Carboxylic acids pyruvic

Six carboxylic acids (pyruvic, tartaric, shikimic, lactic, acetic, succinic) were found in Nebbiolo wine and analyzed on a Cjg column (A = 230nm) using an aqueous 13 mM NaH2P04 with 2.6 mM (NH4)2S04 to pH 2.6 with H3PO4 mobile phase [1566]. Standard concentrations were 0.01-2mg/mL. Good peak shapes and... 

This is an example of the Doebner synthesis of quinoline-4-carboxylic acids (cinchoninic acids) the reaction consists in the condensation of an aromatic amine with pyruvic acid and an aldehj de. The mechanism is probably similar to that given for the Doebner-Miller sj nthesis of quinaldiiie (Section V,2), involving the intermediate formation of a dihydroquinoline derivative, which is subsequently dehydrogenated by the Schiff s base derived from the aromatic amine and aldehyde. 

In most biochemical reactions the pH of the medium is close to 7 At this pH car boxylic acids are nearly completely converted to their conjugate bases Thus it is common practice m biological chemistry to specify the derived carboxylate anion rather than the carboxylic acid itself For example we say that glycolysis leads to lactate by way of pyruvate... 

The first indolization of an arylhydrazone was reported in 1983 by Fischer and Jourdan" by treatment of pyruvic acid 1-methylphenylhydrazone 3 with alcoholic hydrogen chloride. However, it was not until the following year that Fischer and Hess identified the product from this reaction as 1-methyl indole-2-carboxylic acid 4. 

In 1883, Bottinger described the reaction of aniline and pyruvic acid to yield a methylquinolinecarboxylic acid. He found that the compound decarboxylated and resulted in a methylquinoline, but made no effort to determine the position of either the carboxylic acid or methyl group. Four years later, Doebner established the first product as 2-methylquinoline-4-carboxylic acid (8) and the second product as 2- methylquinoline (9). Under the reaction conditions (refluxing ethanol), pyruvic acid partially decarboxylates to provide the required acetaldehyde in situ. By adding other aldehydes at the beginning of the reaction, Doebner found he was able to synthesize a variety of 2-substituted quinolines. While the Doebner reaction is most commonly associated with the preparation of 2-aryl quinolines, in this primary communication Doebner reported the successful use of several alkyl aldehydes in the quinoline synthesis. 

Carboxylic acids with labile a-methylene protons react with isatin in the presence of strong aqueous base. In the total synthesis of methoxatin, the coenzyme of methanol dehydrogenase and glucose dehydrogenase, Weinreb employs a Pfitzinger condensation of an isatin 37 and pyruvic acid as a key step to provide the 4-quinolinic acid 38 in 50% yield under the standard basic conditions. ... 

Only in the case of the pyruvic acid condensation product was it possible to isolate the corresponding ethyl ester under these conditions. This, on mild hydrolysis, reverted to 1-methyl-1,2,3,4-tetrahydro-j8-carbohne-1-carboxylic acid, identical with the starting material, which therefore had the assigned structure 26 (R = CH3) and was not the SchiflF s base 25 (R = CH3). Alkaline hydrolysis of the ester was accompanied by decarboxylation. ... 

Compounds called carboxylic acids, which contain the -C02H grouping, occur abundantly in all living organisms and are involved in almost all metabolic pathways. Acetic acid, pyruvic acid, and citric acid are examples. 

Pd/Si02 was prepared at ICI Katalco and 4% Pd/Fe20j at Johnson Matthey Reactants used are shown in Table 1. Trifluorotiglic acid and its ester were synthesised by D Hunter at Glasgow University. The other unsaturated carboxylic acids (Aldrich), methyl pyruvate (Fluka), but-3-en-2-one (Aldrich), cinchonidine (Aldrich), cinchonine (Hopkin and Williams), ethanol (AnalaR grade, BDH) and THF (non stabilised, Fisons) were used as received... 

Other difunctional aliphatic carboxylic acids, e.g. lactic add, pyruvic acid, ethoxyacetic acid. 

Indole 2-carboxylic acids can be readily decarboxylated to afford an indole. Hence, using pyruvic acid as an aldehyde equivalent in the coupling with 24 gave... 

Composition and Structure. Chemical analysis of the polymer from our first strain (NCIB 11592) indicated that it was a polysaccharide containing the sugars, glucose and galactose, and the carboxylic acids - - succinic and pyruvic - - in the approximate ratios 7 1 1 1. 

These enzymes catalyse the non-hydrolytic cleavage of bonds in a substrate to remove specific functional groups. Examples include decarboxylases, which remove carboxylic acid groups as carbon dioxide, dehydrases, which remove water, and aldolases. The decarboxylation of pyruvic acid (10.60) to form acetaldehyde (10.61) takes place in the presence of pyruvic decarboxylase (Scheme 10.13), which requires the presence of thiamine pyrophosphate and magnesium ions for activity. 

Interestingly, the Fischer indole synthesis does not easily proceed from acetaldehyde to afford indole. Usually, indole-2-carboxylic acid is prepared from phenylhydrazine with a pyruvate ester followed by hydrolysis. Traditional methods for decarboxylation of indole-2-carboxylic acid to form indole are not environmentally benign. They include pyrolysis or heating with copper-bronze powder, copper(I) chloride, copper chromite, copper acetate or copper(II) oxide, in for example, heat-transfer oils, glycerol, quinoline or 2-benzylpyridine. Decomposition of the product during lengthy thermolysis or purification affects the yields. 

Xiao-Hua Yang et al. [ 1 ] determined nanomolar concentrations of individual low molecular weight carboxylic acids (and amines) in seawater. Diffusion of the acids across a hydrophobic membrane was used to concentrate and separate carboxylic acids from inorganic salts and most other organic compounds prior to the application of ion chromatography. Acetic propionic acid, butyric-1 acid, butyric-2 acid, valeric and pyruvic acid, acrylic acid and benzoic acid were all found in reasonable concentrations in seawater. 

Fig. 16. Ferredoxin (Fd)/ferredoxin-NADP+-reductase (FNR) mediated enzymatic carboxylation of pyruvic acid to form malic acid catalyzed by the NADPH-dependent malic enzyme (ME)...

The metabolism of cyanide has been studied in animals. The proposed metabolic pathways shown in Figure 2-3 are (1) the major pathway, conversion to thiocyanate by either rhodanese or 3-mercapto-pyruvate sulfur transferase (2) conversion to 2-aminothiazoline-4-carboxylic acid (Wood and Cooley 1956) (3) incorporation into a 1-carbon metabolic pool (Boxer and Richards 1952) or (4) combining with hydroxocobalamin to form cyanocobalamin (vitamin B12) (Ansell and Lewis 1970). Thiocyanate has been shown to account for 60-80% of an administered cyanide dose (Blakley and Coop 1949 Wood and Cooley 1956) while 2-aminothiazoline-4-carboxylic acid accounts for about 15% of the dose (Wood and Cooley 1956). The conversion of cyanide to thiocyanate was first demonstrated in 1894. Conversion of cyanide to thiocyanate is enhanced when cyanide poisoning is treated by intravenous administration of a sulfur donor (Smith 1996 Way 1984). The sulfur donor must have a sulfane sulfur, a sulfur bonded to another sulfur (e.g., sodium thiosulfate). During conversion by rhodanese, a sulfur atom is transferred from the donor to the enzyme, forming a persulfide intermediate. The persulfide sulfur is then transferred... 

In addition to the aforementioned allenic steroids, prostaglandins, amino acids and nucleoside analogs, a number of other functionalized allenes have been employed (albeit with limited success) in enzyme inhibition (Scheme 18.56) [154-159]. Thus, the 7-vinylidenecephalosporin 164 and related allenes did not show the expected activity as inhibitors of human leukocyte elastase, but a weak inhibition of porcine pancreas elastase [156], Similarly disappointing were the immunosuppressive activity of the allenic mycophenolic acid derivative 165 [157] and the inhibition of 12-lipoxygenase by the carboxylic acid 166 [158]. In contrast, the carboxyallenyl phosphate 167 turned out to be a potent inhibitor of phosphoenolpyruvate carboxylase and pyruvate kinase [159]. Hydrolysis of this allenic phosphate probably leads to 2-oxobut-3-enoate, which then undergoes an irreversible Michael addition with suitable nucleophilic side chains of the enzyme. 

Biochemical reactions include several types of decarboxylation reactions as shown in Eqs. (1)-(5), because the final product of aerobic metabolism is carbon dioxide. Amino acids result in amines, pyruvic acid and other a-keto acids form the corresponding aldehydes and carboxylic acids, depending on the cooperating coenzymes. Malonyl-CoA and its derivatives are decarboxylated to acyl-CoA. -Keto carboxylic acids, and their precursors (for example, the corresponding hydroxy acids) also liberate carbon dioxide under mild reaction conditions. 

Three-component coupling of an aniline, pyruvic acid, and an aldehyde to provide a quinoline-4-carboxylic acid. 

The direction of MCR involving pyruvic acid, aldehyde, and l-aryl substituted l,2,4-triazole-3,5-diamine was different from the directions of all other processes that were discussed earher. It was established [53] that this treatment yielded 3-(5-ammo-lH-l,2,4-triazol-3-ylamino)furan-2(5H)-one 39 instead of triazolopyri-midine carboxylic acids 38 (Scheme 16). 

Biotin (vitamin B ) is widespread in foods and is also synthesized by intestinal bacteria. It is a coenzyme for the carboxylation of pyruvate, acetyl-coenzyme-A (CoA), propionyl CoA, and /1-methyl-crotonyl CoA and is involved in fatty acid formation and in energy release from carbohydrates. In humans deficiencies only occur in patients with an abnormal gut flora and manifests itself as exfoliative dermatitis and alopecia. 

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