Iodides preparation

Add 4 0 g. (4 0 ml.) of pure anihne dropwise to a cold solution of ethyl magnesium bromide (or iodide) prepared from 1 Og. of magnesium, 5 0 g. (3-5 ml.) of ethyl bromide (or the equivalent quantity of ethyl iodide), and 30 ml. of pure, sodium-dried ether. When the vigorous evolution of ethane has ceased, introduce 0 02 mol of the ester in 10 ml. of anhydrous ether, and warm the mixture on a water bath for 10 minutes cool. Add dilute hydrochloric acid to dissolve the magnesium compounds and excess of aniline. Separate the ethereal layer, dry it with anhydrous magnesium sulphate and evaporate the ether. Recrystallise the residual anihde, which is obtained in almost quantitative yield, from dilute alcohol or other suitable solvent. 

Perfluoroalkylzinc iodides, prepared in situ from iodides and ultrasonically dispersed Zn, are coupled with allylic halides via an allylic rearrangement[271]. The Pd-catalyzed homocoupling of allylic acetate in the presence of Zn to give a mixture of regioisomers 416 and 417 may proceed via in situ formation of allylzinc species[272,273]. 

Thallium (ITT) fluoride has been prepared by the action of fluorine or bromine trifluoride on thaUium(III) oxide at 300°C. It is stable to ca 500°C but is extremely sensitive to moisture. Thallium (ITT) chloride can be obtained readily as the tetrahydrate [13453-33-3] by passing chlorine through a boiling suspension of HCl in water. It can be dehydrated with thionyl chloride. Thallium (ITT) bromide tetrahydrate [13453-29-7] is prepared similarly, whereas the iodide prepared in this manner is thaUium(I) triiodide [13453-37-7] H" F2-... 

EXAMPLES OF ALKENXL IODIDE PREPARATION FROM CARBO-CUPRATION... 

Anhalonine and Lophophorine. Spath and Gangl showed that each of these alkaloids contains a methylenedioxy group and that the quarternary iodide prepared from dZ-anhalonine is identical with lophophorine methiodide so that lophophorine must be N-methylanhalonine. Anhalonine was synthesised from 3 4-methylenedioxy-5-methoxybenzaldehyde by condensation with nitromethane, reduction of the product to the corresponding -ethylamine, the acetyl derivative (VII) of which, on treatment with phosphoric anhydride, condensed to 6-methoxy-7 8-methylenedioxy-l-methyl-3 4-dihydrofsoquinoline, m.p. 60-2°. This, on reduction, furnished the corresponding tetrahydrofsoquinoline, which proved to be anhalonine (VIII), and on conversion to the quaternary methiodide the latter was found to be lophophorine (IX) methiodide. The possible alternative, 8-methoxy-6 7-methylenedioxy-l 2-dimethyl-l 2 3 4-tetrahydrofsoquinoline, was prepared by Freund s method and the methiodide shown not to be identical with lophophorine methiodide. 

To an ethereal solution of methyl magnesium iodide prepared from 26.7 g (1.1 mols) of magnesium and 160 g (1.13 mols) Of methyl iodide in 200 cc of dry ether, is added a solution of 79 g (0.72 mol) of cyclopentylacetonitrile in 100 cc of dry ether. The reaction mixture is refluxed for 4 hours. The reaction mixture is then decomposed with ice in the usual way, and the ether layer containing the cyclopentylacetone is separated, is dried over anhydrous magnesium sulfate and the ether removed by evaporation. The residue comprising cyclopentylacetone is purified by distillation in vacuo. The cyclopentylacetone boils at 82° to 84°C at about 32 mm pressure. 

Iodide. A 0.01 M solution of potassium iodide, prepared from the dry salt with boiled-out water, is suitable for practice in this determination. The experimental details are similar to those given for bromide, except that the indicator electrode consists of a silver rod immersed in the solution. The titration cell may be charged with 10.00 mL of the iodide solution, 30 mL of water, and 10 mL of the stock solution of perchloric acid + potassium nitrate. In the neighbourhood of the equivalence point it is necessary to allow at least 30-60 seconds to elapse before steady potentials are established. 

For the corresponding bromides and iodides, preparation starts with K2PtX4 (X = Br, I) formed in situ from PtCl - with KX. For trans-Pd(PR3)2Cl2, shaking alcoholic PdCl2 or Na2PdCl4 with the phosphine yields a solution of the yellow complex. 

The novel highly substituted spiro[4.4]nonatrienes 98 and 99 are produced by a [3+2+2+2] cocyclization with participation of three alkyne molecules and the (2 -dimethylamino-2 -trimethylsilyl)ethenylcarbene complex 96 (Scheme 20). This transformation is the first one ever observed involving threefold insertion of an alkyne and was first reported in 1999 by de Meijere et al. [81]. The structure of the product was eventually determined by X-ray crystal structure analysis of the quaternary ammonium iodide prepared from the regioisomer 98 (Ar=Ph) with methyl iodide. Interestingly, these formal [3+2+2+2] cycloaddition products are formed only from terminal arylacetylenes. In a control experiment with the complex 96 13C-labeled at the carbene carbon, the 13C label was found only at the spiro carbon atom of the products 98 and 99 [42]. 

Ethy 1-2,4-dime thylselenazolsum iodide, preparation, intermediates for cyanine dyes, 256... 

The general utility of the oxidative addition of functionalized organic halides to zinc was demonstrated by the formation of organozinc iodides 28 from protected (3- and 7-amino acids (Scheme 26).73 The organozinc iodides prepared in this manner were neither sufficiently stable nor sufficiently reactive in THF, but excellent yields were obtained in more polar aprotic solvents, such as DMF and DMSO. 

Method E (-)-A-methylquininium iodide, (+)-A-methylquinidinium iodide, (-)-N-methylcinchonidinium iodide, and (+)-/V-mcthylcinchoninium iodide, prepared by... 

A more recent report describes the regio- and stereoselective addition of aryltellurenyl iodides (prepared in situ from the corresponding ditellurides and iodine) to alkynes to afford the ( )-l-iodo-2-aryltelluro-l-alkenes, which treated with bromine give the corresponding dibromides. ... 

A one-pot reaction of phenylacetylene with a dialkyl ditelluride and an alkyl iodide under phase transfer catalysis (method a). The same product can be obtained by using the tellurenyl iodide prepared in situ (method b). ... 

Cerium(III) iodide prepared in situ from an aqueous solution of ceric sulfate first by reduction with sulfur dioxide followed by sodium iodide reduced a-bromoketones to ketones in 82-96% yields [212]. 

Milder reductions with hydriodic acid can be accomplished by using more dilute hydriodic acid, or solutions of hydrogen iodide prepared from alkaline iodides and hydrochloric or acetic acid in organic solvents [22S],... 

Reaction of Sodium Chloride, Sodium Bromide, and Potassium Iodide with Concentrated Sulphuric Acid. Put three test tubes on a stand. Put a little sodium chloride in the first of them, sodium bromide in the second, and potassium iodide in the third. Pour several drops of concentrated sulphuric acid into each tube handle the acid with a pipette or tube having a rubber bulb ). What do you observe What impurities do hydrogen bromide and iodide prepared in this way contain Write the equations of the reactions. 

Preparation of Mercury(II) Iodide. Prepare a 0.02 N solution of mercury(II) nitrate. Boil 2-3 ml of the solution, add an equal volume of a 0.02 N potassium iodide solution, and let the mixture stand to your next lesson. Filter off the precipitate (what is its composition ) through a paper filter, wash it with water, and dry it in a drying cabinet at 70 °C. What happens to the salt when it is kept in the air ... 

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