Pyruvic aldehyde

Isonitrosoacetone (unfi-pyruvic aldehyde-l-oxime) [31915-82-9] M 87.1, m 69". Crystd from ether/pet ether or CCI4. 

Iminium ions bearing an electron-withdrawing group bonded to the sp carbon of the iminium function are very reactive dienophiles. Thus, iminium ions 26 generated from phenylglyoxal (Scheme 6.15, R = Ph) or pyruvic aldehyde (R = Me) with methylamine hydrochloride, react with cyclopenta-diene in water at room temperature with good diastereoselectivity [25] (Scheme 6.15). If glyoxylic acid is used, the formation of iminium salt requires the free amine rather than the amine hydrochloride. 

A micro-diffusion method has been devised by Winnick101 for the determination of acetaldehyde. Procedures for the assay of glycerose were developed by Jayme, Satre and Maris.167,168 They dehydrated glycerose to pyruvic aldehyde by distillation from mineral acid, and determined the pyruvic aldehyde as its phenylosazone. 

Methylquinoxaline may be prepared in 88-92% yields from o-phenylenediamine and pyruvic aldehyde-sodium bisulfite by this same procedure. 

Propionitrile, 51 -Propylacetylene, 17 2,3-Pyrazinedicarboxylic acid, 86 Pyridine, 3-amino, 3 Pyridine, 5-ethyl-2-methyl, 41 Pyruvic aldehyde-sodium bisulfite, 88... 

Quinoxaline has been prepared by the reaction of glyoxal with o-phenylenediamine, and 2-methylquinoxaline by the reaction of pyruvic aldehyde or isonitrosoacetone with < -phenylenedi-amine. 2,3-Pyrazinedicarboxylic acid has been prepared only by the permanganate oxidation of quinoxaline. 2-Methyl-5,6-pyrazinedicarboxylic acid has been prepared from 2-methyl-quinoxaline in the same way. - ... 

Oxidation of a glycol can lead to a variety of products. Periodic acid quantitatively cleaves 1,2-glycols to aldehydes and is used as an analysis method for glycols (12,13). The oxidation of propylene glycol over Pd/C modified with Pb, Bi, or Te forms a mixture of lactic acid, hydroxyacetone, and pyruvic acid (14). Air oxidation of propylene glycol using an electrolytic crystalline silver catalyst yields pyruvic aldehyde. 

A model system demonstrating the nutritional destruction of lysine in bovine plasma albumin (BPA) by reaction with either a dialdehyde (MA) or a keto-aldehyde (MGA) was studied in relation to reaction rates as affected by pH, temperature, reaction time and carbonyl concentration. The BPA was Fraction V obtained from Schwartz/Mann and had a molecular weight of 69 x 103 with sixty lysine residules/mole, an assayed content of 11.4%. It was dissolved in 0.0200 M phosphate-citrate buffer adjusted to the desired pH. Malonaldehyde was prepared by acid hydrolysis of its bis-(dimethyl acetal). An aqueous solution of pyruvic aldehyde was diluted with distilled water and phosphate-citrate buffer to give an MGA solution of the desired pH (16). 

Pyruvic acid, 31, 59, 61 Pyruvic acid, ethyl ester, 31, 59 Pyruvic aldehyde-sodium bisulfite, 30, 88... 

Also acetic acid may arise from a reaction of this type. Most important compounds of this pathway are pyruvic aldehyde, diacetyl, hydro-oxyacetone and hydroxydiacetyl which can easily react with amino acids. The Strecker degradation is a reaction where the amino acid is de-carboxylated and loses its amino group. Reaction products are the Strecker aldehyde and - as an intermediate - an aminoketone which forms a pyrazine by dimerization. This pathway is considered to be most important for the origin of pyrazines in thermal aromas. However, only limited knowledge is available about the fate of the Strecker aldehydes. As we will demonstrate they are very reactive. 

Scheme 14. Organocatalyzed aldol reactions of the pyruvic aldehyde dimethyl acetal 59 with aldehydes 6...

The reaction of a-phosphoryl sulfoxide with the dimethyl acetal of pyruvic aldehyde allowed the preparation of the corresponding vinylic sulfoxide as a 1 1 mixture of (E) and (2) isomers which could be isomerized with Lithium Diisopropylamide to the lithiated (E) isomer, used for the asymmetric synthesis of a-tocopherol (eq 9). ... 

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