From Diaryl Telluriums Oxides

Diaryl tellurium oxides reacted with trifluoroacetamide, trichloroacetamide phenylme-thanesulfonamide, and arenesulfonamides in refluxing chloroform to produce diaryl tellurium imides. 

Diaryl Tellurium Phenylmethanesulfonimides O.OS mol of the diaryl tellurium oxide and 8.6 g (O.OS mol) of phenylmethanesulfonamidc are added to 100 m/ of anhydrous chloroform. The mixture is heated under reflux and 60 ml of chloroform arc slowly distilled off. The remaining chloroform is evaporated under vacuum and the residue is recrystallized from benzene, chloroform/hexane, chloroform/diethyl ether, or benzene/hexane/diethyl ether crude yield 100%. 

Trichloroacetonitrile, but not acetonitrile or benzonitrile, reacted with diaryl tellurium oxides in hot chloroform to give diaryl tellurium trichloroacetimides . 

The diaryl tellurium carboximides may exist in syn- and a //-forms if the N — C bond has double-bond character. The jyn-forms are stabilized by the proximity of opposite charges on the tellurium atom and the oxygen atom. Most of the diaryl tellurium trifluoroacet-imides only exist in the yn-form. However, bis[4-methoxyphenyl] tellurium trifiuoroacet-imide was isolated in both forms. When the crude reaction product was dissolved in hot benzene and the resulting solution was cooled to and kept at 10°, cubic crystals of the anti-form (m.p. 169°) precipitated. Addition of hexane to the hot filtrate precipitated the syn-form as an oil that crystallized on trituration with diethyl ether. The jyn-form melted at 81°  

Irgolic Organo Tellurium Compounds with 2 Te —C Bonds or 1 Te = C Bond 

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Diaryl tellurium hydroxide perchlorates were obtained from equimolar amounts of diaryl tellurium oxides and perchloric acid1. 

Diaryl Tellurium 3-Mercaptopropanoate3 To a solution of 0.05 mol of the diaryl tellurium oxide in 50 ml anhydrous toluene are added 0.05 mol 3-mercaptopropanoic acid. The stirred mixture is refluxed for 3 h. Water is removed by azeotropic distillation and collected in a Dean-Stark trap. The toluene is evaporated. The diphenyl derivative is purified by preparative thin-layer chromatography and column chromatography with toluene as mobile phase. The ethoxyphcnyl derivative is recrystallized from benzene and hexane. Compounds thus prepared include ... 

Diaryl tellurium oxides were found to be effective catalysts for the preparation of benzylidenearenesulfonimides from benzaldehydes and arenesulfonamides3. 

Dialkyl, alkyl aryl, and diaryl tellurium dichlorides were reduced by thiourea dioxide in a 2 molar aqueous solution of sodium hydroxide to the corresponding diorgano tellurium compounds4,5. The tellurium species actually reduced are the diorgano tellurium oxides or dihydroxides that are formed from the dichlorides in the basic medium. 

Higher-valent metal halides oxidize diaryl tellurium compounds to diaryl tellurium dihalides. Copper(II) halides can be generated in the reaction mixture from easily accessible copper(II) acetate and hydrohalic acids4. These halogenation reactions are convenient alternatives to the methods using corrosive elemental halogens or sulfuryl halides. 

Phenyl, 4-methoxyphenyl, and 4-ethoxyphenyl tellurium thiocyanates are known only in the form of their complexes with thiourea1,2 ethylenethiourea3, triphenylarsine oxide, 3-methylpyridine, 3-methylpyridine /V-oxidc, or 4-methylpyridine Af-oxide2. These compounds were prepared from the diaryl ditellurium compounds, thiocyanogen, and the ligands2. 

Strong oxidizing agents such as concentrated nitric acid eliminate both tellurium atoms from the diaryl ditellurium with concomitant nitration of the aromatic ring1. Rather unstable ditellurium derivatives such as dibenzyl ditellurium2,3 already lose both tellurium atoms upon irradiation with a mercury lamp3 or under normal light2. 

Fluorination with elemental fluorine diluted 1 20 with nitrogen was used to prepare pentafluorophenyl tellurium trifluoride from bis[pentafluorophenyl] ditellurium at — 60° with fluorotrichloromethane as the reaction medium. The yield in this reaction was 80% 4-Methoxyphenyl tellurium trifluoride was obtained by electrochemical oxidation of the diaryl ditellurium in 0.5 M hydrofluoric acid at platinum electrodes2. Bisfpentafluoroethyl] ditellurium and chlorine fluoride (1 6) reacted at — 78° to give pentafluoroethyl tellurium trifluoride, a white solid melting at 95°3. The same compound was obtained with xenon difluoride as the fluorinating agent and melted at 143°4. 

A promising method for the synthesis of unsymmctrical diorgano tellurium compounds uses carboxylic acid derivatives and diaryl ditellurium as starting materials. The carboxylic acid chloride, prepared in quantitative yield from the acid and oxalyl chloride is added slowly to a mixture of a diary] ditellurium and the sodium salt of 2-mercaptopyridine N-oxide in toluene at 35°. Under normal laboratory light the aryl tellurium radicals... 

Diaryl polonides are converted to the dibromides when they undergo reaction with Ar2TeBr2, Essentially, this is an oxidation reaction in which Po is oxidized from Po to Po and tellurium is reduced from Te to Te. Also, diaryl polonides add elemental bromine to form the dibromides. Thus, treatment of (C9Hu)2Po or (q -CioH7)2Po in benzene with bromine yields the dibromides. They can be precipitated by the addition of petroleum ether and recrystallized from benzene/petroleum ether. In a manner parallel to that just described, p-tolyl and Q -naphthylpolonium diiodides, Ar2Pol2, have been obtained by the addition of I2 to the respective diaryl polonides. 

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