Dialkyl lead 4

In water, tetraalkyl lead compounds are subject to photolysis and volatilization with the more volatile compounds being lost by evaporation. Degradation proceeds from trialkyl lead to dialkyl lead to inorganic lead. Tetraethyl lead is susceptible to photolytic decomposition in water. Triethyl and trimethyl lead are more water-soluble and therefore more persistent in the aquatic environment than tetraethyl or tetramethyl lead. The degradation of trialkyl lead compounds yields small amounts of dialkyl lead compounds. Removal of tetraalkyl lead compounds from seawater occurs at rates that provide half-lives measurable in days (DeJonghe and Adams 1986). 

Disilylation of furo[3,4-r-]pyridine followed by dialkylation leads to the formation of a-disubstituted derivatives in good yields (61-70%). This methodology provides a key step in the synthesis of the pyridone alkaloid cerpegin, 54 <2004OL2925>. 

Waste waters containing low concentrations of soluble organic lead in the presence of high concentrations of other diverse ions such as Cl pose a particularly difficult treatment problem. Generally, organic lead exists in solution as the tri- or dialkyl lead chloride species. These salts are not amenable to the conventional methods used to remove inorganic lead, viz., those of pH adjustment followed by settling. The technique of chemical conversion of the... 

Any dialkyl lead present was determined spectrophotometrically as the dialkyllead 4(2-pyridylazo)resorcinol (P.A.R.) complex at pH 9. Trialkyl lead does not form a complex with P.A.R. therefore its concentration was obtained by conversion to the dialkyl lead form in iodine monochloride solution followed by determination as the P.A.R. complex. Any inorganic lead in solution was... 

At-Alkylation of 1-hydroxyimidazoles 249 produces 3-substituted imidazole 1-oxides 228 (R=Aik) in low yields due to competing O-alkylation and dialkylation leading to 1-alkoxyimidazoles 250 and l-alkyl-3-alkyloxy-imidazolium salts 251, respectively (1970ZC211,1990S795) (Scheme 70). 

Polyesters obtained by interfacial polycondensation of aliphatic and aromatic diacids with dialkyl lead dichloride or dialkyl stannum dichloride possess biocide properties [105]. Ferrocene moieties may be also incorporated. 

Finally, the reaction of 374 with cyclic unsaturated substrates such as 1,3-cyclohexadiene, 1,4-dihydronaphthalene 1,4-dioxide, or acenaphthalene resulted in formation of cycloadducts 405, 407, and 409, respectively. These compounds could be subsequently aromatized by the use of DDQ in the case of 405 and 409 or polyphosphoric acid (PPA) in the case of 407 to generate l,3-dithiole-2-thiones 406, 408, and 410 (Scheme 55) <1996TL8085, 1999TL801>. The compound 410 was further treated with potassium /< r7-butoxide to give the dithiolate intermediate 411, which underwent dialkylation leading to 412 (Scheme 56) <1999J(P2)755, 1999TL801>. 

Dialkyl-lead salts and trialkyl-lead salts in aqueous solution react with dithizone forming chloroform-soluble red complexes as do Pb+ ions (see page 000). If Pb+2 ions are present, they are complexed with EDTA to prevent interference. ... 

Procedure. A drop of a saturated aqueous solution of EDTA is added to a drop of the test solution in a micro test tube and the mixture shaken with a few drops of a solution of dithizone in chloroform or carbon tetrachloride (see page 000). The green color of the reagent solution becomes yellow-orange when dialkyl-lead salts are present. Trialkyl-lead salts form a red-orange complex with dithizone. 

Trialkyl-lead hydrides and dialkyl-lead dihydrides were made by reducing the corresponding chlorides with lithium aluminium hydride at low temperature (- 78°)36p 37.38,... 

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