Of pyruvic acid

Occurs in coal tar, in various plants and in faeces, being formed by the action of the intestinal bacteria on tryptophan. It can be prepared by the action of acid on the phenyl-hydrazone of pyruvic acid to give indole-2-carboxylate which can be decarboxylated to indole. 

Biological reduction of pyruvic acid catalyzed by the enzyme... 

The enzyme is a single enantiomer of a chiral molecule and binds the coenzyme and substrate m such a way that hydride is transferred exclusively to the face of the carbonyl group that leads to (5) (+) lactic acid Reduction of pyruvic acid m the absence of an enzyme however say with sodium borohydride also gives lactic acid but as a racemic mixture containing equal quantities of the R and S enantiomers... 

A. Chloropyruvic acid. In a 1-1. four-necked flask (Note 1) fitted with a sealed mechanical stirrer, dropping funnel, thermometer, and reflux condenser protected with a calcium chloride tube is placed 249 g. (2.83 moles) of pyruvic acid (Note 2). The stirrer is started and 394 g. (2.92 moles) of sulfuryl chloride (Note 3) is added dropwise over a period of 2 hours. During the addition the temperature is maintained at 25-30° by cooling with a water bath. 

The method of synthesis described for chloropyruvic acid is essentially that reported. This procedure affords the product in excellent yields from readily available materials by a short, convenient route. Other less acceptable methods involve chlorination of pyruvic acid with sulfur dichloride or hypochlorous acid and the treatment of ethyl chloro(l-hydroxyheptyl)- or (o -hydroxybenzyl)oxalacetate 7-lactone with 50% hydrochloric acid. ... 

Methylindole has been prepared from the a5-methylphenyl-hydrazone of pyruvic acid, by the action of sodium amide or sodium hydride on indole followed by methyl iodide at elevated temperatures,by treatment of indole with methyl p-toluene-sulfonatc and anhydrous sodium carbonate in boiling xylene, and by the action of inelhyl sulfate on indole previously treated... 

Reaction.—Dissolve a diop of phenylhydrazine in two diojis of glacial acetic acid, dilute with about i c.c. of water, and acid a diop of pyruvic acid. A yellow crystalline piecipitate of tlio phen)Ihydrazone, CH3.C (N.NH.C(,H5).CO.OH, is formed. 

In this scheme the reversible conversion of A to O is the reaction whose rate is to be studied, whereas the reduction of O to R is the electrode process. Scheme XIV can also represent a pseudo-first-order formation of O. A specific example is the acid-base equilibrium of pyruvic acid, shown in Scheme XV. 

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. 

A solution of o-toluidine (28g, 260 mmol) in ethanol (50 mL) was added to a solution of pyruvic acid (33g, 380 mmol) and benzaldehyde (28g, 260 mmol) in ethanol (100 mL). The mixture was heated to reflux for 3 h and allowed to cool overnight. The resulting solid was collected by filtration, washed with ethanol, washed with benzene, and dried to give 32 (13.4g, 20% yield). 

With semicarbazones of lower a-keto acids the reaction proceeds with some difficulty or not at all. Thus, the semicarbazones of pyruvic acid cannot be cyclized and that of glyoxylic acid is predominantly hydrolyzed so that the yield of the cyclization product is only 20-25%. ° This reaction was used in work with a different object, for preparing 6-azauracil, for the first time. 

A uniformly favorable effect is displayed by an alkyl group, in position 2. Thus the 2-methylthiosemicarbazone of pyruvic acid is cyclized at normal temperature and without excess hydroxide. The 2-methylthiosemicarbazone of glyoxylic acid (98) was cyclized by boiling for 5 min to 2-methyl-3-thioxo-5-oxo-2,3,4,5-tetrahydro-... 

The cyclization of the 4-methylthiosemicarbazone of pyruvic acid was recently effected by refluxing in dimethylformamide, ... 

Catalytic reduction of the nitrile 79 in the presence of semicarbazide affords initially the semicarbazone of 80. Hydrolysis-interchange, for example in the presence of pyruvic acid, gives the aldehyde 80. Condensation with the half ester of malonic acid leads to the acrylic ester 81 the double bond is then removed by means of catalytic reduction (82). Base catalyzed reaction of the... 

Very characteristic of citral is the compound which it forms with S-naphthocinchoninic acid. It is obtained in the following manner Twenty grams of citral and 20 grams of pyruvic acid are dissolved in absolute alcohol, and 20 grams of j8-naphthylamine are added. The whole is heated for three hours on the water-bath under a reflux condenser. 

Yet a third method for the synthesis of a-amino acids is by reductive amination of an a-keto acid with ammonia and a reducing agent. Alanine, for instance, is prepared by treatment of pyruvic acid with ammonia in the presence of NaBH As described in Section 24.6, the reaction proceeds through formation of an intermediate imine that is then reduced. 

Write a balanced equation for the oxidation of pyruvic acid to CC and H20. 

Let us look at a very simple part of the overall process. The first thing that happens is the breakdown of pyruvic acid into acetic acid and CO (the oxidation process has started ) ... 

Figure 8.7 gives a typical time course for the conversion of pyruvic acid to L-phenylalanine. 

Reactions involve several enzymes, which have to follow in sequence for lactic acid and alcohol fermentation. This is known as the glucose catabolism pathway, with emphasis on energetic and energy carrier molecules such as ATP, ADP, NAD+ and NADH. In this pathway the six-carbon substrate yields two three-carbon intermediates, each of which passes through a sequence of reactions to the stable end product of pyruvic acid. 

For instance, trenbolone fluoresces yellow [12] and the qinoxalone derivative of pyruvic acid yellow-green [18]. In the case of steroids and Digitalis glycosides it is possible to differentiate on the basis of various fluorescence colors [8, 9, 15]. 

A small fan should be used during the application of pyruvic acid to avoid inhaling the vapors... 

Cotellessa C, Manunta T, Ghersetich I, Brazzini B, Lotti T, Peris K (2005) The use of pyruvic acid in the treatment of acne. J Eur Acad Dermatol Venereol (in press)... 

Griffin TD,Van Scott EJ,Maddin S (1989) The use of pyruvic acid as a chemical peeling agent. J Dermatol Surg Oncol 15 1316... 

Griffin TD, Van Scott EJ (1991) Use of pyruvic acid in the treatment of actinic keratoses a clinical and histopathologic study. Cutis 47 325-329 Halasz CL (1998) Treatment of warts with topical pyruvic acid with and without added 5-fluoruracil. Cutis 62(6) 283-285... 

Some sugar residues in bacterial polysaccharides are etherified with lactic acid. The biosynthesis of these involves C)-alkylation, by reaction with enol-pyruvate phosphate, to an enol ether (34) of pyruvic acid, followed by reduction to the (R) or (5) form of the lactic acid ether (35). The enol ether may also react in a different manner, giving a cyclic acetal (36) of pyruvic acid. 

Cyclic acetals of pyruvic acid are common in extracellular polysaccharides (compare, for example, Ref. 6). They have also been found in some LPS, namely, those from Shigella dysenteriae type 6 and E. coli 0-149 (Ref. 139), and in the teichoic acid from Brevibacterium iodinum. The biosynthesis of these acetals has already been discussed. 

Aerobic living features metabolize sugars and fatty acids to carbon dioxide. Accordingly, there are some kinds of decarboxylation reactions. TPP-mediated decarboxylation of pyruvic acid to acetaldehyde is one of the most important steps of the metabolism of sugar compounds (Fig. 1). When the intermediate reacts with lipoic acid instead of a proton, pyruvic acid is converted to acetylcoenzyme A, which is introduced to TCA cycle (Fig. 2). 

---