Iodinating reagents iodine monochloride

However, in strong hydrochloric acid, these reagents, as weU as iodic acid, oxidize iodine to iodine monochloride or to the ICl ion. 

Iodine monochloride [7790-99-0] ICl, mol wt 162.38, 78.16% I, is a black crystalline soHd or a reddish brown Hquid. SoHd ICl exists ia two crystalline modifications the a-form, as stable mby-red needles, d = 3.86 g/mL and mp 27.3°C and as metastable brownish red platelets, d = 3.66 g/mL, mp 13.9°C and bp 100°C (dec). Iodine monochloride is used as a halogenation catalyst and as an analytical reagent (Wij s solution) to determine iodine values of fats and oils (see Fats and fatty oils). ICl is prepared by direct reaction of iodine and Hquid chlorine. Aqueous solutions ate obtained by treating a suspension of iodine ia moderately strong hydrochloric acid with chlorine gas or iodic acid (118,119). 

Aromatic iodination can be carried out with a number of reagents, including iodine monochloride, 1C1. What is the direction of polarization of IC1 Propose a mechanism for the iodination of an aromatic ring with 1C). 

Introduction of iodine by Sandmeyer processes has been discussed [84AHC(35)83], Direct electrophilic iodination is also observed in the 3-position with reagents such as iodine monochloride, iodine-iodic acid-acetic acid, or molecular iodine. With excess reagent, or when C-3 is blocked, 6-iodination follows [84AHC(35)83 84MI15]. 

Redox titrants (mainly in acetic acid) are bromine, iodine monochloride, chlorine dioxide, iodine (for Karl Fischer reagent based on a methanolic solution of iodine and S02 with pyridine, and the alternatives, methyl-Cellosolve instead of methanol, or sodium acetate instead of pyridine (see pp. 204-205), and other oxidants, mostly compounds of metals of high valency such as potassium permanganate, chromic acid, lead(IV) or mercury(II) acetate or cerium(IV) salts reductants include sodium dithionate, pyrocatechol and oxalic acid, and compounds of metals at low valency such as iron(II) perchlorate, tin(II) chloride, vanadyl acetate, arsenic(IV) or titanium(III) chloride and chromium(II) chloride. 

Iodine monochloride is used as an analytical reagent to determine iodine values of ods and fats. It is dissolved in glacial acetic acid (Wijs solution) for the analysis. ICl is used in organic synthesis. It also is used as a topical antiseptic. 

The iodination of pyrimidines requires the presence of an activating substituent, and is normally performed with reagents such as A -iodosuccinimide (NI8) or iodine monochloride (ICl). A microwave-assisted procedure for the rapid and high-yielding C-5 iodination of substituted pyrimidinones and pyrimidine nucleosides with NIS in dimethylfor-mamide (DMF) has been developed, and thus the iodination of uracil occurred in 98% yield with just 3 min reaction time <200381039>. 

Allyl alcohols readily react with trichloroacetonitrile to give the corresponding trichloroacetimidates 145. Activation of the double bond with electrophilic reagents results in ring closure to yield oxazolines 146. The most commonly employed electrophiles include iodine, iodine monochloride, phenylselenyl chloride, and mercuric trifluoroacetate. Other nitriles including cyanogen bromide and N,N-dimethylcyanamide can also be used. Since oxazolines readily hydrolyze to amides, the net effect of this reaction sequence is to produce p-amino alcohols 147 from an allyl alcohol. This strategy has been employed in numerous total syntheses of natural products. Examples are listed in Table 8.18 (Fig. 8.7 Scheme 8.43). ° ... 

In the case of electrophilic addition, the reactions of tricyclic dienes 1 with several electrophilic reagents have been investigated.1 7 Interestingly, some of these compounds undergo addition reactions with remarkable syn stereoselectivity. For example, the reaction of dimethyl tricy-clo[4.2.2.02,5]deca-3,9-diene-7,8-dicarboxylate with iodine azide solution, prepared in situ from an excess of sodium azide and iodine monochloride, in acetonitrile at — 5 C provided the. yyn-4-azido-3-iodo derivative 2 (Table 1) in 90% yield.1,2,4,6 The formation of the 5,>,n-4-azido-3-iodo derivative 2 is thought to be the first example of a syn addition of iodine azide to an alkene.1,2 The formation of the syn-product is best explained by the twist strain theory,8 according to which the syn transition structure A is favored over the an/7-coplanar transition structure B.1... 

Prostatic acid phosphatase is irreversibly inhibited by reaction with iodine monochloride at pH 8.1. Figures 9 and 10 (60) show the effect of concentration of IC1 and the time course of the reaction. Very rapid inactivation occurred at concentrations of 0.05 vaM IC1. Further increase in the concentration of the reagent produced further inactivation but... 

The reagent in the first step is iodine monochloride, which add to the double bond. 

The authors of this work were able to carry out iodination only when they used iodine monochloride. Compound 233 is unstable when stored in air and loses iodine quite rapidly. We were unable to isolate reaction products in the case of sulfonation with sulpfuric acid. The most convenient sulfonating reagent was a solution of sulfur trioxide in dichlorethane. The sulfonic derivative 234 was very hygroscopic and was further converted into the disodium or bis(isobutylammonium) salt. 

Monosubstitution of the free amine may be achieved by using a less reactive electrophile. Thus aniline and o-toluidine may be mono-iodinated (Expt 6.60) by treatment with iodine (in the presence of sodium hydrogen carbonate or calcium carbonate to remove the liberated hydrogen iodide), the substituent entering the position para to the amino group. Direct iodination can also be effected by using the more powerfully electrophilic reagent, iodine monochloride... 

Elementary chlorine, bromine, and iodine dissolve in many organic solvents, and the variations in the colors among the iodine solutions in various solvents have been a matter of interest to many workers. (Both bromine solutions and solutions of iodine monochloride show analogous variations, but the effect for iodine is by far the most striking.) In completely nonbasic solvents (for example, CCU and CS2) iodine appears violet, the same color as its vapor but as the basicity of the solvent increases, the iodine color shifts toward orange or brown, presumably because the electronic excitation responsible for the iodine color is made more difficult by approach of electron-rich reagents. As the basicity of the solvent increases, the iodine-to-iodine bond weakens in the organic base, pyridine (reaction c, below), many of the I—I bonds are broken, wrhereas... 

The iodine monochloride is an ideal reagent except for the necessity of its handling or preparation. This difficulty has been overcome by the reaction of organoboranes with iodide ion in the presence of mild oxidizing agent chloramine-T 177). The reaction proceeds under extremely mild conditions to afford the corresponding alkenyl iodides (Eq. 115)178) where it can tolerate a variety of functional groups. 

Iodine monochloride, ICl, is another reagent which is useful for the chlorination of alkanes. It was known in the 1950s that IQ was unstable in alkane solution, but the use of irradiation to accelerate the reaction to useful rates was reported later. The chain-carrying step is shown in equation (82). 

Fibrinogen labeled with and Br B-H reagent more suitable than product labeled with I by iodine monochloride, CT, or LP methods for in vivo clearance studies... 

Andrews introduced the titration, further developed by Jamieson," in which potassium iodate is used as a titrating reagent. In 3 to 9 Af hydrochloric acid, iodate is reduced to iodine monochloride ... 

Iodine monochloride is a suitable reagent for oxidations in acid or weakly alkaline solutions. An excess of ICl is added, and a reaction such as the following takes place ... 

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