Tellurides alcohols

Organyl tellurols are very unstable compounds owing to their extreme sensitivity to oxygen, giving the corresponding ditellurides. The first short-chain alkyltellurols (C1-C4) have been isolated as yellow liquids with an obnoxious odour, from the reaction of aluminium telluride and hydrogen telluride, respectively, with alcohols and aUcyl bromides. Aryltellurols seem not to have been isolated. As shown in Sections 3.1.3.2 and 3.2.2, aryl tellurolates are... 

Reaction of phenylacetylene with Te/KOH/SnCf A mixtnre of 6.4 g of tellurium, 42 g of potassium hydroxide, 22.6 g of SnCl2 2H20, 10.2 g of phenylacetylene, 20 mL of toluene, 60 mL of water and 1.2 g of Adogen 464 was heated (80-97°C) with vigorous stirring for 7 h. The organic layer was separated, and the aqneons layer was extracted with benzene. The benzene was removed under vacnnm. The residne was dissolved in a small amount of ether, poured into 200 mL of isopropyl alcohol, and placed in the refrigerator for 3 days. The yellow crystals of distyryl telluride (2.5 g, yield 15%) and the red needle crystals of distyryl ditelluride (0.7 g, yield 6%) were separated. 

Allenyl tellurides can be submitted to Te/Li exchange and subsequent reaction with aldehydes, giving homopropargylic alcohols. ... 

Hydrogen telluride, H2Te, generated in situ by the hydrolysis of aluminium telluride, reduces aldehydes and ketones to the corresponding alcohols. In the presence of deuterium oxide, deuterated derivatives are formed. 

Sodium hydrogen telluride reacts with epoxides, in accordance with an S 2 displacement, giving rise to telluro-alcohols. These products are useful intermediates since they are easily converted into the corresponding alcohols and ketones by treatment with nickel boride followed by oxidation (reaction (a)) or to alkenes via the corresponding tosylates (reaction b)). ... 

Epoxides bearing a leaving group in a suitable position, such as chloromethyl epoxides, react with sodium telluride (prepared by the Rongalite method), giving allyhc alcohols. ... 

A valuable alternative for enhancing the selectivity is based on telluride-mediated transposition applied to the fran -allylic alcohols." ... 

Since the starting tellurides are easily prepared (see Section 3.1.3.2) from the corresponding alkyl bromides and tellurolate ions, and -hydroxyalkyl tellurides by the opening of epoxides with the same reagents, the combined procedures furnish a method for the dehydrobromination of alkyl bromides and for the conversion of epoxides into allylic alcohols. Moreover, combining the telluroxide elimination with the methoxytelluration of olefins (see Sections 3.9.3.2 and 4.4.8.3), allylic and vinylic ethers are easily prepared. 

The above-described oxidation of allylic teUurides was applied on chiral aUyUc ferro-cenyl tellurides, giving evidence of chirality transference to the allylic alcohol. ... 

Diphenyl telluropyran-4-one (typicalprocedure)7° 120 mL (0.12 mol) of a 1.0 M solution of lithium triethylborohydride in tetrahydrofuran are added to 7.65 g (60 mmol) of powdered tellurium under nitrogen, and the mixture stirred at 20°C for 4 h. A solution of sodium ethoxide (prepared from 5.52 g (0.24 mol) of sodium and 240 mL of absolute alcohol) is added to the dilithium telluride, 13.8 g (60 mmol) of bis(phenylethynyl) ketone are dissolved in a mixture of 150 mL of tetrahydrofuran and 150 mL of 1 M sodium ethoxide in ethanol this solution is poured as quickly as possible into the deep-purple-coloured dilithium telluride soluhon. The flask containing the reaction mixture is immediately placed in a water bath at 50°C and the temperature slowly increased over 30 min until ethanol begins to condense on the side of the flask. The water bath is removed and the mixture is stirred overnight at 20°C. Dichloromethane (400 mL) is then added, the resultant mixture is washed with 800 mL of water, and the organic phase is separated and concentrated to an oil. The oil is dissolved in 600 mL of dichloromethane, and the solution is filtered through a pad of sand. The filtrate is washed with 200 mL of 2% aqueous sodium chloride soluhon, dried with anhydrous sodium sulphate, filtered and evaporated. The brownish solid residue is triturated with 20 mL of butanenitrile and the fine yellow solid is collected by filtration yield 10.9 g (51%) m.p. 126-129°C (from acetonitrile). 

Reductions. Hydrogen telluride reduces aldehydes and ketones to alcohols in satisfactory yields. The combination Al2Te2 D20 permits deutcration. H2Te reduces a,/J-cm>ncs and a,/ -cnals to the saturated carbonyl compound.1... 

Diphenyl tellurium di-iodide,1 (C6H5)2TeI2, separates as a red precipitate wThen an ether solution of iodine is added to a similar solution of diphenyl telluride. It crystallises from chloroform as small, Bordeaux-red crystals, M.pt. 237° to 238° C. on rapid heating. It is slightly soluble in benzene, toluene, ligroin or alcohols. 

This forms compact prisms, M.pt. 223° to 224° C., soluble in alcohol, chloroform or water, reduction by sulphurous acid giving the telluride. Di-p-chlorodiphenyl tellurium dibromide,1... 

Di-m-tolyl tellurium dichloride, (CH3.C6H4)2TeCl2,3 is formed when di-m-tolyl telluride in ether solution is chlorinated. The product appears as needles, sintering at 128° C. and melting at 131° to 132° C., readily soluble at the ordinary temperature in benzene, toluene, xylene, carbon disulphide, chloroform or carbon tetrachloride, less soluble in methyl or ethyl alcohol, insoluble in petroleum. When the dichloride is boiled with water a white powder separates on cooling this melts at 87° C. to a viscous oil which gradually becomes watery. Analysis shows this product to be a basic salt and not the anhydride. 

This is isolated in the usual manner from di-p-anisyl telluride. It sinters at 180° C. and melts at 183° to 184° C. The crystals consist of four-sided columns, easily soluble in warm benzene, toluene, xylene or chloroform, less soluble in alcohols, carbon disulphide or carbon tetrachloride, insoluble in petroleum ether. Boiling with water for a prolonged period yields a product of which the tellurium content lies between that of the dichloride and that of the oxide. 

Diphenyl-telluretin bromide methyl ester,2 (C6Hs)2Te(Br). CH2.COOCH3, is obtained by the interaction of diphenyl telluride and methyl bromacetate. It is a white powder, M.pt. 99° to 100° C., very soluble in hot water and separating on cooling as prismatic crystals, M.pt. 105° to 106° C. Boiling alcohol splits it up into its components. The corresponding ethyl ester melts at 63° to 64° C. 

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