13 mol) of lead tetraacetate (Section 4.2.45, p. 441) in small portions over a period of 20 minutes while maintaining the temperature below 30 °C by occasional cooling with cold water. Continue the stirring for a further 60 minutes. Separate the salts by suction filtration and wash with two 25 ml portions of benzene. Remove the benzene and acetic acid from the filtrate by flash distillation and distil the residue under diminished pressure, preferably in a slow stream of nitrogen. Collect the butyl glyoxylate (2) at 66-69 °C/5mmHg. The yield is 26g (81%). 

However, the synthesis is inferior to the processes based on phenols and glyoxylic acid. One reason is the large amount of waste salts which are inevitably produced. Reductive dehalogenation has been used for the synthesis of antibiotics... 

This was one of the first classes of catalyzed reactions that were shown to give rise to strong asymmetric amplifications (vide supra, Scheme 9).33 Many subsequent studies have been performed with variations in the structure of the chiral catalyst, generated from BINOL and titanium salts.50-52 Asymmetric amplification is frequently observed with these catalysts in the glyoxylate-ene reaction (Table 5). 

Derivatives of Formaldehyde and Acetaldehyde.—According to Tafel and Pfeffermann,1 the phenylhydrazones of aldehydes are readily converted into amines by reduction in sulphuric-acid solution at a lead cathode. Thus ethylidene phenyl-hydrazine yields about 60% of the theoretical percentage of pure ethylamine salt. The decomposition of glyoxime is more complicated. Besides ammonia and glyoxal and a small quantity of an acid (glyoxylic acid ) there is formed as the principal product the crystalline sulphate of a base, C2H802N2, the nature of which could not be determined with certainty. Ethylenediamine is not formed. Nor was a diamine obtained from methylglyoxime. 

However, excellent simple (exo endo = 95 5) and induced diastereoselectivity (94 6) was obtained by Jurczak [88] by applying the bornane sulfone amide derivative of glyoxylic acid 2-23 in the presence of a catalytic amount of a europium salt. Reaction of 2-23 with 1-methoxy-1,3-butadiene 2-24 gave predominantly 2-25 a which was transformed into the lactone 2-26 aiming towards the synthesis of compactin (Fig. 2-7)[89]. 

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