Lead compounds reduction

Acetamido-4-methylselenazole can react with mercuric acetate to yield 5-mercuriacetate derivatives that can be converted to the chloro derivatives by the action of sodium chloride. Treatment with potassium iodide leads to reduction regenerating the initial compound with loss of mercury (Scheme 16) (4). 

Two classes of charged radicals derived from ketones have been well studied. Ketyls are radical anions formed by one-electron reduction of carbonyl compounds. The formation of the benzophenone radical anion by reduction with sodium metal is an example. This radical anion is deep blue in color and is veiy reactive toward both oxygen and protons. Many detailed studies on the structure and spectral properties of this and related radical anions have been carried out. A common chemical reaction of the ketyl radicals is coupling to form a diamagnetic dianion. This occurs reversibly for simple aromatic ketyls. The dimerization is promoted by protonation of one or both of the ketyls because the electrostatic repulsion is then removed. The coupling process leads to reductive dimerization of carbonyl compounds, a reaction that will be discussed in detail in Section 5.5.3 of Part B. 

The most important of the tertiary phosphine complexes of platinum(IV) are Pt(QR3)2X4, generally prepared by halogen oxidation [174] of cis- or trans-Pt(QR3)2X2 (Q = P, As, R = alkyl Q = Sb, R = Me), since direct reaction of the platinum(IV) halides with the ligands leads to reduction. Once made, the platinum(IV) compounds are stable to reduction ... 

TiCl4 also effectively promotes formation of imines and enamines from carbonyl compounds (Scheme 31). The combination of imine formation using TiCl4 and reduction leads to reductive alkylation of an amine moiety.113,114... 

In a recent study, the group of Moser has described the use of a polymer-bound borohydride in reductive aminations of tetrameric isoquinolines (Scheme 7.101) [122]. These tetrameric isoquinolines, which represented lead compounds in a search for antibacterial distamicyn A analogues, were prepared from the appropriate... 

In broad terms the coordination chemistries of technetium and rhenium are similar, and isomorph-ous compounds are frequently found. One important exception is the behavior with phosphanes. Since Tc is a stronger oxidant than Re, the reaction with phosphanes very often leads to reduction to Tc° and lower oxidation states. This is particularly the case with compounds derived from the... 

A still different scheme is used for the preparation of the benzimidazole buterizine (74). Alkylation of benzhydrylpiperazine with substituted benzyl chloride 70 gives the intermediate 7U Nucleophilic aromatic displacement on this compound by means of ethyl amine leads to reduction of the nitro group then gives the diamine T. Treatment of that with the orthoformate ester of pentanoic acid serves to form the imidazole ring. There is thus obtained the peripheral vasodilating agent buteri zi ne (74). ... 

The effectiveness of the BSWS as a volume reduction unit depends largely on the solubility of the lead compounds in the washing medium, the efficiency of density separation for removing discrete lead particles, and the particle size distribution in the feed soil. 

Electrochemical formation of Pb(II) complexes by anodic dissolution of lead [83-89] and studies on electrochemical properties of Pb(IV) complexes as well as organo-lead compounds have been reported [90, 91]. Electrogenerated chemiluminescence of Pb(II)-bromide complexes has been described [92]. Reduction of lead to Zintl ions, such as Pbg , has been... 

In some cases, the deposit of lead metal also consist of irregular aggregates far from the original particles of the lead compound [126], as can be seen in Fig. 2.10 for minium (Pb304)—another widely used pigment These features can be rationalized, assuming that the electrochemical pathway represented by Eq. 2.6 can eventually be coupled by a reductive process via formation of Pb + in solution... 

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