Fumaric acid organic compounds

Organic compounds such as lactic acid [74, 75], citric acid [74], fumaric acid [76, 77], and amino acids [74] were also shown to catalyze the ROP of lactones, using alcohols and amines as initiators. Interestingly, an acid catalyst can be supported on a solid support such as porous silica [78]. Unfortunately, the polymerization is slow and reuse of the catalyst after its recovery and regeneration turned out to be unsuccessful. Finally, it is worth noting the particular behavior of amino acids, which are able to both catalyze and initiate the ROP of lactones [79]. 

One of the first persons to study the oxidation of organic compounds by animal tissues was T. Thunberg, who between 1911 and 1920 discovered about 40 organic compounds that could be oxidized by animal tissues. Salts of succinate, fumarate, malate, and citrate were oxidized the fastest. Well aware of Knoop s (3 oxidation theory, Thunberg proposed a cyclic mechanism for oxidation of acetate. Two molecules of this two-carbon compound were supposed to condense (with reduction) to succinate, which was then oxidized as in the citric acid cycle to oxaloacetate. The latter was decarboxylated to pyruvate, which was oxidatively decarboxylated to acetate to complete the cycle. One of the reactions essential for this cycle could not be verified experimentally. It is left to the reader to recognize which one. 

Photolysis [KINETTCMEASUREMENTS] (Vol 14) maleic anhydnde [MALEIC ANHYDRIDE, MALEIC ACID AND FUMARIC ACID] (Vol 15) of molybdenum compounds [MOLYBDENUM AND COMPOUNDS] (Vol 16) of pesticides [SOIL CHEMISTRY OF PESTICIDES] (Vol 22) of silanes [SILICON COMPOUNDS - SILANES] (Vol 22) of titanium compounds [TITANIUM COMPOUNDS - ORGANIC] (V ol 24)... 

Ion exclusion chromatography has been applied to the determination of the following organic compounds and anions ozonisation products, carboxylic acids phosphate, nitrite, nitrate, silicate, bicarbonate, tartrate, malate, malonate, citrate, glycollate, formate and fumarate, arsenite, arsenate, chloride, bromide, iodide, thiocyanate and sulphate carbonate and also the cation arsenic. 

High-oxygen, nitrogen-free organic compounds (C, H, 0) are blended with inorganic oxidisers. The fuels used are, for example, tri or dicarboxylic acids (e.g. citric acid, tartaric acid, fumaric acid) or similar compounds. The oxidisers used are especially perchlorates and chlorates with additional assistance from metal oxides. This enables any formation of NOx to be excluded. 

Until now, examples were discussed in which amino acids are produced from mixed organic matter substrates. It is also possible to start with defined chemical compounds. An example is the synthesis of L-alanine from fumaric acid in a two-step reaction. Other examples for a highly selective fermentation are the synthesis of L-Dopa from orthocatechol and of L-tyrosine from phenol. 

It is also possible to convert nonchiral readily available industrial organic chemicals into valuable chiral natural-analogue products. This is demonstrated by the conversion of achiral fumaric acid to L(-)-malic acid with fumarase as the active enzyme. The same compound is converted to the amino acid L(-h)-aspartic acid by Escherichia bacteria that contain the enzyme aspartase. If pseudomonas bacteria are added, another amino acid L-alanine is formed (Eq. 9.10). 

By using both C18 and Aminex HPLC column, succinic, citramalic and fumaric acid can also be determined in the same run of the other organic acids. With C18 columns, these compounds exit in the chromatogram after citric acid in the sequence succinic-citramalic-fumaric in the chromatogram using the Aminex column, succinic acid exits close to shikimic acid, the fumaric acid peak falls between those of lactic acid and acetic acid. 

Wine is a polar liquid suitable for direct application to SPE sorbents without sample preparation. Because the polarity of organic acids and anthocyanins differs widely, two SPE sorbents are used. Tartaric, malic, and fumaric acids are polar (Fig. 9.6) and not isolated by C-18. Rather, ion exchange is the method of isolation for these compounds. Anthocyanins, on the other hand, are nonpolar and may be retained by a reversed-phase mechanism. Thus, two types of sorbents are required for this method. 

Molecules containing carboxylic acid functionalities are not confined to organic systems. For example, the C=C double bond in fumaric acid can interact with a low oxidation state metal centre (see Chapter 23) to form organometallic compounds such as Fe(C0)4(r -H02CCHCHC02H) the T -prefix (see Box 18.1) indicates that the two carbon atoms of the C=C bond of the fumaric acid residue are linked to the Fe centre. Hydrogen bonding can occur between adjacent pairs of molecules as is depicted below, and such interactions extend through the solid state lattice to produce an extensive, three-dimensional array. 

Numerous organic acids have been identified in tobacco. These volatile, nonvolatile, and amino acids have been discussed in-depth by Tso [see Chapter 24 in (3973)]. The major nonvolatile acids are 2-hydroxy-l,2,3-propanetricarboxylic (citric), hydroxybutanedioic (malic), and ethanedioic (oxalic). The minor nonvolatile acids are hydroxyacetic (glycolic), butanedioic (succinic), propanedioic acid (malonic), butene-dioic (E) (fumaric acid), and 2-oxopropanoic (pyruvic). The major volatile acids in tobacco are acetic and formic acid minor volatile acids are propanoic, 2-furancarboxylic acid (2-furoic), benzoic, a-methylbutyric, P-methylvaleric, and numerous others. Over forty amino acids and related compounds have been identified in tobacco [Leffingwell (2337)]. 

More reeently, we have reported a novel example of double reactivity in other ionic organic supramolecular assembly [(HFu )(Im )], where HFu hydrogen fumarate and Im" imidazolium). This assembly can be obtained as a single ciystalline phase by solvent-free mechanical grinding of fumaric acid (H2FU) and imidazole (Im) compounds for at least 1 min. This compound represents an unprecedented example of double reactivity by either photochemical [2 + 2] or thermal reaction. 

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