Hydroxyacetals

Guella, G. Mancini, I. Ehihet, D. Richer de Forges, B. Pietra, F. (1989B) Ethyl 6-bromo-3-indolcarboxylate and 3-hydroxyacetal-6-bromoindole, novel bromoindoles from the sponge Pleroma menoui of the Coral Sea. Z. Naturforsch., C Biosci., 44c, 914-6. 

Although 3-keto esters such as acetoacetate 46 or benzoylacetate did not give enantioselec-tivity better than 70% ee with DIOP-Rh catalysts [40], 2,2-dimethylacetoacetate 47 was reduced with 2 using a TRAP-Rh catalyst to give the corresponding 3-hydroxyacetate with 93% ee (5) at -30°C [271. 

Manufacture, Processing, and Economic Aspects. Hydroxyacetic acid is produced commercially in the United States as an iatermediate by the reaction of formaldehyde with carbon monoxide and water. 

Apart from lactic and hydroxyacetic acids, other a- and P-hydroxy acids have been small-volume specialty products produced in a variety of methods for specialized uses. y-Butyrolactone [96 8-0] which is the monomeric inner ester of y-hydroxybutyric acid [591-81-17, is a large-volume chemical derived from 1,4-butanediol (see Acetylene-derived chemicals). 

Reactions and Uses. The common reactions that a-hydroxy acids undergo such as self- or bimolecular esterification to oligomers or cycHc esters, hydrogenation, oxidation, etc, have been discussed in connection with lactic and hydroxyacetic acid. A reaction that is of value for the synthesis of higher aldehydes is decarbonylation under boiling sulfuric acid with loss of water. Since one carbon atom is lost in the process, the series of reactions may be used for stepwise degradation of a carbon chain. 

Contaminants and by-products which are usually present in 2- and 4-aminophenol made by catalytic reduction can be reduced or even removed completely by a variety of procedures. These include treatment with 2-propanol (74), with aUphatic, cycloaUphatic, or aromatic ketones (75), with aromatic amines (76), with toluene or low mass alkyl acetates (77), or with phosphoric acid, hydroxyacetic acid, hydroxypropionic acid, or citric acid (78). In addition, purity may be enhanced by extraction with methylene chloride, chloroform (79), or nitrobenzene (80). 

Glycolic (a-hydroxyacetic) acid [79-14-1J M 76.1, m 81", pK 3.62. Crystd from diethyl ether. 

In order to enhance the oral bioavailability of oximonam (104), a prodrug has been made by esterification of the carboxyl group with the t-butyl ester of hydroxyacetic acid (105). The product is prodrug gloximonam (106) [31], Gloximonam is efficiently converted to oximonam in the body by metabolic processes. 

Ozyessigsaure, /. hydroxyacetic acid. Oxyfettsaure,/. hydroxy fatty acid, ozygenieren, v.t. oxygenate, oxygenize, Ozygenierung, /. oxygenation. 

N-tert-butyl-2-(5-benzyloxy-6-hydroxymethyl-2-pyridyl )-2-hydroxyacet amide... 

Hyfor hydroxyacetic acid (glycollic acid)/formic acid... 

Hydroxy-L-prolin is converted into a 2-methoxypyrrolidine. This can be used as a valuable chiral building block to prepare optically active 2-substituted pyrrolidines (2-allyl, 2-cyano, 2-phosphono) with different nucleophiles and employing TiQ as Lewis acid (Eq. 21) [286]. Using these latent A -acylimmonium cations (Eq. 22) [287] (Table 9, No. 31), 2-(pyrimidin-l-yl)-2-amino acids [288], and 5-fluorouracil derivatives [289] have been prepared. For the synthesis of p-lactams a 4-acetoxyazetidinone, prepared by non-Kolbe electrolysis of the corresponding 4-carboxy derivative (Eq. 23) [290], proved to be a valuable intermediate. 0-Benzoylated a-hydroxyacetic acids are decarboxylated in methanol to mixed acylals [291]. By reaction of the intermediate cation, with the carboxylic acid used as precursor, esters are obtained in acetonitrile (Eq. 24) [292] and surprisingly also in methanol as solvent (Table 9, No. 32). Hydroxy compounds are formed by decarboxylation in water or in dimethyl sulfoxide (Table 9, Nos. 34, 35). 

An attempt to measure the IR spectrum of the hydroxy carbene [28] after UV photolysis (A>220 nm) of formaldehyde isolated in an argon matrix was unsuccessful (Sodeau and Lee, 1978). Instead of [28] only hydroxyacetal-dehyde resulting from carbene insertion into the C—H bond of the starting formaldehyde was found in the reaction products. Due to its small size, the... 

A low-molecular-weight condensation product of hydroxyacetic acid with itself or compounds containing other hydroxy acid, carboxylic acid, or hydroxy-carboxylic acid moieties has been suggested as a fluid loss additive [164]. Production methods of the polymer have been described. The reaction products are ground to 0.1 to 1500 p particle size. The condensation product can be used as a fluid loss material in a hydraulic fracturing process in which the fracturing fluid comprises a hydrolyzable, aqueous gel. The hydroxyacetic acid condensation product hydrolyzes at formation conditions to provide hydroxyacetic acid, which breaks the aqueous gel autocatalytically and eventually provides the restored formation permeability without the need for the separate addition of a gel breaker [315-317,329]. 

Hydroxyacetic acid, low-molecular-weight condensation product [164]... 

Rearrangement of trivalent (5-hexenyl)Co(salen) proceeds via a radical chain process leading to the isomeric cyclopentylmethyl complex.1387 The efficiency with which this rearrangement occurs is dependent on the presence of trace impurities or 02. The selective reaction of alcohols (ROH) with arylglyoxals (ArCOCHO) to give a-aryl-a-hydroxyacetic esters ArCH(0H)C02R is catalyzed by compounds of this family.1388... 

The achiral hydroxyacetic acid molecule versus the chiral lactic acid molecule ... 

Hydroxyacetic acid has a plane of symmetry that makes one side of the molecule a mirror image of the other side. 

Diphenyl-2-hydroxyacetic Acid 2,2/-(Ethylenedithio)diethanol 2,2/-Ethyliminodiethanol 2,2/-Iminodiethanol 2,2/-Thiodiethanethiol... 

AT-Hydroxyacetamide, 14 127 4-Hydroxyacetanilide, 2 670 physical properties of, 2 666t Hydroxyacetic acid, 14 126-130 applications for, 14 128-129 grades of, 14 128 production of, 14 127-128 Hydroxy acids, achiral derivatizing agents, 6 96t... 

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