Hypoiodites preparation

The difficulty associated with the preparation of the starting materials for these carbonium ion reactions decreases their general utility for the preparation of protoadamantyl derivatives. A recently reported isomerization of the 1-adamantyloxy radical conveniently overcomes this problem. Thermolysis of 1-adamantanol hypoiodite, prepared in situ in dry benzene, gives endo-3-iodomethylbicyclo [3.3.1 ] nonane-7-one, which, when treated with base, gives 4-protoadamantanone (Eq. (22)) in an overall yield from 1-adamantanol of approximately 30 % 79,79af... 

Lactose is oxidized by hypoiodite, prepared from iodine and alkali, to give lactobionic acid. Under carefully controlled conditions, the reaction is stoichiometric and can be used for the quantitative determination of lactose on a micro scale by measurement of the iodine consumed. At pH 10.6, lactose is oxidized at a rate 0.81 times that observed for o-glu-cose. ... 

A convenient method for generating the alkoxy radical is by fragmentation of hypoiodites prepared in situ from the corresponding alcohol. This can be accomplished by treatment of the alcohol with iodine and lead tetraacetate or mercury(II) oxide, or with iodine with iodobenzene diacetate. For example, irradiation of the alcohol 29 under these latter conditions gave a high yield of the tetrahydrofuran 30 (4.29). In another apphcation of this chemistry, for the specific deprotection of benzyl ethers, irradiation of the alcohol 31 and A-iodosuccinimide (NIS) gave the cyclic acetal 32 (4.30). ... 

A mixture of cyclohexyl methyl ketone and a soln. of Na-hypoiodite (prepared from iodine, NaOH, KI, and water) containing 3 times the theoretical amount of alkali warmed 4 hrs. at 50-60° with vigorous stirring cyclohexylglycolic... 

A light-induced reaction of steroidal hypoiodites prepared by the reaction of a steroidal alcohol with iodine oxide generated from mercury(ll) oxide-iodine generally gives a five-membered oxide, which should be formed by an intramolecular Sfj2 or S 2 reaction of intermediate 19-iodide, as outlined in Scheme 15. 

Functionalized bicyclo [x.y.0] alkanes (x = 5 or 6 y = 7 or 8) can be synthesized by the irradiation of hypoiodites prepared by [2+2] -photoaddition of cyclic enones with the trimethylsilyl enol ethers of cycUc ketones (as outlined in general in Scheme 70). Scheme 71 outlines the new total synthesis of ( )-a-himachalene based on this method as the key step. ... 

A soln. of cyclohexane and ferf-butyl hypoiodite (prepared from erf-butyl hypochlorite and mercuric iodide in CCI4 irradiated at 40° in a degassed sealed Pyrex ampoule cyclohexyl iodide. Y 71% by gas-liq. chromatography. -Tert. hydrogen could not be replaced. F.e. s. D. D. Tanner and G. C. Gidley, Am. Soc. 90, 808 (1968). 

The procedure described here is a modification of one involving the thermal fragmentation of 1-adamantyl hypoiodite and cycliza-tion of the resulting iodo ketone/ By means of this procedure, 4-protoadamantanone is obtained from 1-adamantanol with consistent yields in the range of 71 to 82% and a purity greater than 98%. This method is also applicable to the preparation of other polycyclic ketones from the related bridgehead alcohols with a-bridges of zero, one, or two carbon atoms (see Table I). 

Lactones by ring expansion of lactols. Medium-sized lactones can be obtained in reasonable yield by photolysis of the hypoiodites of catacondensed lactols, which results in regioselective cleavage of the bridging bond. The substrates are available by the general route shown for the 6/6 lactol 1, which is cleaved to the 10-membered lactone 2. This cleavage can be used for preparation of 9-membered... 

The procedure described here allows for a convenient and efficient preparation in very high yields of large quantities of bromides from carboxylic acids containing an olefinic functionality. The Hunsdiecker reaction is traditionally accomplished by treating anhydrous silver carboxylates with bromine or iodine.2 Heavy metal salts such as mercury,3 lead,4 and thallium5 have also been used successfully as well as tert-butyl hypoiodite.6 The major disadvantages associated with the above methods, such as use of heavy metal salts and non-tolerance towards olefins, has led to the development of a more versatile method using O-acyl thiohydroxamates.7 8 The O-... 

The preparation of the title lactone has been described by a multistep synthesis from holarrhimine. The method described in detail above is essentially an application of the hypoiodite reaction published by Ch. Meystre and co-workers. These authors also describe the isolgition of the intermediate hemiacetal in pure form. Saturated lactones epimeric at C-20 have also been obtained by chromic acid oxidation of 18,20-dihydroxy compounds which were in turn prepared by treatment of 20-hydroxypregnanes with lead tetraacetate, acetolysis of the resulting 18,20 3-oxides, and hydrolysis. Saturated lactones of the... 

The synthesis of the four monocarboxylic acids of dibenzothiophene has been recorded in the previous review. However, several modified preparations have since been described. Ethyl 1-dibenzothiophene-carboxylate has been synthesized from 2-allylbenzo[6]thiophene (Section IV,B, 1) hydrolysis afforded the 1-acid (57% overall). In a similar manner, 3-methyl-1-dibenzothiophenecarboxylic acid was obtained from the appropriately substituted allyl compound. This method is now the preferred way of introducing a carbon-containing substituent into the 1-position of dibenzothiophene. 2-Dibenzothiophenecarboxylic acid has been prepared by oxidation of the corresponding aldehyde or by sodium hypoiodite oxidation of the corresponding acetyl compound. Reaction of 2-acetyldibenzothiophene with anhydrous pyridine and iodine yields the acetyl pyridinium salt (132) (92%), hydrolysis of which yields the 2-acid (85%). The same sequence has been carried out on 2-acetyldibenzothiophene 5,5-dioxide. The most efficient method of preparing the 2-acid is via carbonation of 2-lithio-... 

C. F. Schonbein also prepared ammonium hypobromite by a process analogous to that employed for the hypochlorite, and obtained a liquid with similar oxidizing properties. The liquid is assumed to contain a mixture of ammonium hypobromite and bromide. C. F. Schonbein likewise inferred the transient formation of ammonium hypoiodite when iodine water and aqueous ammonia are mixed, whereby the liquid is decolorized. The soln. gave a deep blue coloration with starch paste and potassium iodide, etc., and behaved like analogous soln. of the alkali... 

A. J. Balard 8 prepared an olive-green insoluble mass by the action of bromine water on copper oxide, vegetable colours are not bleached, but nitrogen is evolved from ammonia, and carbonic and other acids set free bromine. When heated, oxygen, bromine, and water are given off, and copper oxybromide remains. The solid is possibly a mixture of bromine and copper oxybromide and not copper hypobromite. A. J. Balard also prepared a soln. which probably contained silver hypobromite by the action of bromine water on silver oxide. The product easily decomposes into bromide and bromate. F. W. Schmidt suggested that the white floccuient precipitate obtained by the action of iodine on a very dil. ammoniacal soln. of silver nitrate is possibly silver hypoiodite. 

A. J. Balard found mercury immediately decomposes hypochlorous acid without the disengagement of any gas, but mercury oxychloride is formed. P. Grouvelle reported previously that when chlorine acts on mercuric oxide suspended in water, mercury oxychloride, very slightly soluble in cold water, is formed. L. J. Thenard found that the liquid contained both chloride and chlorate of mercury, also in soln. A. J. Balard, however, believed that these bodies are formed consecutively, and that their existence was preceded by that of a mercuric hypochlorite, as takes place with the salts of silver, and, as previously indicated, he prepared hypochlorous acid by the action of chlorine on mercuric oxide suspended in water. No mercury hypobromite has yet been isolated. There is a possible formation of mercury hypoiodite, or more probably of hypoiodous acid, when iodine is shaken up with... 

Electrolytic Processes for the Preparation of Hypochlorites, Hypobromites, and Hypoiodites... 

Prepared by reaction (I) of iodine and mercuric oxide (see also Mercury) suspension in water, mercuric iodide being simultaneously formed. (2) of sodium hypoiodite and an acid, excess acid yielding iodine. 

Oxidation of aldoses by hypoiodite can also be used for preparative purposes.7 Other types of halogen oxidants, especially A-halo compounds, are useful. For example, A -bromocarbamide was recommended by Kiss8 as a selective and convenient reagent for oxidizing benzylated sugars to their corresponding aldonolactones in yields exceeding 90%. Another example is the use of A-iodosuccinimide and tetrabutylammonium iodide.9... 

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