Substrate studies oxide elimination

This mechanism is supported by the fact that every 3-oxoalkylarsonic acid studied also eliminated arsenite. First, 3-hyroxypropylarsonic acid proved to be a substrate for alcohol dehydrogenase from yeast, and similarly eliminated arsenite. Further, the oxidation by periodate of the HO—CH2—CHOH—CH2—CH2—As03H2, expected to produce 0=CH—CH2—CH2—As03H2 (another 3-oxoalkylarsonic acid), also yielded arsenite, and conditions that normally transaminate amino acids, when applied to the glutamate analogue HOOC—CH(—NH2)—... 

The mechanism of flavin reduction in b2 has been a topic of debate for decades. Soon after it was discovered that DAAO could catalyze the elimination of Cl from chlorinated substrates, very similar experiments were conducted with many a-hydroxy acid oxidizing enzymes, including F 2- However, HCl elimination was not observed when using 3-Cl-lactate as a substrate. Studies using 3-Br-pynivate as an electron acceptor for lactate oxidation were interpreted as evidence of a carbanion mechanism of flavin reduction. ... 

The biosynthesis of the nucleoside skeleton of polyoxins has been studied using C- and C-labelled glucose, glycerate, and uridine substrates it was suggested that condensation of uridine as its 5 -aldehyde with phosphoenol pyruvate gives an octofuranuloseuronic acid nucleoside, which loses the two terminal carbon atoms by oxidative elimination followed by transamination to give the required uridyl-5-amino-5-deoxy-D-allofuranosyluronic acid structure. ... 

Ca.ta.lysis, Iridium compounds do not have industrial appHcations as catalysts. However, these compounds have been studied to model fundamental catalytic steps (174), such as substrate binding of unsaturated molecules and dioxygen oxidative addition of hydrogen, alkyl haHdes, and the carbon—hydrogen bond reductive elimination and important metal-centered transformations such as carbonylation, -elimination, CO reduction, and... 

The proposed mechanism is given in Scheme 15. Initially the dissociation of water, maybe trapped by the molecular sieve, initiates the catalytic cycle. The substrate binds to the palladium followed by intramolecular deprotonation of the alcohol. The alkoxide then reacts by /i-hydride elimination and sets the carbonyl product free. Reductive elimination of HOAc from the hydride species followed by reoxidation of the intermediate with dioxygen reforms the catalytically active species. The structure of 13 could be confirmed by a solid-state structure [90]. A similar system was used in the cyclization reaction of suitable phenols to dihydrobenzofuranes [92]. The mechanism of the aerobic alcohol oxidation with palladium catalyst systems was also studied theoretically [93-96]. 

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