Succinate isolation

COs to form oxalacetate which under anaerobic conditions is reduced to malate. The malate in turn may be converted to fumarate and succinate (Fig, 5). The last step in this series of reactions is blocked by malonate. The second pathway involves the aerobic condensation of pyruvate and oxalacetate followed by oxidation of the condensation product to form -ketoglutarate and succinate. Wood has proposed that the first condensation product of the aerobic tricarboxylic cycle is cfs-aconitic acid which is then converted to succinate by way of isocitric, oxalosuccinic, and a-ketoglutaric acids. The a-ketoglutarate is decarboxylated and oxidized to succinic acid. Isotopic a-ketoglutarate containing isotopic carbon only in the carboxyl group located a to the carbonyl would be expected to yield non-isotopic succinate after decarboxylation. This accounts for the absence of isotopic carbon in succinate isolated from malonate-poisoned liver after incubation with pyruvate and isotopic bicarbonate. 

The isolation of an aliphatic acid from its aqueous solution, particularly in the presence of metallic salts, is a tedious operation (cf. p. 56), although a few such acids, e.g., succinic acid, can be extracted with ether. Since, however, a solution of an acid or one of Its salts is admirably suited for most of the tests in this series, the isolation of the free acid is rarely necessary except as a nieans of distinguishing (as in (i)) between aliphatic and aromatic members. 

It can be found in animal tissues (1), in vegetables and fmit (2,3), or in spring water (4), and has also been identified in meteorites (5). It is formed in alcohohc fermentation (6) and in the chemical and biochemical oxidation of fats. Succinic acid is present in amber (7) Succinuni) and can be obtained by distillation, by which method it was first isolated by Georgius Agricola in 1550. 

One of the methods used to isolate succinic acid from the waste stream of the adipic acid process is esterification of the mixture of succinic, glutaric, and adipic acid followed by fractionation (65—69). 

The correct structure (3) for this compound was first proposed in 1922 by Pieroni and Moggi on the basis of the isolation of succinic acid by chromic acid oxidation. Full confirmation of this structure was more recently obtained by Potts and Smithby the degradation outlined in Scheme 1. The dipyrrylbutane was synthesized by the lithium aluminum hydride reduction of the known dipyrrylbutane-... 

You probably came up with the suggestion that by using an esterase which selectively hydrolyses the succinate ester of L-menthol, you would be able to isolate L-menthol from the mixture. This is in essence the way the process is carried out commercially. We can represent this process by ... 

Advances in analytical procedures resulted in several reports on anthocyanins acy-lated with hydroxycinnamic acids (p-coumaric, caffeic, ferulic, sinapic, and 3,5-dihydroxycinnamic acids), hydroxybenzoic acids (p-hydroxybenzoic and gallic acids), and aliphatic acids (malonic, acetic, malic, oxalic, succinic and tartaric acids). However, not all of them were found in anthocyanins isolated from foods. Among the 44 fruits listed in Table 4.3.1, 15 presented acylated anthocyanins as did 12 of 13 vegetables shown in Table 4.3.3 and 2 of the 9 grains cited in Table 4.3.4. On the other hand, acylated anthocyanins were found in all grapes from Vitis species, although at different abundance levels, as can be seen in Table 4.3.2. A higher... 

Einster K, E Bak (1993) Complete oxidation of propionate, valerate, succinate, and other organic compounds by newly isolated types of marine, anaerobic, mesophilic. Gram-negative sulfur-reducing eubacteria. Appl Environ Microbiol 59 1452-1460. 

The formation of a DPP molecule was first reported in 1974 as a minor product in low yield from the reaction of benzonitrile with ethyl bro-moacetate and zinc. A fascinating study by research chemists at Ciba Geigy into the mechanistic pathways involved in the formation of the molecules led to the development of an efficient one-pot synthetic procedure to yield DPP pigments from readily available starting materials, as illustrated in Scheme 4.10. The reaction involves the treatment of diethyl succinate (1 mol) with an aromatic cyanide (2 mol) in the presence of a strong base. The reaction proceeds through the intermediate 88, which may be isolated and used to synthesise unsymmetrical derivatives. 

Abnormalities of the respiratoiy chain. These are increasingly identified as the hallmark of mitochondrial diseases or mitochondrial encephalomyopathies [13]. They can be identified on the basis of polarographic studies showing differential impairment in the ability of isolated intact mitochondria to use different substrates. For example, defective respiration with NAD-dependent substrates, such as pyruvate and malate, but normal respiration with FAD-dependent substrates, such as succinate, suggests an isolated defect of complex I (Fig. 42-3). However, defective respiration with both types of substrates in the presence of normal cytochrome c oxidase activity, also termed complex IV, localizes the lesions to complex III (Fig. 42-3). Because frozen muscle is much more commonly available than fresh tissue, electron transport is usually measured through discrete portions of the respiratory chain. Thus, isolated defects of NADH-cytochrome c reductase, or NADH-coenzyme Q (CoQ) reductase suggest a problem within complex I, while a simultaneous defect of NADH and succinate-cytochrome c reductase activities points to a biochemical error in complex III (Fig. 42-3). Isolated defects of complex III can be confirmed by measuring reduced CoQ-cytochrome c reductase activity. 

Mitsubishi have reported several processes based on Ru-catalyzed hydrogenation of anhydrides and acids. Succinic anhydride can be converted into mixtures of 1,4-butane-diol and y-butyrolactone using [Ru(acac)3]/trioctylphosphine and an activator (often a phosphonic acid) [97]. Relatively high temperatures are required ( 200°C) for this reaction. The lactone can be prepared selectively under the appropriate reaction conditions, and a process has been developed for isolating the products and recycling the ruthenium catalyst [98-100]. 

By screening a variety of lipases in organic solvent for their ability to acylate the racemic hydroxynitrile with succinic anhydride, Novozym 435 was found to yield the best results, affording product in 94-95 % ee at conversions of 47 9 % (Scheme 1.34). After optimization, the reaction was successfully run at 22 kg scale. The immobilized catalyst could be easily isolated by filtration and reused. 

Biological. Heukelekian and Rand (1955) reported a 5-d BOD value of 1.31 g/g which is 58.7% of the ThOD value of 2.23 g/g. A Nocardia sp. isolated from soil was capable of transforming pyridine, in the presence of semicarbazide, into an intermediate product identified as succinic acid semialdehyde (Shukla and Kaul, 1986). 1,4-Dihydropyridine, glutaric dialdehyde, glutaric acid semialdehyde, and glutaric acid were identified as intermediate products when pyridine was degraded by Nocardiastiain Z1 (Watson and Cain, 1975). 

In studies with Isolated plant mitochondria, flavones, flava-nones, cinnamic acids, and benzoic acids were shown to Inhibit the oxidation of succinate, malate, and NADH Inhibition was... 

Distearoyl-.vn-glycerol (lg, 1.6 mmol), succinic anhydride (0.2 g, 2 mmol), and DMAP (0.24 g, 2 mmol) were dissolved in CH2C12 (10 mL). The mixture was stirred at rt for 1 h, the solvent was removed and the product was isolated (silica gel, EtOAc/hexane 9 1). 

---