From Diethyl Tellurium

When diethyl tellurium was heated with triethylsilane at 200° for seven hours, or with triethylgermane at 140° for seven hours, the Te — C bond was cleaved, ethane liberated, and mixtures of ethyl triethylsilyl tellurium his[triethylsilyl] tellurium or ethyl triethylgermyl telluriumjhis[triethylgermyl] tellurium were formed . However, triethylstannane and diethyl tellurium yieled only bis[triethylstannyl] tellurium even at 20° . 

Irgolic Organo-tellurium Compounds without a C,Te-Bond 

From Bis[triethyl ilyl] Tellurium, Bis[triethylgermyl] Tellurium, and Similar Compounds 

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Telluraxanthene Bis(2-bromophenyl)methane (3.33 g, 1.02 mmol) is dissolved in 300 tuL of absolute diethyl ether and, under dry nitrogen, 22 mL (36.1 mmol) of a 15% solution of n-butyllithium in hexane are added dropwise. The mixture is heated under reflux for 0.5 h, cooled to 20°C and 1.8 g (14.1 mmol) of finely powdered tellurium are added. The resultant mixture is heated under reflux for 2 h and then poured into ice/water. The mixture is extracted with chloroform, the extract is filtered and the solvent is evaporated in a rotatory evaporator at 20°C under aspirator vacuum. The residue is recrystallized from diethyl ether/petroleum ether after addition of activated charcoal. Yield 1.42 g (47%) m.p. 151°C. 

Bis[triphcnylstannyl] Tellurium4 A solution of sodium hydrogen telluride is prepared from tellurium and sodium borohydride in aqueous ethanol. A benzene solution of chlorotriphenylstannane (2 mol/mol of tellurium) is added dropwise, the benzene layer is separated, and evaporated to dryness. The residue is recrystallized several times from diethyl ether/hexane m.p. 150°. 

DiethylsQyl Ethyl Tellurium1 Under an inert atmosphere, 0.7 g (100 mmol) of lithium in small pieces, 2.91 g (9.3 mmol) of diethyl tellurium, and 25 ml of diethyl ether are shaken at 20 for 4 h. The mixture is then filtered, and 2.37 g (19.3 mmol) of chlorodiethylsilane dissolved in 20 ml of diethyl ether are added to the filtrate. The mixture is shaken for 1 h at 20°, heated at 50° for 1.5 h, and diethyl ether is distilled oflf. 30 ml of hexane are added to the residue, precipitated lithium chloride is filtered off, hexane is distilled from the filtrate, and the residue is distilled under reduced pressure in an inert atmosphere yield 3.1 g (68%) b.p. 60°/5 torr. 

Bis[4-methoxyphenyl] Ditellurium1 Sodium borohydride (81 mg, 2.2 mmol) in 3 ml ethanol is added to 670 mg (2.0 mmol) of 4-methoxyphenyl phenylethynyl tellurium in 10 ml ethanol at 40°. The solution is stirred for 10 min then 0.5 ml water and 0.5 ml of 10% aqueous sodium hydroxide are added. The mixture is cooled to 0J and stirred for 10 min. The mixture is then diluted with 30 ml diethyl ether, then washed with brine, and the organic layer separated, dried with anhydrous magnesium sulfate, filtered, and the solvent evaporated from the filtrate. Phenylacctylene iscautiously evaporated at reduced pressure and collected in a trap cooled to — 78°. The residue is recrystallized from diethyl ether yield 95% m.p. 58°. 

Bis[4-acetylphenyl] Ditellurium [Grignard Method] 1 The Grignard reagent is prepared from 4.09 g (0.0165 mol) of the 1,2-dihydroxycthane acetal of 4-acetylbromobenzene in 50 ml of tetrahydrofuran and the solution cooled to 0°. 3.15 g (0.025 mol) of powdered tellurium are added and the mixture is stirred in the flask, which is open to the atmosphere, for 10-15 h. 4 Molar aqueous hydrochloric acid is added to pH 2.5 and the ditcllurium compound is extracted with three 50 ml portions of diethyl ether. The combined extracts arc filtered, dried with sodium sulfate, the solvent is evaporated, and the residue is recryslallized from diethyl ether yield 0.36 g (9%, based on bromoacetal) m.p. 104-106°. 

Equimolar quantities of tellurium tetrachloride and 3,3-bis[chloromercuro]-2,4-pentanedione in refluxing 1,4-dioxane produced 3-(chloromercuro)-2,4-dioxo-3-pentyl tellurium trichloride. The brown solid (recrystallized from diethyl ether) retained two molecules of dioxane that are slowly given off on storage9. 

Ethyl Vinyl Tellurium2 A mixture of 2.8 g (22 mmol) tellurium, 1.1 g (10 mmol) ethyl bromide, 48.7 g (868 mmol) potassium hydroxide, 24.7 g (130 mmol) tin(II) chloride, and 150 ml water are heated in a 1 -l rotating autoclave under an acetylene pressure of 15 atm for 5 h at 105-115c. The lower organic layer is separated from the reaction mixture, dried with potassium hydroxide, and fractionated at 1 torr. According to GLC data, the material collected in a trap cooled at — 70° contains 1.27 g (7%) ethyl vinyl tellurium, 10 g (55%) divinyl tellurium, and 0.11 g (6%) diethyl tellurium. Ethyl vinyl tellurium boiled at 138 7720 torr. 

Tellurium tetrachloride and tetraaryl tin compounds reacted under similar conditions to give diphenyl tellurium dichloride (75% yield)2,3 and bis[4-methylphenyl tellurium dichloride (86% yield)4. Tellurium tetraiodide and tetraphenyl tin reacted to give diphenyl tellurium diiodide (m.p. 236°) in only 20% yield1. Tetraethyl tin and tellurium tetrahalides produced reaction mixtures from which the diethyl tellurium dihalides could not be isolated1. 

Dihydroxyphenyl4-MethoxyphenylTellnrium Dichloride1 0.34 g(l mmol)of4-methoxyphenyl tellurium trichloride and 0.22 g (2 mmol) of 1,3-dihydroxybenzene are dissolved in a small volume of methanol. The solution is allowed to stand overnight at 20°, almost all of the solvent is then evaporated, and the deposited crystals are collected and recrystallizcd from diethyl ether/petroleum ether (b.p. 50-70°) yield 0.29 g (70%) m.p. 183° (dec.). 

Dihydroxyplicnyl 4-Methoxyphenyl Tellurium Dibromide6 0.41 g (I mmol) of 2,4-dihydroxyphenyl 4-methoxyphenyl tellurium dichloride is dissolved in a small volume of ethanol and an excess of 40% hydrobromic acid is added. The mixture is stirred at 20°. The yellow precipitate is filtered off, washed with dilute hydrobromic acid, and dried yield 0.50 g (100%) m.p. 180° (dec from diethyl ether/petroleum ether). 

Diethyl Tellurium Chloride Hydroxide4 Diethyl tellurium dichloride is added to an excess of aqueous ammonia and the mixture is carefully heated until the tellurium compound has dissolved. The solution is then concentrated until the product crystallizes. The product is recrystallized from ethanol. 

A few diorgano tellurium hydroxide (hydrogen) sulfates are reported in the older literature. Diethyl tellurium hydroxide sulfates were claimed to have been produced from the hydroxide chloride and silver sulfate1 and from the dihydroxide and sulfuric acid2. Several ill-defined compounds that could be or could contain hydroxide hydrogen sulfates were obtained when dibenzo-l,4-oxatellurin or its 10,10-diacetate were treated with sulfuric acid3. 

Organo Vinyl Tellurium (from Vinyl Tellurium Iodides) A solution of the vinyl tellurium iodide, prepared by addition of 0.25 g (1.0 mmol) iodine in benzene to the divinyl ditelluride (1.0 mmol) in 5 ml tetrahydrofuran at 0° under nitrogen, is added dropwise to a solution of the organo magnesium bromide in 10 m/ tetrahydrofuran at 0°. The mixture is stirred at 20° for 1 h, hydrolyzed with a saturated aqueous solution of ammonium chloride, extracted with diethyl ether, the extract dried with magnesium sulfate and evaporated. The product is chromatographed on silica gel with petroleum ether (30-60°)/ethyl acetate (9 1) as eluent. The following compounds were prepared in this manner (yields in parentheses are for the reactions with vinyl tellurium iodides) ... 

Figure 10.46 Tellurium diethyldithiocarbamate (TeDEC) is produced from diethyl amine, carbon disulfide, and a tellurium salt...

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