3-Iodophenol

The p-iodophenol solidifies upon cooling. The yield of material melting at 32-340 is 70 g. (63 per cent of the theoretical amount). The product obtained in this way is slightly yellow. If a purer product is desired, it may be redistilled in vacuo. 

Most of the crude material will distil over a 5-degree range (b.p. 130V18 mm. and i86°/i6o mm., m.p. 43°). 

About 460 cc. of chloroform can be recovered, the time required being one hour. 

The first distillation of the iodophenol should be carried out under a good vacuum, 40 mm. or lower. The redistillation may be conducted at a higher pressure if desired. 

Since the iodophenol has a most persistent odor, care should be exercised in working with it. A solution of bromine in glycerol may be used as an antidote for burns from the iodophenol (p. 14). 

One hundred and nine grams (1 mole) of -aminophenol (Note 1) is dissolved in a mixture of 500 g. of ice, 500 cc. of water, and 65 cc. (120 g., 1.2 moles) of concentrated sulfuric acid (sp. gr. 1.84). To this solution, kept in a freezing mixture at o°, is added during the course of an hour with constant mechanical stirring, a solution of 72 g. (1 mole) of 95 per cent sodium nitrite in 150 cc. of water. The stirring is continued twenty minutes longer, and then 20 cc. (37 g., 0.37 mole) of concentrated sulfuric acid is added. 

This solution is poured into an ice-cold solution of 200 g. (1.2 moles) of potassium iodide in 200 cc. of water. After a few minutes, 1 g. of copper bronze (Note 2) is added, with continued stirring, and the solution is warmed slowly on the water bath. The temperature is kept at 75-80° until the evolution of nitrogen ceases during this process the iodophenol separates as a heavy dark oil. After cooling to room temperature the reaction mixture is extracted three times with 165-cc. portions of chloroform and the combined extracts washed with dilute thiosulfate solution. The solvent is removed on the water bath and the residue distilled under reduced pressure, the / -iodophenol coming over 

The /j-aminophcnol used was a commercial product melting at 18 2-183° with decomposition. 

Some commercial bronzes used for bronze paints are coated with a film of stearic acid. For chemical work an untreated pure copper bronze should be used. 

8 Griess, Zeit. fur Chemie, 1865, 427 Holleman and Rinkes, Rec trav. chim 30, 95 (1911). 

Moat phenols are crystalline solids notable exceptions are m-cresol and o-bromophenol. The monohydric phenols generally have characteristic odours. The solubihty in water increases with the number of hydroxl groups in the molecule. 

An alternative procedure, more suitable for the preparation of somewhat larger quantities of the bromo derivative, is the following. Dissolve 10 g, of the compovmd in 10-15 ml. of glacial acetic acid, cautiously add 3-4 ml. of hquid bromine, and allow the mixture to stand for 15-20 minutes. Pour into 50-100 ml. of water, filter off the bromo compound at the pump, and wash with a httle cold water. Recrystallise from dilute alcohol. 

Place in a dry test-tube 0 -5 g. of the compound and an equal bulk of pure phthahc anhydride, mix well together, and add 1 drop of concentrated sulphuric acid. Stand the tube for 3-4 minutes in a smah beaker of concentrated sulphuric acid or oil previously heated to 160°, Remove from the bath, allow to cool, add 4 ml. of 5 per cent, sodium hydroxide solution and stir until the fused mass has dissolved. Dilute with an equal 

Acetates. The acetates of monohydric phenols are usually liquids, but those of di and tri-hydric phenols and also of many substituted phenols are frequently crystaUine sohds. They may be prepared with acetic anhydride as detailed under Amines, Section IV,100,7. 

Acetates may also be prepared by adding acetic anhydride to somewhat dilute solutions of compounds containing hydroxyl (or amino) groups in aqueous caustic alkahs. The amount of alkali used should suffice to leave the hquid shghtly basic at the end of the operation, so much ice should be added that a little remains unmelted, and the acetic anhydride should be added quickly. 

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Chemiluminescence and bioluminescence are also used in immunoassays to detect conventional enzyme labels (eg, alkaline phosphatase, P-galactosidase, glucose oxidase, glucose 6-phosphate dehydrogenase, horseradish peroxidase, microperoxidase, xanthine oxidase). The enhanced chemiluminescence assay for horseradish peroxidase (luminol-peroxide-4-iodophenol detection reagent) and various chemiluminescence adamantyl 1,2-dioxetane aryl phosphate substrates, eg, (11) and (15) for alkaline phosphatase labels are in routine use in immunoassay analyzers and in Western blotting kits (261—266). 

It was mentioned earlier (Sec. 8.6) that for iodo-de-diazoniation no catalyst is necessary because the redox potential of the iodide ion (E° = 1.3 V) is sufficient for an electron transfer to the arenediazonium ion. The reaction was actually observed by Griess (1864 c). Four iodo-de-diazoniation procedures are described in Organic Syntheses. For the syntheses of iodobenzene and 4-iodophenol (Lucas and Kennedy, 1943, and Daines and Eberly, 1943, respectively) KI is used in equimolar quantity and in 1.2 molar excess. However, for 2-bromoiodobenzene and for 1,3,4-triiodo-5-nitrobenzene (replacement of a diazonio group in the 4-position by iodine), up to... 

A copper salt assists the control of the regioselectivity in VNS for m-dinitrobenzene. For instance, the reaction of m-dinitrobenzene with 4-iodophenol in the presence of copper tert-butoxide gives asymmetrical biphenyl in 78% yield (Eq. 9.34).61... 

FIGURE 5.7 Effects of binary and ternary gradient elution with methanol and acetonitrile on separation selectivity in RP HPLC. Column LiChrosorb RP-C18, 5 pm, 300x4.0mm i.d. flow rate ImL/min UV detection, 254nm. Sample 4-cyanophenol (1), 2-methoxyphenol (2), 4-fluorophenol (3), 3-fluorophenol (4), 3-methylphenol (5), 4-chlorophenol (6), 4-iodophenol (7), 2-phenylphenol (8), and 3-ferf-butylphenol (9). 

Iodophenol on alumina Hypoiodous acid Charcoal or silver zeolite Organic. 

The synthesis of 1 as described in Scheme 10.2 relies on monolithiation of 9, which is not always easy to reproduce. In order to avoid this problematic step, Bryce and coworkers [13f] developed an alternative synthesis based on four high-yielding steps. The synthesis starts from 4-iodophenol 11, which was reacted... 

Iodophenol, immobilized on a polystyrene-Wang resin, has been treated with a series of arylboronic acids dissolved in [C imJfBFJ using Pd(PPh3)4 as the palladium source (Scheme 5).47 The catalytic system was initiated in a similar manner to that previously reported45 and the reactions conducted at 110°C for 2 h. A 1 1 mixture with DMF was required to swell the hydrophobic cross-linked polystyrene resin and when neat [C4mim][BF4] was used no biaryl products were isolated. 

Scheme 5. Ionic liquid mediated solid-phase Suzuki reaction of immobilized 4-iodophenol.

The effect of the halogen substituent (fluoro, chloro, bromo and iodo) on the yield and mechanism of 4-halophenol photolysis was investigated by Durand et al. [24], Transient spectroscopy in aerated aqueous solutions indicated the formation of p-benzoquinone O-oxide from each derivative except 4-iodophenol for which no transients were detected p-benzoquinone and hydroquinone were found as photoproducts for all four compounds. It was concluded that the carbene mechanism was valid for the whole series. Under continuous irradiation, the 4-halophenol degradation quantum yields were determined to be

fluorescence lifetimes decreased in the same order, from 2.1 ns for 4-fluorophenol to 0.4 ns for 4-chlorophenol and < 0.1 ns for 4-bromophenol. 

CjCqmHBFJ Pd(PPh3)4 Na2C03 110 °C. Solid-phase reaction coupling of 4-iodophenol immobilised on a polystyrene-Wang resin with arylboronic acids DMF as co-solvent acceleration in the presence of the ionic liquid catalyst recycling not practical. [102]... 

A mixture of phenol and cyclodextrin in 20% sodim hydroxide at 2C was treated with iodine in 10% sodium iodide solution and stirred Ih. to give 4-iodophenol. 

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