Lead IV salt

Plumbi-. plumbic, plumbi-, lead(lV). -oxyd, n. plumbic oxide, lead dioxide, lead(IV) oxide, -salz, n. plumbic salt, lead(IV) salt, -verbindimg, /. plumbic compoimd, lead(IV) compound. 

Electrochemical oxidations at an electron-deficient platinum electrode have considerable resemblance to oxidations by lead(IV) salts or halogens in methanol but none whatever to oxidations by palladium(II) salts. At temperatures between 90 and 130°C in solution these smoothly convert... 

Reisinger et al. [21] used the gas chromatographic-atomic absorption spectrometric technique to demonstrate that biomethylation of inorganic lead does not account for the presence of organolead compounds in sediments. Sulphide induced chemical conversion of organic lead(IV) salts into alkyl lead compounds is, however, possible. 

Halogenomethylpyrroles have been oxidized with lead(IV) salts or by chromium trioxide to yield the formylpyrroles, whilst catalytic hydrogenolysis or zinc-acetic acid reduction produces the 2-methylpyrroles (B-77MI30504). The methyl derivatives are also obtained by hydride reduction of trifluoromethyl-pyrroles and -indoles, and trifluoromethylindoles are converted into the carboxylic esters by ethanol under basic conditions (74JOC1836). 

In contrast with the indoles, C-aminopyrroles are less susceptible to autoxidation. Aerial oxidation produces iminopyrroles, which subsequently polymerize or give rise to imidopor-phins. The iminopyrroles are also formed as a result of the oxidation of the aminopyrroles with lead(IV) salts, whilst controlled oxidation with iron(III) and chromium(Vl) salts gives pyrrolylhydroxylamines and the azoxy derivatives, respectively (B-77MI30507). 

Lead(IV) salts will a-oxygenate enol ethers as they do enols vide supra), although in this case the process involves bisoxygenation of the unsaturated Ullage and subsequent hydrolysis. For example, the combination of lead tetrabenzoate and triethylammonium fluoride at 0-25 C effects efficient a-benzoyl-oxylation, e.g. (68) to (69). 0, y-Unsaturated ketones are also successfully oxidized, e.g. (70) to (71). The correspon ng LTA a-acetoxylations are possible, but the benzoate salt remains the transition metal reagent of choice for these substrates.These reactions appear to be uniformly efficient and perluq)S deserve wider synthetic tq>plication. 

Partial syntheses of oxindoles and pseudoindoxyls were already known at the time of publication of Volume VIII. Exposure of yohimbines or heteroyohimbines to Z-butyl hypochlorite (46) or lead-IV salts of strong carboxylic acids (4) afforded the corresponding indolenines (Cl, X = Cl or RCO2 ), which upon acid treatment rearranged to oxindoles, whereas base treatment led to pseudoindoxyls. The method has been used in the partial syntheses of mitraphylline and isomitraphylline (46). 

Acetic acid, lead(IV) salt [Lead tetracetate], 55,44, 115... 

Lead(IV) salts/iodine Carboxylic acid esters from 2 carboxylic acid molecules... 

Both Sn and Pb can also react to form tin(IV) and lead(IV) salts, respectively. 

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