Combination step nitrogen oxide production

Diacetyl, and its reduction products, acetoin and 2,3-butanediol, are also derived from acetaldehyde (Fig 8D.7), providing additional NADH oxidation steps. Diacetyl, which is formed by the decarboxylation of a-acetolactate, is regulated by valine and threonine availability (Dufour 1989). When assimilable nitrogen is low, valine synthesis is activated. This leads to the formation of a-acetolactate, which can be then transformed into diacetyl via spontaneous oxidative decarboxylation. Because valine uptake is suppressed by threonine, sufficient nitrogen availability represses the formation of diacetyl. Moreover, the final concentration of diacetyl is determined by its possible stepwise reduction to acetoin and 2,3-butanediol, both steps being dependent on NADH availability. Branched-chain aldehydes are formed via the Ehrlich pathway (Fig 8D.7) from precursors formed by combination of acetaldehyde with pyruvic acid and a-ketobutyrate (Fig 8D.7). 

The attractive combination of transition metals and iodobenzene diacetate as strong oxidant allowed the subsequent development of additional diamination reactions. For example, in the presence of a conventional ttiphenylphosphino-gold(l)chloride complex, intramolecular diamination using ureas as nitrogen sources proceeds within a gold(l/lll) cycle with results that are comparable to the mentioned paUadium(II/IV) catalysis [99]. However, as the initial step consists of an anti-aminoauration, this reaction provides the opposite stereochemistry with respect to the overall product configuration. 

A single reagent (53) is offered in place of the combination of ninhydrin and phenylacetaldehyde for the fluorimetric assay of primary amines. Deamination of primary amines leads to the same product distribution whether nitrogen or nitrous oxide is the gas molecule expelled once again, the existence of disorder in the product-forming steps is invoked. Micellar stereochemical control in nitrous acid deamination has been reported. ... 

The following cycle of copper experiment is performed in some general chemistry laboratories. The series of reactions starts with copper and ends with metallic copper. The steps are as follows (1) A piece of copper wire of known mass is allowed to react with concentrated nitric acid [the products are copper(II) nitrate, nitrogen dioxide, and water]. (2) The copper(II) nitrate is treated with a sodium hydroxide solution to form copper(II) hydroxide precipitate. (3) On heating, copper(II) hydroxide decomposes to yield copper(II) oxide. (4) The copper(II) oxide is combined with concentrated sulfuric acid to yield coppetfll) sulfate. (5) Copper(II) sulfate is treated with an excess of zinc metal to form metallic copper. (6) The remaining zinc metal... 

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