Mercuric oxide, use in oxidation

Mercuric oxide, use in oxidation of hydrazones, 50, 28 with 3-chlorocyclobutanecar-boxylic acid and bromine to give l-bromo-3-chlorocyclo-butane, 51, 106 MERCURIC OXIDE-MODIFIED HUNS-DIECKER REACTION 1-BRQMO-... 

Strike got the journal article for this recipe as literature citation used in the original Wacker oxidation Strike used for Method 2. In it both mercuric acetate, and to an extent, lead acetate produced ketones as described. Someone-Who-ls-Not-Strike also got a certain ketone. But maybe they were lucky or just plain wrong. Most people on Strike s site say this mercuric acetate thing... 

Batteries. Many batteries intended for household use contain mercury or mercury compounds. In the form of red mercuric oxide [21908-53-2] mercury is the cathode material in the mercury—cadmium, mercury—indium—bismuth, and mercury—zinc batteries. In all other mercury batteries, the mercury is amalgamated with the zinc [7440-66-6] anode to deter corrosion and inhibit hydrogen build-up that can cause cell mpture and fire. Discarded batteries represent a primary source of mercury for release into the environment. This industry has been under intense pressure to reduce the amounts of mercury in batteries. Although battery sales have increased greatly, the battery industry has aimounced that reduction in mercury content of batteries has been made and further reductions are expected (3). In fact, by 1992, the battery industry had lowered the mercury content of batteries to 0.025 wt % (3). Use of mercury in film pack batteries for instant cameras was reportedly discontinued in 1988 (3). 

Pharmaceuticals. A variety of mercury compounds have had pharmaceutical appHcations over the years, eg, mercury-containing diuretics and antiseptics. Whereas some mercury compounds remain available for use as antiseptics such as merbromin [129-16-8] mercuric oxide, and ammoniated mercury [10124-48-8] or as preservatives such as thimerosal [54-64-8] in dmgs and cosmetics, most have been supplanted by more effective substances. A detailed discussion of mercury-containing antiseptics is available (37). Many hospitals use mercury metal to serve as weight for keeping nasogastric tubes in place within the stomach. 

Mercuric Cyanides. Mercuric cyanide7, Hg(CN)2, is a white tetragonal crystalline compound, Httle used except to a small degree as an antiseptic. It is prepared by reaction of an aqueous slurry of yellow mercuric oxide (the red is less reactive) with excess hydrogen cyanide. The mixture is heated to 95°C, filtered, crystallized, isolated, and dried. Its solubihty in water is 10% at 25°C. 

Mercuric chloride is widely used for the preparation of red and yellow mercuric oxide, ammoniated mercury/7(9/USP, mercuric iodide, and as an intermediate in organic synthesis. It has been used as a component of agricultural fungicides. It is used in conjunction with sodium chloride in photography (qv) and in batteries (qv), and has some medicinal uses as an antiseptic. 

Yellow mercuric oxide may be obtained by precipitation from solutions of practically any water-soluble mercuric salt through the addition of alkah. The most economical are mercuric chloride or nitrate. Although yellow HgO has some medicinal value in ointments and other such preparations, the primary use is as a raw material for other mercury compounds, eg, Millon s ha.se[12529-66-7], Hg2NOH, which is formed by the reaction of aqueous ammonia and yellow mercuric oxide. 

Galen, a physician whose views outUved him by about a thousand years, died about 200 AD. He beUeved that mercurials were toxic, and did not use any mercury compound therapeutically. However, as a result of Arabian influence, the therapeutic uses of mercury were slowly recognized by Western Europe. In the thirteenth century mercury ointments were prescribed for treating chronic diseases of the skin. Mercury and its compounds, such as mercurous chloride, mercuric oxide, mercuric chloride, and mercuric sulfide, were used widely from the fifteenth to the nineteenth centuries, and to some extent in the twentieth century. During the first half of the twentieth century, the primary therapeutic uses of mercury included bactericidal preparations, such as mercuric chloride, mercuric oxycyanide, and mercuric oxide and diuretics, such as aryl HgX (Novasural) and mercurated ahyl derivatives (14). 

Although the 2inc—mercuric oxide battery has many excellent qualities, increasing environmental concerns has led to a de-emphasis in the use of this... 

The formation of an enamine from an a,a-disubstituted cyclopentanone and its reaction with methyl acrylate was used in a synthesis of clovene (JOS). In a synthetic route to aspidospermine, a cyclic enamine reacted with methyl acrylate to form an imonium salt, which regenerated a new cyclic enamine and allowed a subsequent internal enamine acylation reaction (309,310). The required cyclic enamine could not be obtained in this instance by base isomerization of the allylic amine precursor, but was obtained by mercuric acetate oxidation of its reduction product. Condensation of a dihydronaphthalene carboxylic ester with an enamine has also been reported (311). 

In a modified procedure the free carboxylic acid is treated with a mixture of mercuric oxide and bromine in carbon tetrachloride the otherwise necessary purification of the silver salt is thereby avoided. This procedure has been used in the first synthesis of [1.1.1 ]propellane 10. Bicyclo[l.l.l]pentane-l,3-dicarboxylic acid 8 has been converted to the dibromide 9 by the modified Hunsdiecker reaction. Treatment of 9 with t-butyllithium then resulted in a debromination and formation of the central carbon-carbon bond thus generating the propellane 10." ... 

The more generally known mercuric oxide-mercuric chloride hydrolysis 2 may also be used, and in the present case it gives a yield of about 90%. The reductive desulfurization of Part E is also based on the work of Mukaiyama.12 It is clearly superior to Raney nickel desulfurization, which gives only 36-45% of 3-benzylindole. 

In explosives, calcium oxide has been used for many years according to Daniel (Ref 1) in devices such as the Igniter of Jarotimek. This is a device used in blasting operations, and consists of a double cartridge containing compressed CaO in one end and a flammable mixt (usually a mixt of 50% KC103 and 50% mercuric fulminate) in the other end. The flammable end is... 

Vanadium pentoxide and mercuric oxide were used as catalysts for the hydrogen peroxide oxidation of bis(phenylthio)methane to its monooxide 17a31 (equation 5). From the synthetic point of view, it is interesting to note that vanadium pentoxide, in addition to its catalytic action, functions also as an indicator in this reaction. In the presence of hydrogen peroxide, the reaction mixture is orange while in the absence of hydrogen peroxide a pale yellow colour is observed. Thus, it is possible to perform the oxidation process as a titration ensuring that an excess of oxidant is never present. 

Among phosphonate esters (170) used in olefin synthesis were those with R = S-CeHi-Br-/ , S02 C6H4-Br-A CO-NHR, and S CHa CEi-XHa. The allyl vinyl thio-ethers (171) obtained using the last of these gave a-allyl-aldehydes on pyrolysis in the presence of red mercuric oxide. 

Similar designs are used for other REs on the basis of poorly soluble mercury compounds (1) the mercury-mercurous sulfate RE with H2SO4 or K2SO4 solutions saturated with Hg2S04, for which = 0.6151V and (2) the mercury-mercuric oxide RE, for measuring electrode potentials in alkaline solutions, with KOH solution saturated with HgO, for which = 0.098 V and E = 0.920 V. 

In selecting reference electrodes for practical use, one should apply two criteria that of reducing the diffusion potentials and that of a lack of interference of RE components with the system being studied. Thus, mercury-containing REs (calomel or mercury-mercuric oxide) are inappropriate for measurements in conjunction with platinum electrodes, since the mercury ions readily poison platinum surfaces. Calomel REs are also inappropriate for systems sensitive to chloride ions. 

Chemical precipitations which are not dependent on pH are used in various processes. Sometimes the reagent is reasonably set for a certain metal and this is the situation in the precipitation of silver as silver chloride. The only other insoluble common metal chlorides of significance are lead chloride, cuprous chloride, and mercurous chloride. This implies that precipitation of cuprous and mercurous chlorides generally may be avoided by ensuring that the metals occur in their higher oxidation states, cupric and mercuric states. The separation of silver in its chloride form is rarely employed for bulk precipitation, but is quite useful for removing relatively small amounts of the metal when it occurs in minor amounts. 

The earliest oxidations were effected with nitrous fumes and later with mercuric oxide and isoamyl nitrite.74 Lead tetraacetate in acetic acid is in many cases the reagent of choice, but the removal of by-products can present some difficulties.75 IV-Haloimides and amides in alcoholic solutions have been reported to yield essentially pure tetrazolium salts76 and have been found specially useful in the preparation of heteroaryl-substituted tetrazolium salt.77,78 The novel formazans 49 have been successfully oxidized to 50 using 7V-chloro succinimide (Eq. II).79 tert-Butyl hypo-... 

Advantage has been taken of the aforementioned observations in the synthesis of a terthiophene natural product, arctic acid (147) [123]. Pd-catalyzed carbonylation of bromobisthiophene 25, obtained from the Kumada coupling of 2-thienylmagnesium bromide and 2,5-dibromothiophene, gave bithiophene ester 144, which was converted to iodide 145 by reaction with iodine and yellow mercuric oxide. Subsequent propynylation of 145 was then realized using the Sonogashira reaction with prop-l-yne to give bisthienyl alkyne 146, which was subsequently hydrolyzed to 5 -(l-propynyl)-2,2 -bithienyl-5-carboxylic acid (147), a natural product isolated from the root of Arctium lappa. 

Thioetherification of PECH is feasibly performed in DA-solvents as already described in the patent (20J. For example, the highest substitution was obtained by the reaction of P(ECH-EO)(1 1 copolymer of epichloro-hydrin and ethylene oxide) and equimolar thiophenoxide in HMPA at 100°C for 10 h as DS 83% for sodium and 93% for potassium salts. The DS in our nucleophilic substitution was estimated by the elemental analysis as well as the titration of liberated chloride ion with mercuric nitrate (21). In the latter method, reacted medium was pretreated with hydrogen peroxide when the reductive nucleophiles which can react with mercuric ion were used. As described before for PVC, thiolation was also achieved conveniently with iso-thiuronium salt followed by alkaline hydrolysis without the direct use of ill-smelling thiolate. The thiolated PECH obtained are rubbery solids, soluble in toluene, methylene chloride, ethyl methyl ketone and DMF and insoluble in water, acetone, dioxane and methanol. 

By the early 1800s several chemists had separated potassium and sodium as elements from compounds. It was believed that metallic calcium could be obtained by similar methods. In 1808 Sir Humphry Davy finally produced the metallic element calcium from a mixture of lime and mercuric oxide by his experimental electrolysis apparatus. This was the same process he had previously used to discover several other alkali earth metals. 

Mercury oxide (HgO) exists in two forms, red and yellow mercuric oxides, and is related to mercurous oxide (Hg O), which is black. All have industrial uses, ranging from antiseptics to pigments. 

In an attempt to employ this route Curd, Rose et al. 58) treated p-chloro-phenylamidinothiourea with isopropylamine and mercuric oxide, but obtained mostly N-p-chlorophenyl-N -cyanoguanidine. Efforts to improve the results by numerous changes in conditions were unsuccessful in all cases biguanides were merely by-products, formed in yields less than 5%. A later patent 154) has however claimed the successful use of this route. 

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