Diphenyl pyruvic acid

A solution of Grignard reactive (prepared from 247 g of o-bromoanisole and 31.6 g of magnesium in 1500 ml of ether) is added dropwise to a solution of 91 g of diphenyl pyruvic acid in ether. The mixture is refluxed for 2 hours. After cooling to the reaction mixture is added 5% hydrochloric acid and the product is extracted with 5% solution of sodium hydroxide. a-(o-Anisyl)-p,15-diphenyl lactic acid is precipitated by addition of concentrated hydrochloric acid yield 62 g, melting point 194-195°C. 

The photoreactions of phenylglyoxylic acid (28) are similar to those of pyruvic acid. In isopropyl alcohol it is photoreduced to diphenyl tartaric... 

There has been some interest in Doebner s pyruvic acid synthesis of l-carboxy-4,7-phenanthrolines. The claim that i,10-dicarboxy-3,8-diphenyl-4,7-phenanthroline is got by one-step synthesis from p-phenylenediamine240 is disputed,241 although the synthesis of 1-carboxy-3,8-diphenyl-4,7-phenanthroline is accomplished from 6-amino-2-phenylquinoline. 

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-... 

Finally, in strongly alkaline solution formazans containing removable substituents such as COOH, COCH3, and COCOOH in position 3 can couple with a third diazonium component, giving the so-called 3-(phenylazo)form-azans for instance, l,5-diphenyl-3-(phenylazo)formazan, C6H5NH—N=C-(N=NC6H5)2, is obtained as end-product of complete coupling of acetone,344 acetaldehyde,344 351 354 pyruvic acid,344 351 acetoacetic acid,344 352 malonic acid,343 or acetonedicarboxylic acid,343 etc. 

As in 4,5-disubstituted phenanthrenes, substitutions at the sterically most hindered Cl and CIO positions of 4,7-phenanthroline as depicted in 49 (Fig. 15) cause helical twist of the aromatic structure [54]. The first example of such derivatives, 1,10-dicarboxy-3,8-diphenyl-4,7-phenanthroline (50), was reported in 1932 (Scheme 9) [55]. Condensation of p-phenylenediamine with benzaldehyde and then with pyruvic acid followed by cyclization produced 50. Oxidation of 50 to tetracarbox-ydipyridyl 51 provided the supporting evidence for the formation of 50. 

Theoretically, the condensation of mono- and diiodotyrosine could yield four different compounds 3,3 -diiodothyronine, 3,3, 5 -triiodothyronine, 3,5,3 -triio-dothyronine, and thyroxine (see Fig. 8-4). The exact mechanism of the formation of these various iodinated derivatives is not clear, but it has been suggested that they are formed by the condensation of two molecules of iodotyrosines with loss of a side chain. In this reaction, the iodinated tyrosine is converted by the loss of two atoms of hydrogen to the quinoid form, which acts as a free radical and condenses with other molecules of iodinated tyrosine to yield a diphenyl ring. During such a reaction, an oxygen bridge is formed, and one of the side chains of tyrosine is split to yield an a-amino acrylic acid. The a-amino acrylic acid is further metabolized to yield ammonia and pyruvic acid. 

Acetalization. Cyclic acetals of pyruvic acid are not easily prepared by using commonly available acetalization methods. Cyclic pyruvic acid acetals of carbohydrates were prepared by DMTST-promoted transacetalization reaction between methyl pyruvate diphenyl dithioacetal and carbohydrate... 

By acylation of amines with active derivatives of a-keto acids pyruvic acid chloride (767), p-nitrophenyl pyruvate 167, 169), carbodimide method 86. 166, 178), mixed anhydrides with phosphorous acid dichloride 436) and by activation with the cyclic esters of oxalic acid with 4,6-diphenyl-thieno-[3,4-d]-[l,3]-dioxolone-dioxide (H. Schmidt and W. Steglich, 346A). 

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