Deamination molecular mechanics

In the presence of molecular oxygen, D-arabinose (82) is the major deamination product. D-tfrafeino-Hexos-2-ulose (79) is also formed, but the formation of 2-deoxy-D-hexonic acid (80) and 2-deoxy-D-ert/fhro-hexos-3-ulose (81) is suppressed. It has been suggested34 that the peroxyl radical derived from the W-centered radicals (78) may be, in part, the precursor of D-arabinose. A mechanism similar to the... 

The reaction of a-ketodiazonium ions is of interest because there is considerable evidence that loss of nitrogen can occur by an 8 2 mechanism (p. 337-347). If this is generally true, the possibility arises of a comparison between the reactions of diazonium ions and those of alkyl halides and tosylates under conditions that do not lead to the formation of carbonium ion intermediates. In the discussion of the molecularity of the rate-determining step, the reaction of ketodiazonium ions was supposed to proceed with simple substitution by an external nucleophile. Product analyses, on the reactions of diazoketones with acids and the deamination of aminoketones, show, however, that extensive rearrangement and molecular fragmentation can occur in suitable alkyl structures. The simplest of these reactions have the following stoichiometric form (Baumgarten and Anderson, 1961) ... 

It was found that the major mechanism in radiolysis of diaminobutyric acid in oxygenated solution is oxidative deamination on < - or y-position. This is clear from a comparison of the decrease in the content of diaminobutyric acid (G/-M/2.65), with the yield of ammonia (G 2.1) and with the yields of deaminated products (S G 2.0). Aside from carbonyl substances and ketoamino acids, /2-alanine and aspartic acid have been found among the products of oxidative deamination. In oxygen-free atmosphere, two of the main radiation mechanisms are reductive deamination (G/-M/1.4 and G NH3 1.2) and recombination reactions leading to products of higher molecular weight. 

---