Mercury alkyl derivatives

Arylmercuric halides may be used in place of diarylmercurials. Excellent yields, often 90-98%, were obtained in many cases. Table III lists some examples. Oxidative degradation studies of selected products showed that the aryl carbon atom originally attached to mercury was the one that became bonded to the apical carbon atom of the cluster. This reaction was much less useful in the preparation of alkyl derivatives, because of very long reaction times (1-2 weeks) giving at best moderate yields (Table III). The reaction of a-haloalkylmercurials with HCCo3(CO)9 occurred... 

Alkyl derivatives of mercury in the oxidation state +2 are produced during the solvomer-curation of olefins (the first partial reaction of the reaction sequence in Figure 1.11). 

In its covalent compounds thallium shows no reluctance to utilizing the two 6s electrons for bond formation. Indeed monoalkyl derivatives Tl(Alk) in which the valence group would be (2, 2) are not known, whereas trialkyls (valence group 6) are known and the most stable alkyl derivatives are the dialkyl halides such as [T1(CH3)2]I. These are ionic compounds-[T1(CH3)2] OH being a strong base—and in the Tl(Alk)2 ions the thallium atom has the same outer electronic structure as mercury in CH3-Hg-CH3, viz. (4). Accordingly the (CH3-T1-CH3) ion is linear, as shown by the determination of the crystal structure of Tl(CH3)2l. In molecules such as Tl(Alk)2A, where A represents a molecule of a /3-diketone, T1 apparently has the valence group (8). 

Alkylation of 2-substituted quinazolin-4(3//)-ones by reaction with sodium hydride in dimethylformamide followed by alkylation provided O-and N-alkyl derivatives. The extent of alkylation at the different sites was reasonably explained in terms of steric properties of the 2-substituents. The silver salt of quinazolin-4(3H)-one and tetra-0-acetyl-) -D-glucopyrano-syl bromide gave a 40% yield of the 0-glycosyl derivative in contrast with the mercury salt, which gave mainly the iV-3-glycosyl derivative. As in the alkylation of mercapto compounds, quinazoline-4(3H)-thione gave the S-glycosyl derivative. If sodium hydroxide was used as base a 56% yield of the... 

High sensitivity of alkylmercurial compounds to electron-capture detection has prompted conversion of inorganic mercury into its thermally stable alkyl derivatives for gas chromatographic analysis. Among the more commonly used alkylating reagents are sodium tetraphenylborate, tetramethyltin and the arylsulphinates. 

Phosphonate analogues of Reissert compounds (76) have been prepared and converted into 1-alkyl-isoquinolines (Scheme 49). Treatment of a number of A -methylisocarbostyrils with mercuric acetate gave rise to 4-mercuri-ated derivatives, which underwent insertion reactions with methyl acrylate and with styrenes in the presence of palladium chloride (Heck reaction). 

Colourless alkyl derivatives of Na and K are obtained by transmetallation reactions starting from mercury dialkyls (equation 18.4). 

A different method of preparation is advisable if the pure, solvent-free organolithium compound is required. In a procedure due to Schlenk and Holtz50 the organolithium compound is prepared from metallic lithium and the organomercury compound in an indifferent solvent since most organolithium compounds, in particular the higher alkyl derivatives, are very readily soluble in hydrocarbons, they can be easily separated from the separating mercury and then obtained pure by evaporation of the solution. 

In CdMea, ( Cd H) is positive, but /( Cd H) has the opposite sign. Although /( Hg H) is negative in alkyl derivatives of mercury it is positive in vinyl derivatives. Couplings to in Hg-CFs compounds have the opposite sign to those to in the analogous Hg-Me system. 

The alkyl derivatives R3M (M = P, As, Sb, Bi) are all extremely susceptible to oxidation. MOjP inflames in the air and even under more controlled conditions gives a complex mixture of products with oxygen via radical chain reactions. The triaryls, however, are air stable. Careful oxidation with aqueous hydrogen peroxide or a suspension of mercury(II) oxide afibrds the oxides R3MO (not M = Bi). 

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