Oxalic acid derivatives

Langer and coworkers constructed diverse O- and N-heterocydic scaffolds, such as y-alkylidene-a-hydroxybutenolides and pyrrolo[3,2-b]pyrrol-2,5-diones, exploiting the well-established cyclization strategy of bisnucleophiles with oxalic acid derivatives [163], while Stockman s research group reported in this context on a novel oxime formation/Michael addition providing the structural core of the alkaloid perhydrohistrionicotoxin [164]. 

It was observed that glutamate and aspartate are diverted predominantly to the synthesis of cell substance rather than to the formation of oxalate. It is not inconsistent to see oc-ketoglutarate being formed from glutamate, while no oxaloacetic acid can be detected in the medium containing aspartate, as the oxaloacetic acid is known to be extremely unstable (2), (62), (Hi). The relatively low yields of oxalic acid, derived... 

The brilliant emissions resulting from the oxidation of certain oxalic acid derivatives, especially in the presence of a variety of fluorophores, are the bases of the most active area of current interest in CL. This group of chemiluminescent reactions has been classified as peroxyoxalate chemistry because it derives from the excited states formed by the decomposition of cyclic peroxides of oxalic acid derivatives called dioxetanes, dioxetanones, and dioxetanediones. 

The kinetics of the hydrolysis reactions of 4-amino-2-phenethyl- (354 R = PhCH2CH2) and 4-amino-2-cyclohexyl-2,3-dihydro-3-oxo-l,2,5-thiadiazole 1,1-dioxide (354 R = CeHii) have been investigated in the pH range 1-10 at 24-73 °C. The products are the corresponding new compounds 2-anuno-2-[(A -substituted-sulfamoyl)imino]acetic acid salts (355 R = PhCH2CH2 or CeHn) which hydrolyse further, in a slow reaction, to the sulfamide and oxalic acid derivatives. ... 

SCHEME 4. Chemiluminescence mechanism of an oxalic acid derivative in the presence of H2O2... 

In this reaction C02 can be produced at the anode by anodic oxidation of oxalic acid derivatives 369). In particular cases, the reaction can also be carried out in the presence of small amounts of water 370) ... 

Solventless condensation of a-dicarbonyl compounds (i.e., 1,2-diketones, a-oxo acids or esters, and oxalic acid derivatives) and benzene-1,2-diamine derivatives catalyzed by p-tolucnesulfonic acid under focussed microwave irradiation gives the corresponding 2,3-disubstituted quinoxa-line derivatives in almost quantitative yields. ... 

A number of chemiluminescent reactions are known. The oxidation of 3-aminophthalhydrazide (luminol) has been studied extensively. " The emission resulting from the reaction of certain oxalic acid derivatives is another outstanding example. When chemiluminescence occurs in living organisms, it is called bioluminescence. The best known example is observed in the firefly Photinus pyralis. Many review articles have... 

The axial chirality of the atropisomeric oxalic acid derivatives 57a, Z) according to Brewster also can be classified as helicity. (/ )-()-N,N,N, N -Tetramethyl-dithiooxamide 31a then constitutes one of the smallest molecular helices, the enantiomers of which have been separated semipreparatively using liquid chromatography... 

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