O-Iodosobenzoic acid

Oxidation by the Dess-Martin Reagent. Another reagent that has become important for laboratory synthesis is known as the Dess-Martin reagent,28 which is a hypervalent iodine(V) compound.29 The reagent is used in inert solvents such as chloroform or acetonitrile and gives rapid oxidation of primary and secondary alcohols. The by-product, o-iodosobenzoic acid, can be extracted with base and recycled. 

Hydrolysis with 1.3 M NaOH, resulting in o-iodosobenzoic acid (39) that can be separated by washing with an aqueous sodium bicarbonate solution. 

In this work-up, the periodinane species 38s—resulting from the reduction of Dess-Martin periodinane—is hydrolyzed to o-iodosobenzoic acid,1 which is removed in the basic aqueous solution that is used for hydrolysis. This work-up is suitable for substrates that are not sensitive to aqueous base. 

Several cyclic A3-iodanes of diverse structure have been reported over the years since Victor Meyer s o-iodosobenzoic acid, IBA, whose systematic name is 1 -hydroxy-1,2-benziodoxol-3(lH)-one. A recent review on benziodoxoles presents in detail their preparation and interconversions [51]. In Scheme 13 appears a collection of the main types of A3-iodanes which contain either a benziodox-ole ring or a 5-membered-ring with iodine, oxygen and another atom. 

Many of these iodanes are formed by oxidation of ortho-iodobenzoic acids or certain orf/zo-iodophenylated alcohols with Cl2, AcOOH, f-BuOCl, CF3OF or magnesium monoperoxyphthalate. Among A3-iodanes more important are those derived from o-iodosobenzoic acid which is obtained from the mild oxidation of o-iodobenzoic acid. An improved yield for o-iodosobenzoic acid was obtained by hydrolysis of its acetyl derivative which in turn was prepared from o-iodobenzoic acid and acetyl nitrate in acetic anhydride, at room temperature (Scheme 14) [52]. 

More drastic conditions, i.e. fuming HN03 in (CF3C0)20 were required for the preparation of some zwitterionic pyridinium analogs of o-iodosobenzoic acid (Scheme 15) [53]. 

In the same way 7-chloro-o-iodosobenzoic acid reacted with AgOPO(OPh)2 to provide the O-(diphenylphosphoryl) derivative of o-iodosobenzoic acid [55]. 

Another type of reactivity is due to the enhanced nucleophilicity of the hydroxyl group of o-iodosobenzoic acid. For example, o-iodosobenzoic acid reacts with silyl triflate or other silyl sulfonates to afford O-substituted sulfonates [56]. 

The O-tert-butyloxy derivative of o-iodosobenzoic acid is of interest because of its synthetic utility. In contrast to the facile reaction of tort-butyl hydroperoxide with iodosylbenzene (at - 80 °C), no ligand exchange was observed with this hydroperoxide and o-iodosobenzoic acid, even at room temperature. Treatment of o-iodosobenzoic acid with BF3 Et20, however, provided enough activation for the exchange to take place (Scheme 17) [57]. 

Related compounds are the 7-carboxamido-benziodoxoles which were obtained from o-iodosobenzoic acid upon reaction with trimethylsilyl triflate and the amides (Scheme 28) [78]. Similarly, with trimethylsilyl azide, the azido-analogs were formed as described recently (Scheme 29) [76,79,80]. 

Several solid supports have been employed for the attachment of o-iodosobenzoic acid, including silica gel, titania and nylon [89]. Two polymer-supported o-iodoxybenzoic acid reagents have recently been reported. The first was obtained by attaching a carboxymethyloxy derivative of f-butyl o-iodo-benzoate to an aminopropylated silica gel and oxidation with oxone [90]. The second involved chloromethylated polystyrene which was coupled with methyl 5-hydroxy-2-iodobenzoate and eventually oxidized by Bu4NS05H/MeS03H [91]. Some of these polymeric reagents appear in Scheme 31. 

Alkynyl(aryl)iodonium salts where aryl was the o-carboxyphenyl group were obtained from silylalkynes and o-iodosobenzoic acid [139]. It is noted that the first alkynyl iodonium salts were obtained in low yield from terminal alkynes. This approach was perfected recently, so that a range of substrates upon reaction with p-MeC6H4IO in aqueous HBF4, with catalysis by HgO, afforded alkynyl (tolyl)iodonium salts [140]. 

Mahoney, W. C., and Hermodson, M. A. (1979). High-yield cleavage of tryptophanyl peptide bonds by o-iodosobenzoic acid. Biochemistry 18, 3810-3814. 

For uses of the reagent see Diphenyliodonium-2-carboxylate o-Iodosobenzoic acid. 

Several reports exist on the effect of metal cations on satin hydrolysis (Wagner-Jauregg et al., 1955 Gustafson and Martell, 1962 Epstein and Mosher, 1968). Some of the metal ions that appear to be effective include Cu(ll), Au(ll), Ag(l), Ni(ll), and Zn(ll). The effect of hypochlorite on sarin decomposition has been studied (Epstein et al., 1956), including the effect of surfactant micelles on the process (Dubey et al., 2002). It was shown that the use of cetyltrimethylammonium bromide substantially increased the speed with which satin was destroyed by hypochlorite. The effect of surfactant on the oxidation of sarin (and other OPs) with o-iodosobenzoic acid has been examined (Hammond et al., 1989). As part of an extensive study of the reactivity of nerve agents, Larsson (1958a) conducted a study of hydrogen peroxide s reaction with sarin. 

Hammond, P.S., Forster, J.S., Lieske, C.N., and Durst, H.D. 1989. Hydrolysis of toxic organophosphonis compounds by o-iodosobenzoic acid and its derivatives. Journal of the American Chemical Society, 111 7860-7866. 

Vedejs and Larsen43 describe the preparation of MoOPH and the hydroxylation of the lithium enolate of camphor 265 to give a good yield of a 5 1 ratio of endotexo alcohols 266 while Mori-arty44 gives an example of a method we have not discussed, the hydroxylation of potassium enolates with o-iodosobenzoic acid. 

Add solutions may be used for the preparation of certain naphthalene-sulfonic acids incapable of formation by other means. Both aliphatic and aromatic sulfides or hydrosulfides are oxidized to corresponding sulfonic adds. o-Iodobenzoic acid is oxidized to o-iodosobenzoic acid. 

Amperometric Titrations with Iodine and o>Iodosobenzoic Acid 19... 

Since its introduction as an analytical reagent in this field nearly twelve years ago (73), o-iodosobenzoic acid has been used quite extensively as a rdatively specific reagent for the determination of —SH groups in many substances. As indicated elsewhere, the o-iodosobenzoic acid will not necessarily oxidize all the —SH groups of proteins of native and possibly even of denatured proteins. The specificity is relative and highly dependent on the conditions of operation. Ascorbic acid is oxidized, though slowly. 

N o-iodosobenzoic acid. An accurately weighed amount is dissolved in a slight excess of 1IV KOH and diluted to volume. 

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