Glyoxilic acid

A similar reaction occurs when polyacrylamide is mixed with glyoxilic acid [298-12-4], C2H2O2, at pH about 8. This reaction produces a polymer with the CONHCH(OH)COOH fiinctionahty, which has found appHcation in phosphate ore processing (53). 

The formation of compound 2 is accompanied by the appearance of glyoxilic acid 8, which can be oxidized to oxalic acid 9 or directly to CO2. 

Fig. 2.133. HPLC chromatogram of pigment extracts from table olives cv. Gordal (a) healthy fruits and (b) altered fruits. Peaks 1 = 15-glyoxilic acid pheophorbide-b 2 = 15-glyoxilic acid pheophorbide-a 3 = Cu-15-glyoxilic acid pheophorbide-a 4 = pheophorbide-b 5 = pheophorbide-a 6 = pyropheophorbide-a 7 = 15-glyoxilic acid pheophytin-b 8 = Cu-15-glyoxilic acid pheophytin-b 9 = 15-glyoxilic acid pheophytin-a 10 = Cu-15-glyoxilic acid pheophytin-a 11 = 15 -OH-lactone-pheophytin-b 12 = 15 -OH-lactone-pheophytin-a 13 = 15-formylpheophytin-b 14 = pheophytin-b 14 = pheophytin-b 15 = 15-formylpheophytin-a 16 = pheophytin-a 16 = pheophytin-a 17 = pyropheophytin-b 18 = Cu-pheophytin-a 19 = Cu-15-formylpheophytin-a 20 = pyropheophytin-a 21 = Cu-pyropheophytin-a. Reprinted with permission from B. Ganul-Rojas el al. [304].

The conversion of glyoxals to glyoxilic acids is a special case of the... 

Glyoxilic acid (1) Dichloroacetic acid + H20 (2) Electrochemical reduction of oxalic acid with H2... 

Naphtho[l,2-rf]thiazole (244) cyclocondensates with glyoxilic acid derivatives to give naphtho-[l, 2 4,5]thiazolo[3,2-i>][l,2,4]triazin-9-ones (245) (Equation (39)) <93JHC1331>. 

Could be further oxidised to glyoxilic acid or oxalic acid. 

Hydroxylamine is known to be highly toxic to plants so the possibility that it is an obligatory intermediate in nitrate reduction must be considered with caution. Interest in hydroxylamine arises from the lengthy controversy, briefly mentioned here, concerning the rela-j five merits of hydroxylamine or ammonia as the key intermediate in nitrogen fixation. The toxicity of hydroxylamine may well be due to its action as an enzyme inhibitor. However, in spite of its toxicity, there are still some claims that hydroxylamine may be an intermediate in the formation of amino acids by oxime formation with such carbonyl compounds as glyoxilic acid (formed in photosynthesis), I pyruvate, a-ketoglutarate or oxaloacetate (intermediates in carbo-... 

More polymerized xanthylium structures with a X ax near 560 nm, resulting from the reaction between favanols and glyoxilic acid, have also been demonstrated to be formed in model solution, but their presence in wines has not yet been proved (Es-Safi etal, 2003). 

FIGURE 7.18 High-performance liquid chromatography (HPLC) separation of a mixture of standards of pheophytins and their oxidation products. Peaks 1,15-glyoxilic acid-pheophytin b 2, 15-gJyoxilic acid-pheophytin a 3, 15-OH-lactone-pheophytin b 4, 15-OH-lactone-pheophytin a 5, pheophytin b 5, pheophytin b C-13 epimer 6, pheophytin a, 6, pheophytin a C-13 epimer 7, phytol-purpurin 18 b ester 8, phytol-purpurin 18 a ester. 

Glyoxilic acid histofluorescence of the central nervous system Protocol 118... 

Brieskorn, C. H., and K. Danziger Color Reaction of Tryptophan and Glyoxilic Acid Sulfuric Acid. Z. Lebensm.-Unters. Forsch. 137, 362-370 (1968). 

---