Pyruvate/pyruvic acid phenyl

Fischer indole synthesis. Emil Fischer discovered that pyruvic acid phenyl-liydiazone on being heated with zinc chloride loses ammonia with cyclization to... 

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. 

For the mechanism of this reaction, see Robinson and Robinson,1918, H3i 639 1924, 145, 827.) The reaction is of wide application for example, the use of methyl-phenyl-hydrazine, CsH5(CHj)> -iN H, in the above reaction gives i-methyl-2-phenylindole, whereas pyruvic acid, CH CO COOH, when converted to its phenylhydrazone and then indolised, gives indole-2-carboxylic... 

This is a slow process, and the extraction time depends on the type of extractor used. With stirring as described in Note 10, practically quantitative extraction of jb-hydroxy phenyl pyruvic acid can be achieved within 6 hours. Extremely long extraction times may cause decomposition of the product. 

Recently, Borner and coworkers described an efficient Rh-deguphos catalyst for the reductive amination of a-keto acids with benzyl amine. E.e.-values up to 98% were obtained for the reaction of phenyl pyruvic acid and PhCH2COCOOH (entry 4.9), albeit with often incomplete conversion and low TOFs. Similar results were also obtained for several other a-keto acids, and also with ligands such as norphos and chiraphos. An interesting variant for the preparation of a-amino acid derivatives is the one-pot preparation of aromatic a-(N-cyclohexyla-mino) amides from the corresponding aryl iodide, cyclohexylamine under a H2/ CO atmosphere catalyzed by Pd-duphos or Pd-Trost ligands [50]. Yields and ee-values were in the order of 30-50% and 90 >99%, respectively, and a catalyst loading of around 4% was necessary. 

Pyruvic acid Ephedra alkaloids Phenyl C Cathine Cathinone Ephedrine Norephedrine... 

A synthesis of acetylalanine, from which alanine can be obtained by hydrolysis, was described in 1900 by de Jong. Pyruvic acid was neutralised with ammonium carbonate there was a considerable rise in temperature, carbon dioxide was evolved and the ammonium salt of acetylalanine crystallised out The explanation of this reaction is based upon Erlenmeyer and Kunlin s synthesis of phenylalanine from phenyl-pyruvic acid and it proceeds as follows —... 

Subject Phenylacetic Acid Mandelic Acid o-Hydroxy- phenylacetic Acid Phenyllactic Acid Phenyl- pyruvic Acid p-Hydroxy- phenylacetic Acid... 

A mixture of 5-amino-A-phenyl-l//-pyrazole-4-carboxamide 1 (0.2 g, 1 mmol), pyruvic acid 4 (0.08 g, 1 mmol) and its aldehyde 5 (0.13 g, 1 mmol) was refluxed in 3 ml of acetic acid for 2 h (Scheme A.27). After cooling, the crystals precipitated were removed by filtration, washed with ethanol and air-dried. If required, the products were crystallized from ethanol. Yield 46%. 

Pyridinamine (54) with benzaldehyde and subsequently pyruvic acid gave 2-phenyl-l,8-naphthyridine-4-carboxylic acid (55) (EtOH, heat %).68... 

The a-cyano-a-naphthyl pyruvic acid ethyl ester shows a hydroxyl band at 3190 cm. 1 which is attributed to chelation (very strong intramolecular hydrogen bonding) (2). At 1717 cm. 1 it gives the a,/3-unsaturated carbonyl band of the enol form (lit. Ref. 2, 1715-1730 cm. 1). The phenyl ester shows the same bands at 3190 and 1717.5 cm. 1, respectively, whereas the thiophene ester spectrum shows intermolecular hydrogen bonding at 3310 cm.-1. Since the a-keto ester carbonyl band of the keto... 

Recent work on the thermal indolization of arylhydrazones has introduced new synthetic possibilities for azaindoles. Kelly et al. refluxed cyclohexanone and deoxybenzoin 2-pyridylhydrazones in diethylene glycol to give 5,6,7,8-tetrahydro-a-carboline (42, R = H) and 2,3-diphenyl-7-azaindole in 70 and 56% yields, respectively, compared with 53 and 12% reported earlier. Similarly, y-carboline 29 was obtained in 95 % yield from cyclohexanone 4-pyTidylhydrazone (lit. 48% ). Several 7-azaindole derivatives were prepared in the same manner. The yields ranged from 5 % for azaindolenine (31) to 88% for 3-phenyl-7-azaindole. 3,3-Dimethyl-7-azaindolenine was obtained in 47 % yield from the isobutyralaldehyde hydrazone. The novel cyclic compounds 40 and 41 were obtained from the 2-pyridylhydrazones of cyclopentanone, a-indanone, and a-tetralone in 67, 95, and 77% yields, respectively. Unfortunately, all attempts to cyclize the acetone, pyruvic acid, and ethyl pyruvate hydrazones were unsuccessful. Also, cyclohexanone and methyl ethyl ketone 5-nitro-2-... 

Several a-keto acids are easily obtained by hydrolysis of acyl cyanides. An improved procedure using cuprous cyanide in the preparation of the acyl cyanides is described. Hydrolysis of the acyl cyanides by cold concentrated hydrochloric acid is described for pyruvic acid (73%), a-ketobutyric acid, and benzoylformic acid (77%). Isovaleryl cyanide is not hydrolyzed under these conditions. Alkaline hydrolysis has been found to be more successful than acid hydrolysis in the preparation of the y-keto acid, a-phenyl-/S-benzoylpropionic acid (76%). ... 

The phenanthroindolizine alkaloids can be visualized as arising by the condensation of two molecules of dihydroxyphenylalanine or one molecule of dihydroxypheny]alanine and one of t3Tosine (or their equivalents, the corresponding benzoyl acetic and phenyl pyruvic acids) with ornithine (or its equivalent, y-aminobutyraldehyde). 

To date, four main types of catalytic activity have been reported in detail for thermal polyamino acids. These are (with the most studied substrates in parentheses) hydrolyses (p-nitrophenyl acetate, p-nitro-phenyl phosphate, ATP), decarboxylations (OAA, glucuronic acid, pyruvic acid), and aminations (a-ketoglutaric acid, OAA, pyruvic acid, phenylpyruvic acid). The fourth type is a deamination reaction yielding a-ketoglutaric acid (51). For some of the actions of the thermal polymers the products are identified quantitatively, and the kinds of amino acid side chain necessary for activity in the polymer elucidated. In others, products have yet to be fully identified. The activities of thermal polyamino acids are manifest on substrates which range from chemically labile to relatively stable. 

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