Lead diacetate

The disappearance of fche iodine color is not indicative of the end of the reaction, sinc lead tetraacetate itself reacts with iodine under the reaction con-ditions giving lead diacetate, carbon dioxide, and methyl iodide. The reaction should be interrupted after 90 minutes even if a faint iodine color persists. 

The in situ preparation of the active fluorinating species lead diacctate difluoride from lead(I V) acetate (dissolved in chloroform) and hydrogen fluoride at 0 C was described in an earlier report.48 The crystalline lead diacetate difluoride could be isolated by a modified preparation.49... 

In 1931, Dimroth and Bockemtiller claimed that a new fluorinating agent, lead(IV) fluoride, was obtained in situ from lead(IV) acetate and anhydrous hydrogen fluoride in chloroform at 0 C.19 Later it was shown that this agent is lead diacetate difluoride, which can be isolated in the pure state.20... 

It has been shown that 1,1-diphenylethene does not react with preformed lead(IV) fluoride, prepared by the reaction of lead(II) fluoride and elemental fluorine,20 whereas treatment with lead diacetate difluoride19,20 converts 1,1-diphenylethene into l,l-difluoro-l,2-diphenylethane (2), due to a radical rearrangement. Dimer 3 is also isolated.21... 

The oxidation step has been represented10 32 as a transfer of an electron pair from oxygen to PbIV, with formation of lead diacetate and acetoxy anion, as follows. 

The Pb analogues of germocanes and stannocanes are almost unknown. The rare examples known include 4,6-dithiaplumbocanes Ph2Pb(SCH2CH2)2D 412 (D = O) and 413 (D = S), which were prepared from lead diacetate and the corresponding disodium... 

Pyridine is an important cofactor in the reaction system that leads to cleaner reactions and better yields of products than in its absence.15 It can act either as a u-donor for Pb(rv) or as a base catalyzing the keto-enol tautomerism. The u-donor effect was evidenced spectroscopically by the formation of adducts of pyridine with lead tetraacetate.45,4511 Moreover, pyridine catalyzed the ligand redistribution of twcfc-methoxyphenyllead triacetate to bis( r/ -mcthoxy-phenyl)lead diacetate. Other u-donor catalysts can be used and their nature is highly important for the success of the reaction. NaOMe and HOBT showed a modest effect, but a thousand-fold increase in rate over the uncatalyzed reaction was observed when 1,10-phenanthroline was employed and near quantitative yields of arylation products were obtained (Equation (16)).44... 

Thus, in the reaction of aryllead triacetate with phenols, an initial ligand exchange affords an aryl-(aryloxy)lead diacetate intermediate which can have the aryloxy ligand either in the axial position 51 or in the equatorial position 52 (Scheme 9). If the aryloxy group is in the axial position, pseudorotation can easily interconvert this conformer with... 

Symmetrical divinyllead diacetates can be obtained directly from the corresponding vinylboronic compound through reaction with lead tetraacetate in chloroform at room temperature. Thus, the reaction of (E)-styrylboronic acid 59 with lead tetraacetate in chloroform afforded the bis-(/. )-styryllead diacetate 60 and the reaction of ( )-hex-l-enylboronic acid 61 led to the relatively unstable bis-[fE)-hex-l-enyl]lead diacetate 62 (Equations (54) and (55)). 

Elbs,7 by the electrolysis of lead diacetate in glacial-acetic-acid solution, obtained at the anode crystallized lead tetracetate ... 

SYNS ACETIC ACID, LEAD (2+) SALT TRIHYDRATE BIS(ACETATO)TRIHYDROXYTRILRAD BLEIAZETAT (GERMAN) LEAD ACETATE TRIHYDRATE LEAD DIACETATE TRIHYDRATE PLUMBOUS ACETATE... 

To a solution of 3-amino-2-cthyl-4(3//)-quinazolinone in dry CH2C12 (1 mL/100 mg of amine) at — 20 C is added 1.05 mol equiv of Pb(OAc)4. 3 Mol equiv of the alkene are added and the solution allowed to warm to 20LC. The insoluble lead diacetate is separated and washed with CH2C12. The combined CH,C12 solution is washed successively with aq NaHCO, and H20, then dried, and the solvent is removed under reduced pressure. 

Alkenyl, Alkynyl, Aryl and Heteroaryl Acids. Treatment of readily accessible (E)- and (Z)-alkyl and aryl substituted vinyl boronates (196) with triethyl phosphite in the presence of lead diacetate results in their stereospecific transformation into (E)- and (Z)-vinylphosphonates (197) (Scheme 53). ° Palladium acetate catalysed Mizoroki-Heck reaction of arylboronic acids (198) with diethyl vinylphosphonates (199) is an effective synthetic approach to... 

Diaryl tellurium compounds are cleanly oxidized at 20° to diaryl tellurium diacetates by lead tetraacetate in benzene or toluene. The isolation of the diaryl tellurium diacetates, which are soluble in aromatic hydrocarbons, is facilitated by the precipitation of lead diacetate . 

In agreement with the hypothesis that similar intermediates are involved in p-dicarbonyl ar in which the steric decompression resulting from the ligand coupling step favours the arylatioi more substituted p-dicarbonyl substrates, the thermal instability of the (p-methoxyphenyl)ph lead diacetates increased in the series ... 

AMMONIUM DIHYDROGEN PHOSPHATE (7783-28-0) Contact with air slowly forms anhydrous ammonia. Contact with caustics forms anhydrous ammonia gas. Violent reaction with strong oxidizers, potassium chlorate, strong bases. Reacts with antimony(V) pentafluoride, lead diacetate, magnesimn, silver nitrate, zinc acetate. AMMONIUM DISULFATO-NICKELATE (II) (15699-18-0) NiS04(NH4)2S04 jHj0 A weak oxidizer. Aqueous solution is acidic. Reacts violently with carbon dust, potassium, finely divided... 

ARAGONITE (1317-65-3) CaCO, Noncombustible solid. Incompatible with acids (exothermic reaction with extensive foaming and release of gas is caused when acid is highly concentrated) acid salts alum, ammonium salts fluorine (ignition), germanium, lead diacetate, magnesium, mercurous chloride, silicon, silver nitrate, titanium. Thermal decomposition above 1517°F/825°C releases calcium oxide (quicklime) and COj. 

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