Hypohalous acids, HOX

This section concludes with a reminder that, in addition to the hypohalous acids HOX and metal hypohalites M(OX) , various covalent (molecular) hypohalites are known. Hypochlorites are summarized in Table 17.22. All are volatile liquids or gases at room temperature and are discussed elsewhere (see Index). Organic hypohalites are unstable and rapidly expel HX or RX to form the corresponding aldehyde or ketone ... 

In general, fluorine has a formal oxidation state of — 1, but in HOF and other hypohalous acids HOX, the formal oxidation state of F and X is +1. 

Sec. 7.3) from alkenes by electrophilic addition of hypohalous acid (HOX)... 

Bromine oxide species can be formed in the polar boundary layer and areas with high salt levels such as the Dead Sea." ° The major source of gas-phase bromine in the lower troposphere is thought to be the release of species such as IBr, ICl, Br2 and BrCl from sea-salt aerosol, following the uptake from the gas phase and subsequent reactions of hypohalous acids (HOX, where X = Br, Cl,... 

There is evidence, of a kind we are not prepared to go into here, that these compounds are formed by reaction of halogen and water (as shown in Sec. 6.13) rather than by addition of preformed hypohalous acid, HOX. Whatever the mechanism, the result is addition of the elements of hypohalous acid (HO— and —X), and the reaction is often referred to in that way. 

Table 16.5 lists the families of oxoacids known for Cl, Br and I. The hypohalous acids, HOX, are obtained in aqueous solution by reaction 16.57 (compare reactions 16.40 and 16.42). 

The main electrophilic reagents concerned in halogenation reactions are the neutral molecules Xg (or XY), positively charged species, such as X+ or XOH2+, and the hypohalous acids, HOX. Since different mechanisms involving different electrophilic species can operate in the same system, a subdivision of this section based on the nature of the halogen (chlorination, bromination, iodination) has been preferred to that based on the type of electrophilic species. 

In addition to the radical-dependent mechanism of lipid oxidation described above, unsaturated lipids (as indeed many other types of biomolecule) can also be modified by electrophilic compounds that add across double bonds. The most commonly known oxidants that carry out such reactions are hypohalous acid (HOX), such... 

FIGURE 4.2 Sequential targeting of plasmalogen reactive sites by hypohalous acids. Hypohalous acids (HOX) first target the vinyl ether bond of plasmalogens and then the alkene of the sn-2 aliphatic group of unsaturated molecular species of lysophosphatidylcholine. 

Figure 1.57 Reaction mechanisms of heme-type haloperoxidases showing the formation hypohalous acids (HOX X = Cl, Br, or I).

Numerous reports detailed NMR and XRD studies of ylide structures and conformations.In addition, the molecular interactions between phosphorus ylides and hypohalous acids HOX (X = F, Cl and Br) were investigated from a theoretical standpoint. ... 

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