Esters iodination

Nitroisophthalic acid, dimethyl ester Iodine monochloride... 

In Lipid (%) In Tissue (%) Ester Iodine Value In Lipid (%) In Tissue (%) Ester Iodine Value... 

A closely related reaction is equilibration of a dicarboxylic acid and its diester to produce monoesters The reaction of a carboxylic acid with ethyl acetate, in the presence of NaHS04 Si02, was shown to give the corresponding ethyl ester. Iodine catalyzes the transesterification of p-keto esters. 

Intramolecular cyclopropanation Malonic esters of certain allylic alcohols form bicyclic lactones by way of iodination and generation of carbene intermediates. Thus when the system containing the malonic ester, iodine, solid K2CO3 and tri-caprylmethylammonium chloride in toluene is heated, the reaction occurs. 

A similar sequence of reactions was described to account for the behaviour of the same phosphinothioate ester with bromine or with iodine The intermediates including, for the brominolysis, those with two phosphorus atoms appeared to be more stable at room temperature. In the case of iodination, no phosphinic iodide was formed, and the only products that were detected were the ester-iodine complex(es) and the iodide of 146 further reaction, which took 1-2 months, gave the thiopyrophosphinate 148 complexed with iodine, as in 149. The bromination reaction was also slow, and although the complex 149 (X = Br) could readily be detected during shorter reaction periods, di- rNbutylphosphinic bromide was obtainable in yields of about 30% only when admixed S -methyl di-f r -butylphosphinothioate and bromine were stored at room temperature for about 2 months. 

Indole and derivatives Insecticides —, chlorine-containing —, thiophosphate esters Iodine-containing compounds... 

It is however more complicated, esters of phosphorous acid being also formed (c/. p. 308). Iodides are usually prepared by a modification of this method, the ethanol being mixed with red phosphorus, and iodine added. The phosphorus iodide is thus formed in situ, and at once reacts with ethanol to give the corres ponding iodide. 

When an ethanolic solution of the sodium derivative of ethyl malonate is. shaken with a solution of iodine, the latter withdraws the sodium, and the ethyl malonate residues link together in pairs to give the tetra-ethyl ester of... 

Magnesium iodide is soluble in alcohols and many other organic solvents, and forms numerous addition compounds with alcohols, ethers, aldehydes, esters, and amines. One example is magnesium iodide dietherate [29964-67-8], Mgl2 prepared by gradual addition of iodine to a... 

Composition. Shellac is primarily a mixture of aUphatic polyhydroxy acids in the form of lactones and esters. It has an acid number of ca 70, a saponification number of ca 230, a hydroxyl number of ca 260, and an iodine number of ca 15. Its average molecular weight is ca 1000. Shellac is a complex mixture, but some of its constituents have been identified. Aleuritic acid, an optically inactive 9,10,16-trihydroxypalmitic acid, has been isolated by saponification. Related carboxyflc acids such as 16-hydroxy- and 9,10-dihydroxypalmitic acids, also have been identified after saponification. These acids may not be primary products of hydrolysis, but may have been produced by the treatment. Studies show that shellac contains carboxyflc acids with long methylene chains, unsaturated esters, probably an aliphatic aldehyde, a saturated aliphatic ester, a primary alcohol, and isolated or unconjugated double bonds. 

Trimethylsilyl iodide [16029-98-4] (TMSI) is an effective reagent for cleaving esters and ethers. The reaction of hexamethyldisilane [1450-14-2] with iodine gives quantitative conversion to TMSI. A simple mixture of trimethylchlorosilane and sodium iodide can be used in a similar way to cleave esters and ethers (8), giving silylated acids or alcohols that can be Hberated by reaction with water. 

Titration of thioglycolate esters is also realized by iodine in alcohoHc solution. Titration of thioglycolic acid (acid number) in thioglycolate esters is effected by potentiometric titration with potassium hydroxide. 

Bayberry Wax. Bayberry wax [8038-77-5] is removed from the surface of the berry of the bayberry (myrtle) shmb by boiling the berries in water and skimming the wax from the surface of the water. The wax is green and made up primarily of lauric, myristic, and palmitic acid esters. The wax has a melting point of 45°C, an acid number of 15, a saponification number of 220, and an iodine number of 6. The wax has an aromatic odor and is used primarily in the manufacture of candles and other products where the distinctive odor is desirable. 

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. 

Hyperthyroidism may be treated in several ways. One of these is interference with the synthesis of the thyroid hormones, possibly by removal of iodine. Thiourea and cyclic thioureas have this effect and of such cyclic compounds, thiouracil (1030 R = H), its 6-alkyl derivatives (1030 R = Me or Pr) and thiobarbital (1031) are effective thyroid drugs. Today only propylthiouracil (1030 R = Pr) is widely used, probably because it has fewer side effects than the others (71MI21302). The thiouracils are made by the Principal Synthesis from a /3-oxo ester (1032 R = H, Me, Pr, etc.) and thiourea (45JA2197) their fine structures are experimentally based (64AF1004). 

Dioxopiperazines are amongst the most ubiquitous of natural products (75FOR(32)57) and they are formally derived by the cyclodimerization of a-amino acids (69CCC4000) or their esters. A number of methods are available for their oxidation to the corresponding pyrazines. Treatment of 2,5-dioxopiperazines with triethyl- or trimethyl-oxonium fluorobor-ate followed by oxidation with DDQ, chloranil or iodine results in pyrazine formation, usually in high yields (Scheme 63) (72JCS(P1)2494). 

Acrylic acid, -(3-benzo[f>]thienyl)-a -mercapto-reaction with iodine, 4, 764 Acrylic acid, o -cyano-y3-(2-thienyl)-ring opening, 4, 807 Acrylic acid, -formyl-in pyridazinone synthesis, 3, 46 Acrylic acid, furyl-rotamers, 4, 545 synthesis, 4, 658 Acrylic acid, 2-hydroxybenzoyl-chroman-4-one synthesis from, 3, 850 Acrylic acid, 5-(l-propynyl)-2-thienyl-methyl ester occurrence, 4, 909 Acrylonitrile... 

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