Mercury II salts

Mercuration. Mercury(II) salts react with alkyl-, alkenyl-, and arylboranes to yield organomercurials, which are usehil synthetic intermediates (263). For example, dialkyhnercury and alkyhnercury acetates can be prepared from primary trialkylboranes by treatment with mercury(II) chloride in the presence of sodium hydroxide or with mercury(II) acetate in tetrahydrofuran (3,264). Mercuration of 3 -alkylboranes is sluggish and requires prolonged heating. Alkenyl groups are transferred from boron to mercury with retention of configuration (243,265). 

F E R R I E R Chiral cyclohexanone synthesis Transtormatlon o< unsaturated glycosides into cyclohexanone derivatives by heating in aqueous acetone with mercury (II) salts... 

The use of the other mercury(II) salts (acetate and bromide) in this cyclization led to a mixture of anomenc 2 deoxyhexopyranosides with low yields [54]... 

Interaction of iron(II) chloride with the lithium salt of R4B2NJ (R = Me, Et) gives sandwiches 61 (R = Me, Et) (67ZAAC1, 96MI4), resembling in electronic properties those of ferrocene (99ICA(288)17). The n- rf-) complex stems from the further complex-formation of 61 (R = Me, Et) with mercury(II) salts via the unsubstituted nitrogen atom. 

Merkuri-jodid, n. mer curic iodide, mercury (II) iodide, -nitrat, n. mercuric nitrate, mercury-(II) nitrate. -oxyd, n. mercuric oxide, mercury (II) oxide, -rhodanid, n. mercuric thiocyanate, mercury(II) thiocyanate, -salz, n. mercuric salt, mercury (II) salt, -sulfati n. mercuric sulfate, mercury (II) sulfate, -sulfidt ti. mercuric sulfide, mercury (II) sulfide. -sulfozyamd, n. mercuric thiocyanate. 

To determine the purity of a sample of a mercury(II) salt, the following procedure in which the compound is reduced with phosphorous (phosphonic) acid may be used to assay a sample of a mercury(I) salt, the reduction with phosphorous acid is omitted. 

A. Mercury(II) chloranilate method Discussion. The mercury(II) salt of chloranilic acid (2,5-dichloro-3,6-dihydroxy-p-benzoquinone) may be used for the determination of small amounts of chloride ion. The reaction is ... 

Monoalkylthallium(III) compounds can be prepared easily and rapidly by treatment of olefins with thallium(III) salts, i.e., oxythallation (66). In marked contrast to the analogous oxymercuration reaction (66), however, where treatment of olefins with mercury(II) salts results in formation of stable organomercurials, the monoalkylthallium(III) derivatives obtained from oxythallation are in the vast majority of cases spontaneously unstable, and cannot be isolated under the reaction conditions employed. Oxythallation adducts have been isolated on a number of occasions (61, 71,104,128), but the predominant reaction pathway which has been observed in oxythallation reactions is initial formation of an alkylthallium(III) derivative and subsequent rapid decomposition of this intermediate to give products derived by oxidation of the organic substrate and simultaneous reduction of the thallium from thallium(III) to thallium(I). The ease and rapidity with which these reactions occur have stimulated interest not only in the preparation and properties of monoalkylthallium(III) derivatives, but in the mechanism and stereochemistry of oxythallation, and in the development of specific synthetic organic transformations based on oxidation of unsaturated systems by thallium(III) salts. 

The reactions of acetylenes with thallium(III) salts are of considerable interest in that the results can be used in a qualitative comparison of reactivity between thallium(III) and mercury(II). Mercury(II) salt-catalyzed hydration of the C=C bond is a much studied and synthetically very useful process, although the detailed mechanism of the reaction is not known. The only published data available on the reactions of acetylenes with thallium-(III) salts are due to Uemura et al. 161), who employed thallium(III)... 

Littler has studied the oxidation of cyclohexanone with lead(IV), thallium(III), and mercury(II) salts (84), and found that, with all three reagents the rates of oxidation are independent of the concentration of oxidant. Oxidation by thallium(III) and mercury(II) in 35% aqueous perchloric acid showed first-order dependence on [H" ], and Littler suggested that the results were best interpreted in terms of the reaction sequence shown in Scheme 27. The major product of thallium(III) oxidation of... 

Mercaptoethanol reagent 380 Mercury cations 144,311 Mercury lamps 20, 22 ff emission lines 23, 24 -, high pressure 22 ff -, technical data 23 Mercury(I) nitrate reagent 337 Mercury(II) salt reagent 340 Mesaconic acid 61 Mesoporphyrin 101, 102 Metal cations 310—312,398 Metal complexes 248, 398 Methanol, dipole moment 97 Methine dyestuffs 360 4-Methoxyaniline see Anisidine 4-Methoxybenzaldehyde see Anisaldehyde Methoxybenzaldehyde derivatives 72 Methoxycinnamic acid 277... 

It is dangerous to put mercury (II) salts in contact with acetylene in the presence of concentrated sulphuric acid. 

The reactions of mercury(II) salts with oligo-amines afford informative examples for the fact that counterions induce the formation of a distinct complex or select a distinct complex in an equilibrium to crystallize with. Thus, Hg11 acetate with dien under exactly the same reaction conditions, in the presence of C104- or PF6-, yields the dinuclear complex [Hg2(dien)3](C104)4 or the mononuclear species [Hg(dien)(H20)](PF6)2, respectively, both characterized by IR, H, and 13C NMR spectrometries, by fast-atom bombardment (FAB) MS, cyclovoltammetry, and X-ray structure analyses.209 In the first compound Pna2, Z = 4), one Hg adopts five-coordination with one tridentate and one bidentate dien ligand, which with the remaining N-donor binds to the... 

In a process known as peroxymercuration, hydrogen peroxide and alkyl hydroperoxides can be alkylated by alkenes in the presence of a suitable mercury(II) salt... 

Mercury(II) salts, Nitric acid, (Sulfuric acid)... 

See Dinitrogen oxide or Halogens, both above Oxygen, below Calcium hypochlorite Acetylene Nitric acid Acetylene, Mercury(II) salts Nitrogen oxide Dienes, Oxygen Ozone Acetylene... 

It explodes without melting when heated [1]. The title compound and its barium, lead(II), and mercury(II) salts were studied by DTA and DSC techniques. The lead salt is the least stable and most powerful primary explosive of the 4 compounds [2],... 

In a,jS-unsaturated stannyl esters the acyl moiety is displaced by mercury(II) salts without affecting carbon-carbon double bonds, as shown in reaction 71322. 

Electrophilic substitution at the anthraquinone ring system is difficult due to deactivation (electron withdrawal) by the carbonyl groups. Although the 1-position in anthraquinone is rather more susceptible to electrophilic attack than is the 2-position, as indicated by jt-electron localisation energies [4], direct sulphonation with oleum produces the 2-sulphonic acid (6.3). The severity of the reaction conditions ensures that the thermodynamically favoured 2-isomer, which is not subject to steric hindrance from an adjacent carbonyl group, is formed. However, the more synthetically useful 1-isomer (6.7) can be obtained by sulphonation of anthraquinone in the presence of a mercury(II) salt (Scheme 6.4). It appears that mercuration first takes place at the 1-position followed by displacement. Some disulphonation occurs, leading to the formation of the 2,6- and 2,7- or the 1,5- and 1,8-disulphonic acids, respectively. Separation of the various compounds can be achieved without too much difficulty. Sulphonation of anthraquinone derivatives is also of some importance. 

Thioglycosides were the first example of an anomeric derivatization that serves the dual role of protection and activation. They were introduced in glycosylation reactions by Ferrier et al. in 1973, who used mercury(II) salts as activator.1 After the development of improved methods of their synthesis and activation, thioglycosides together with trichloroacetimidates are now the most commonly used glycosyl... 

Addition of electrophilic mercury(II) salts to carbon-carbon double bonds in nucleophilic solvents (i.e. oxymercuration, solvomercuration etc.) is a well documented methodology in organic synthesis146. In these reactions a mercuric salt, usually the chloride or... 

The ratio of the two products is primarily affected by the nature of the mercury(II) salt and also by the reaction conditions. Since the formation of these compounds could result from either a kinetically or a thermodynamically controlled mercuration process, a study of the mercuration of 3 in the presence of aromatic amines using various mer-cury(II) salts has been more recently carried out in order to determine the conditions under which aminomercuration is reversible, and the results have been compared to those of the oxymercuration170. 

It has therefore been established170 from the product distributions that, while the oxymercuration is reversible, unless a base (e.g. sodium acetate) is added to the reaction medium, and gives almost exclusively the more stable compound 199, the aminomercu-ration takes place to give the kinetically controlled adduct 200, or under thermodynamic control the aminomercurial 201. Reactions are kinetically controlled when the mercurating species is a mercury(II) salt deriving from a weak acid such as mercury(II) acetate. Conversely, they are thermodynamically controlled with the covalent mercury(II) chloride. In the latter case, the presence of a strong acid in the medium allows the thermodynamically controlled product to be obtained. 

Considering the monoaminomercuration-demercuration of 1,4-hexadiene with /V-me-thylaniline leads to V-methyl-lV-(l-methylpent-3-enyl)aniline, the stereoselective synthesis of /V-alkoxycarbonyl or /V-tosyl s-2,5-dimethylpyrrolidine from the same diene has been explained172 on the basis of an initial amidomercuration reaction on the terminal bond followed by the second addition of mercury(II) salt to the internal double bond, on the less sterically hindered site (equation 171). 

There are several useful means for preparation of organomercury compounds. The general metal-metal exchange reaction between mercury(II) salts and organolithium or magnesium compounds is applicable. The oxymercuration reaction discussed in Section... 

Mercury metal forms both mercury(I) and mercury(II) salts. Oxidizing acids in excess amounts and under hot conditions yields mercury(ll) salts. Thus, heating mercury with concentrated nitric or sulfuric acid yields mer-cury(ll) nitrate or mercury(ll) sulfate ... 

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