Carboxylic acids definition

Classification Aliphatic carboxylic acid Definition Distilled from roots of Valeriana officinalis Empirical C5H10O2 Formula CH3(CH2)3COOH... 

Classification Nonaromatic carboxylic acid Definition Acids having two hydrogen atoms replaceable by a metal Properties Dens. 1.020 m.p. 85-95 C Toxicology Irritating to eyes, skin, respiratory system TSCA listed... 

Classification Nonaromatic carboxylic acid Definition The commercial prod, is the L(+)-enantiomer Empirical C4H6O6... 

CAS 109-52-4 EINECS/ELINCS 203-677-2 UN 1760 FEMA 3101 Synonyms Butanecarboxylic acid 1-Butanecarboxylic acid Carboxylic acid C Pentanoic acid n-Pentanoic acid Propylacetic acid Valerianic acid Valeric acid Classification Aliphatic carboxylic acid Definition Distilled from roots of Valeriana officinalis... 

Formula C,8H37(OCH2CH2)nOCH2COOH, avg. n = 5 Uses Emulsifier, surfactant in cosmetics Manuf./Distrib. Somerset Cosmetic Co. Variati lso teareth-11 carboxylic acid Synonyms PEG-11 isosteatyl ether carboxylic acid Definition Carboxylic add of ethoxylated isostearyl alcohol Empirical C4<,H8oO,3... 

Synonyms Lysine, mono4-thiazolidinecarboxylate 1,3-Thiazolidine4-carboxylic acid Thiazolidine4-carboxylic acid Definition Lysine salt of thiazolidine carboxylic acid Empirical C4H2NO2S Properties M.w. 133.17 Uses Surfactant in cosmetics ManufUDistrib. AK Scientific MP Biomedicals Variati LysolecKhin... 

Take two test-tubes A and B in A place about 5 ml. of neutralised tartaric acid solution and in B place 5 ml. of distilled water. To each solution add 3-4 drops of ferric chloride solution. Place a piece of white paper under the tubes, look down their length and note that A is definitely yellow compared with the control tube B. This yellow colour is given by a-hydroxy-carboxylic-acids, lactic acid, tartaric acid, citric acid. 

In this definition ko is the rate constant for CH3COOR and k is the constant for RCOOR thus = 0 for R = CH3. Table 7-11 lists some values. Taft s Es steric constants are in some instances based on averages of several different reactions, so MacPhee et al. have defined a steric constant Es by Eq. (7-52) for a single reaction, namely, the acid-catalyzed esterification of carboxylic acids in methanol at 40°C. Es values are also given in Table 7-11. Additional Es and Es values are available. 

When a Br nsted base functions catalytically by sharing an electron pair with a proton, it is acting as a general base catalyst, but when it shares the electron with an atom other than the proton it is (by definition) acting as a nucleophile. This other atom (electrophilic site) is usually carbon, but in organic chemistry it might also be, for example, phosphorus or silicon, whereas in inorganic chemistry it could be the central metal ion in a coordination complex. Here we consider nucleophilic reactions at unsaturated carbon, primarily at carbonyl carbon. Nucleophilic reactions of carboxylic acid derivatives have been well studied. These acyl transfer reactions can be represented by... 

In addition to effects on biochemical reactions, the inhibitors may influence the permeability of the various cellular membranes and through physical and chemical effects may alter the structure of other subcellular structures such as proteins, nucleic acid, and spindle fibers. Unfortunately, few definite examples can be listed. The action of colchicine and podophyllin in interfering with cell division is well known. The effect of various lactones (coumarin, parasorbic acid, and protoanemonin) on mitotic activity was discussed above. Disturbances to cytoplasmic and vacuolar structure, and the morphology of mitochondria imposed by protoanemonin, were also mentioned. Interference with protein configuration and loss of biological activity was attributed to incorporation of azetidine-2-carboxylic acid into mung bean protein in place of proline. 

The study of optical isomers has shown a similar development. First it was shown that the reduction potentials of several meso and racemic isomers were different (Elving et al., 1965 Feokstistov, 1968 Zavada et al., 1963) and later, studies have been made of the ratio of dljmeso compound isolated from electrolyses which form products capable of showing optical activity. Thus the conformation of the products from the pinacolization of ketones, the reduction of double bonds, the reduction of onium ions and the oxidation of carboxylic acids have been reported by several workers (reviewed by Feokstistov, 1968). Unfortunately, in many of these studies the electrolysis conditions were not controlled and it is therefore too early to draw definite conclusions about the stereochemistry of electrode processes and the possibilities for asymmetric syntheses. 

Deuteration studies with acetic acid-d4 (99.5% atom D) as the carboxylic acid building block, ruthenium(IV) oxide plus methyl iodide-d3 as catalyst couple and 1/1 (C0/H2) syngas, were less definitive (see Table III). Typical samples of propionic and butyric acid products, isolated by distillation in vacuo and glc trapping, and analyzed by NMR, indicated considerable scrambling had occurred within the time frame of the acid homologation reaction. 

One of the most actively investigated aspects of the biohydrolysis of carboxylic acid esters is enantioselectivity (for a definition of the various stereochemical terms used here, see [7], particularly its Sect. 1.5) for two reasons, one practical (preparation of pure enantiomers for various applications) and one fundamental (investigations on the structure and function of hydrolases). The synthetic and preparative aspects of enantioselective biocatalysis by hydrolases have been extensively investigated for biotechnology applications but are of only secondary interest in our context (e.g., [16-18], see Sect. 7.3.5). In contrast, the fundamental aspects of enantioselectivity in particular and of structure-metabolism relationships in general are central to our approach and are illustrated here with a number of selected examples. 

An electrochemical explanation of the basic reaction was suggested by P rumkin 17), while Shilov et al. 22, 23) claimed surface oxides of definite structure to be the only cause of either acidic or basic reaction. Shilov formulated the acidic surface oxides as carboxylic acid anhydrides bound to the edges of the carbon layers. 

Each molecular transformation applied by Leatherface is specified by a SMARTS definition followed by a series of instructions that specify how the substructure matched by the SMARTS is to be modified. The first example shows how neutral carboxylic acids are converted to their more physiologically relevant anionic forms. The Pit instruction indicates that a single proton is to be removed (—1) from the atom matching the third atom in the SMARTS. 

Even though the ranges for individual types often overlap, it may be possible to make a definite decision from information derived from other regions of the IR spectrum. Thus esters also exhibit strong C-0 stretching absorption between 1200 and 1300 cm- while carboxylic acids exhibit 0-H stretching absorption generally near 3000 cm-. ... 

There are several examples of metabolites where the tetramic acid domain is teasingly disguised. In these cases, it is difficult to be definitive about the nature of the apparent modification unless this is substantiated by biosynthetic studies. The case of lactacystin (5), Fig. (2), has already been considered. Another example is presented by the oxazolomycin group of antibiotics, e.g. (Ill), found in strains of Streptomyces [179]. Biosynthetic studies indicate that the carboxylic acid of the amino acid required to form tetramic acids contributes to the formation of the 3-lactone [180]. In this section, metabolites that probably have a tetramic acid origin are presented. 

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