Ketones iodination

Five simple a-diols have been successfully cleaved by N-iodosuccinimide (NIS) in THF at ambient temperature. Products from the oxidation are aldehydes, ketones, iodine and succinimide. Irradiation of the reaction increases the cleavage rate, indicating a radical pathway. Its attractiveness is its simplicity of... 

Hypoiodites are used for qualitative tests for methyl ketones (Lieben test). For this purpose, a compound to be tested is stirred with an aqueous solution of sodium hydroxide (80 mol/mol of methyl ketone). Iodine (4.5 mol of 12) is added portionwise with stirring, and the mixture is set aside for 20 min at 25 °C before acidification. In the presence of a methyl keto group, a yellow heavy precipitate of iodoform settles at the bottom of the test tube. Iodoform can be identified easily not only by its characteristic smell but also by its melting point (120-123 °C) [1173], This test applies not only to methyl ketones but to any compound that can be converted in the reaction medium into a species containing the COCH3 group, for example, isopropyl or ethyl alcohol. 

Use Reduction of various organic compounds purification of aldehydes and ketones, iodine, sodium hydrosulfite antiseptic source of sulfurous acid, particularly in brewing analytical chemistry tanning bleaching straw and textile fibers chemical preservative in foods (except meats and other sources of vitamin B,). 

The use of a-halogenoketones for cyclizing 2-aminoazines or 2-aminoazoles is well-known (see p. 276 and [B-45, 3533]), but the same result may be obtained by heating the heterocycle with a ketone, iodine or bromine and sodium hydro-gencarbonate in ethanol [2710]. In an extension of the reaction of 2-amino-thiazoles with a-bromoketones (p. 277), 1-bromomethyl 2-t-butyl ketone has been shown to give high yields of 6-t-butylimidazo[2,I-6]thiazoles, the presence... 

Foster, J. and Goldstein, M. (1968) Spectroscopic studies of some aryl ketone-iodine complexes. Spectrochim. Acta, Part A, 24A, 807-812. 

This latter method consists in treating 2 moles of thiourea and 1 mole of ketone, having a methylene group adjacent to the carbonyl, with 1 mole of iodine overnight on a steam bath. Unreacted products are then extracted with ether after alkalinization of the reaction mixture. 

Aminolhtazoles were synthetized from thiourea by three methods Method A, from a-haloketones or aldehydes designated as (Cl) or (Br) Method B, from ketones and iodine (fj) or bromine (Btj) Method C, from iodomercuriketones. Method D consists in condensing ketones with cyanamid and sulfur. 

Various electrophiles other than iodine have been used to induce alkenyl coupling (9). Alkyl haUdes and protic acids react with alkynylborates to yield mixtures of stereoisomeric alkenylboranes. Nevertheless, oxidation of these products is synthetically useful, providing single ketones (296—298). Alcohols are obtained from the corresponding alkenylborates. 

The butanals form the conventional aldehyde hydra2one, semicarba2one, and dimedone-type derivatives. In the absence of other aldehydes and ketones, -butyraldehyde can be deterrnined by addition of sodium bisulfite and the excess bisulfite deterrnined with iodine or thiosulfate (34). 

Molecular Interactions. Various polysaccharides readily associate with other substances, including bile acids and cholesterol, proteins, small organic molecules, inorganic salts, and ions. Anionic polysaccharides form salts and chelate complexes with cations some neutral polysaccharides form complexes with inorganic salts and some interactions are stmcture specific. Starch amylose and the linear branches of amylopectin form inclusion complexes with several classes of polar molecules, including fatty acids, glycerides, alcohols, esters, ketones, and iodine/iodide. The absorbed molecule occupies the cavity of the amylose helix, which has the capacity to expand somewhat to accommodate larger molecules. The starch—Hpid complex is important in food systems. Whether similar inclusion complexes can form with any of the dietary fiber components is not known. 

Oxidation of methyt ketones with hypochtoiide (or hypobromde) to caitwxylic adds and chloioform with NaOH arxf iodine lodofoim is foimed... 

Rates of enolization can be measured in several wt s. One method involves determining the rate of halogenation of the ketone. In the presence of a sufficient concentration of bromine or iodine, halogenation is much faster than enolu ation or its reverse and can therefore serve to measure the rate of enolization ... 

Obtain the TLVs for the following chemicals carbon tetrachloride, chlorobenzene, iodine, ethyl formate, phenol, methanol, and MEK (methyl ethyl ketone). Rank these in order of greatest health risk. Here s a chance for you to become acquainted with some of the Web sites referred to earlier. 

The isotopic purity of the product is usually about 48-62%, the rest of the material being mainly undeuterated. (An alternate preparation of a-mono-deuterio ketones of high configurational and isotopic purity is the mild oxidation of cis- or tra 5-deuterated alcohols under Jones conditions, see sections V-D and VII-A.) Treatment with zinc in acetic acid-OD has also been applied to the deiodination of 2a-iodoandrost-4-ene-3,17-dione. In a slightly modified version the iodine in 19-iodocholesterol acetate has been replaced with tritium by using tritium oxide as the isotope source/... 

However, treatment of cortisone 3,20-bissemicarbazone with acetic anhydride and pyridine removes the 20-semicarbazone group preferentially. Selective removal of a protecting group can be also achieved by a selective reaction to give a new intermediate which can be converted into the desired product ketone. Thus progesterone 20-monoenol acetate (42) is prepared from the 3,20-bisenol acetate (40) via selective electrophilic attack of iodine at C-6 followed by reductive dehalogenation of (41). ... 

The homolysis of tertiary hypochlorites for the production of oxy radicals is well known." The ease with which secondary hypohalites decompose to ketones has hampered the application of hypohalites for transannular reactions. However the tendency for the base-catalyzed heterolytic decomposition decreases as one passes from hypochlorites to hypobromites tohypoidites. Therefore the suitability of hypohalites for functionalization at the angular positions in steroids should increase in the same order. Since hypoidites (or iodine) do not react readily with ketones or carbon-carbon double bonds under neutral conditions hypoiodite reactions are more generally applicable than hypochlorite or hypobromite decompositions. 

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