Oxidation of arylacetylhydrazones of carbonyl compounds with lead tetraacetate

Oxidation of the title compounds 8, 9 with lead tetraacetate at room temperature gives a variety of products depending on the substituents on the carbonyl carbon atom. Thus, on oxidation of the aldehyde derivatives 8 1,3,4-oxadiazolo derivatives 10 are obtained in good yields. However in some cases formation of N-acetyl-N-arylacetyl-N′-benzoylhydrazines 11 is also observed, whereas oxidation of the ketone hydrazones 9 gives in good yields the 2H,5H-1,3,4-oxadiazoles 15 or substituted monoacetoxy- 17 and diacetoxyalkanes 18 . The reaction mechanisms are also discussed.     

The oxidation of compounds capable of imine-enamine tautomerism with lead tetraacetate

Compounds capable of imine-enamine tautomerism react preferentially via their enamine tautomer giving a 2-acetoxyaldehyde which equilibrates with the starting imine. This derives from the extra nucleophilicity of the β-carbon of the enamine tautomer. The reaction of the imine isomer to form an aryl- or an alkylnitrenoid species is a minor pathway.     

Reactions of tin tetraacetate with benzothiazolines

Tin tetraacetate with 2,2-disubstituted benzothiazolines yields mono and disubstituted derivatives, the latter being the final product even with excess of the ligand. In the products the benzothiazoline ring of the ligands is absent, but a new azomethine group is found, thus characterising the products as tin(IV)Schiff2ba se complexes. The new compounds have been characterised by elemental analysis, IR, PMR, Molecular weight determination and a conductometric study.

---

Reaktionen von Zinntetraacetat mit Benzothiazolinen

Zusammenfassung Zinntetraacetat ergibt mit 2,2-disubstituierten Benzothiazolinen mono- und disubstituierte Verbindungen, wobei letztere auch mit Überschuß an Ligand die Endprodukte darstellen. In den Produkten fehlt der Benzothiazolinring, andererseits wird eine Azomethingruppe gefunden; damit sind die Produkte als Zinn(IV)-Schiff-Basen-Komplexe charakterisiert. Die neuen Verbindungen wurden mittels Elementaranalysen, IR,¹H-NMR, Molekulargewichtsbestimmungen und Leitfähigkeitsmessungen charakterisiert.

     

Mild chlorination of aromatic compounds with tin(IV) chloride and lead tetraacetate

SnCl₄/Pb(OAc)₄ acts as a safe source of Cl₂ for the chlorination of aromatic compounds. A variety of aromatic compounds are effectively chlorinated with SnCl₄/Pb(OAc)₄ under mild conditions. The mixture is a selective chlorinating agent, particularly with polyalkylbenzenes, polycyclic aromatic compounds and anisoles.     

The reaction of lead tetraacetate with hydrocarbons

The free radical reaction of lead tetraacetate with hydrocarbons has been investigated. The products of these reactions are the acetate esters. The hydrogen abstracting species from lead tetraacetate is found to have a primary to secondary to tertiary selectivity of 1:27:123 based upon relative reactivities.     

Oxidation of perfluoronaphthols by lead tetraacetate and lead dioxide

Depending on the reaction conditions, oxidation of perfluoronaphthols by Pb(OAc)₄ proceeds by two routes. Under mild conditions (20°C) oxidation leads to the products of dimerisation of perfluoronaphthoxy radicals. At a higher temperature (80°C) the reaction leads to acetoxydienones. The mechanistic aspects of oxidation of perfluoronaphthols by Pb(OAc)₄ are discussed.     

Solid-phase oxoalkylation of pyridines and quinolines with 1-methylcycloalkanols under the action of lead tetraacetate

A new procedure was developed for the introduction of the oxoalkyl fragment into N-heteroaromatic compounds of the pyridine and quinoline series. The procedure is based on the solid-phase reactions of lead tetraacetate with aromatic N-heterocycles and tertiary cycloalkanols.     

Solid-phase reactions of lead tetraacetate with tertiary cycloalkanols and pyridine

Russian Chemical Bulletin -     

Oxidative cyclization of some 1,3-dioximes with lead tetraacetate

Oxidation of 1,3-dioximes 1 with lead tetraacetate gives di-N-oxides of pyrazolines 4 or pyrazoles 5 or N-oxides of oxadiazines 7 as the main reaction products. The reaction mechanism is discussed.     

Oxidation of aliphatic alcohols with the lead tetraacetate—metal halide system under mechanical activation

The mechanochemical oxidation ofn-pentanol,n-hexanol, andn-octanol with the Pb(OAc)₄-MHal system (M=Li, K; Hal=Cl, Br) in the absence of a solvent affords esters. and secondary alcohols with the composition C₈H₁₇OH and C₉H₁₉OH give ketones. Published inIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 11, pp. 1870–1873, November, 2000.     

The lead tetraacetate oxidation of bisacetylhydrazones of α-dicarbonyl compounds

The oxidative cyclization of the title compounds results in generally two different kinds of products. The first, 1-(N,N-bisacetylamino)-1,2,3-triazole 7 (R³ = CH₃) is the primary product, while the second, 1-N-acetylamino-1,2,3-triazole 8 (R³ = CH₃), when observed, is obtained via hydrolysis from the former during work-up and separation of the reaction mixture. The primary products are considered as resulting from intramolecular nucleophilic attack on the acetyl group, of the presumed zwitterionic intermediate 5 (R³ = CH₃), by the N of the ambident N-acetylimine site of 5 .     

The oxidative-rearrangement of nitrogen heterocycles with lead tetraacetate and t-butyl hypochlorite

Mechanisms for the lead tetraacetate and t-butyl hypochlorite oxidation of 1,4-dihydro-3(2H)-cinnolinones and 1-amino-2-indolinones are discussed. Evidence for the lack of a nitrene intermediate is given.     

Bislactonization of unsaturated diacids using lead tetraacetate

The reaction of lead tetraacetate with unsaturated carboxylic acids (or salts) to from bislactones (γ or δ) can be controlled to produce efficiently $\text{cis}$ addition of two carboxylic oxygens to the double bond, in consonance with an initial plumbolactonization step followed by S_N2 displacement of lead.     

含噻吩基的三硅烷在辐照下的反应

通过类似的格氏反应合成了2-苯基-2-呋喃基六甲基三硅烷和2-苯基-2-噻吩基六甲基三硅烷.前者在2,3-二甲基-1,3-丁二烯存在时的光解导致正常的硅烯-烯烃加成和硅烯C-H插入反应.而噻吩基三硅烷在甲醇一环乙烷体系中被光解,产生自由基反应,我们怀疑噻吩中的硫原子对硅烷自由基有强烈的稳定作用.通过对典型的自由基反应产品的鉴定以及它的用自由基猝灭剂的猝灭产品的电子自旋共振谱也支持了这一结果.