Tellurides, heterocyclic

Diorganyl mono- and dltellurldes are the best-known classes of organic tellurium compounds comprising symmetric and unsymmetric alkyl, aryl, and alkyl-aryl tellurides. In addition to acyclic tellurides, heterocyclic aliphatic telluroethers as well as aromatic tellurophene-derivatives are known (for a review, see Ref. 36). 

The heterocyclic telluride 32 is susceptible to oxidation-addition reactions and readily adds halogen atoms under a treatment with halogens or sulfuryl chloride (93MI1). Compounds 34 were obtained in almost quantitative yields. 

Recently, a one-pot method for preparation of 2-aryl-1,5-benzotelluroazepines 60 has been developed based on the reaction of sodium 2-aminophenyltellurolate [from di(o-aminophenyl) ditelluride) with arylpropargyl aldehydes (99MI1). Considering the high affinity of supemucleophilic aryltellurolate anions to a triple bond, one may assume that at the first stage of this reaction arylvinyl tellurides 61 are formed. Cyclization of 61 spontaneously or on silica gel in a chromatographic column forms the heterocycles 60. 

Ethyleneimine reacts with (p-tolylsulfonyl)acetylene to give only the (Z)-product 115 via trans addition (equation 91), while primary and secondary aliphatic amines afford ( )-products76. With nonterminal acetylenes such as l-(ethylsulfonyl)-l-propyne, the reactions of ethyleneimine, n-propylamine and f-butylamine give mixtures of ( )- and (Z)-adducts. The double conjugate addition of sodium sulfide, selenide and telluride to bis(l-propynyl)sulfone (116) produces heterocycles (117) as illustrated in equation 9277. 

Heterocyclic selenides and tellurides selected examples 137 Antioxidant activity in functional assays 138 References 140... 

Includes bibliographical references and indexes. Contents v. 1. Primary, secondary, and tertiary phosphines, polyphosphines, and heterocyclic organo-phosphorus(III) compounds—v. 2. Phosphine oxides, sulphides, selenides, and tellurides—v. 3. Phosphonium salts, ylides, and phosphoranes. 

Less studied is another approach to derivatives of l-tellurocyclohex-3-ene 19 by which the first representatives of this heterocyclic system were obtained. It is also based on the Diels-Alder reaction, where trimethylsilyl telluropivaloate 20 is used as the dienophile (87CC820 92MI4). Compound 20 is formed, along with its isomer 20a, upon treatment of pivaloyl chloride with bis(trimethylsilyl) telluride, the 20/20a ratio being approximately 2 1. 

Likewise, no products of the anti-Michael addition were found in the reaction above. Compound 27 was obtained in 28% yield in the case of 1,5-diphenylpenta-l, 4-diyn-3-one (82JOC1968) when bis(ferf-butyldimeth-ylsilyl) telluride was used as the source of telluride anion. Heterocycle 22 (R1 = R2 = Ph) is also formed (in 19% yield). 

Although this cyclization is similar to those employed in the syntheses of oxygen and sulfur analogs of heterocycles 80 by reaction of 81 with potassium telluride does not allow the preparation of 2-phenyl derivatives of 80. 

Formation of Te-heterocycles from vinyl tellurides 91MI51. 

Recently, substituted aromatic tellurides were submitted to the tellurium-lithium exchange reaction as a way to access substituted aryllithiums,48 synthetic intermediates normally prepared by halogen-lithium exchange. Alkyltelluro heterocycles were also successfully transformed into lithium heteroaromatics.246 247... 

When di-r-butyltin dichloride was reacted with disodium3 or dilithium4 telluride a four-membered Sn2Te2 heterocyclic compound was formed. 

Tributylphosphane telluride donated its tellurium atom to decamethylsilicocene to produce dark-red prisms of a heterocyclic compound with two silicon and three tellurium atoms in the ring. The compound was characterized by single-crystal X-ray diffraction2. 

The three-membered P —Te heterocycle is formed as the main product when disodium telluride reacts with /-butyldichlorophosphine or with 1,2-di-/-butyM, 2-dichlorodiphos-phine. The heterocycle readily loses tellurium and it was not possible to isolate the compound2,3. 

The limited solubility of long-chain alkyl halides in liquid ammonia makes it advantageous to evaporate the ammonia after the disodium telluride has formed and to dissolve the residue in an appropriate organic solvent. Ethanolic solutions of disodium telluride that had been prepared in liquid ammonia were used for the synthesis of the following heterocyclic tellurium compounds1 ... 

In the reactions with the 3-morpholinyl- and the 3-(2-tetrahydropyranyl)propenes 1,1-substituted divinyl telluriums were formed as by-products in approximately 10% yield1. For heterocyclic tellurium compounds prepared from diacetylenes and sodium telluride, see p. 408. 

When sodium telluride is reacted under these conditions with 2-(chloroalkyl)-benzoyl chloride2,3 or with (2-bromomethylphenyl)-acetyl chloride4 heterocyclic tellurium compounds are formed in moderate yields. 

The reduction of the di(selenocyanato)propane 169 with sodium borohydride gave the corresponding diselenolate, which reacted with 3-chloropropan-l-thiol to give the dithiol 238 in 60% yield. A soft base like cesium carbonate in DMF was able to deprotonate the dithiol and treatment with 1,3-dibromopropane afforded the sulfur and selenium 16-membered ring heterocycles 239 in 22% yield <2000IC2558>. Bis(o-formylphenyl)telluride 241 was synthesized... 

The insertion tendency decreases in the order r-BuLi > 5-BuLi > n-BuLi > PhLi > MeLi. These insertions can be carried out by using lithium alkanides, alkenides, alkynides, and aromatic or heterocyclic lithium compounds. The lithiation should not be carried out by using alkyl halides, because the lithium tellnrolates that are formed in the reaction may react with the alkyl halide reagent to produce organyl alkyl tellurides. ... 

Di-/( rt-butyl-l-telluradiphosphirane (pale yellow needles) was synthesized by reacting l,2-di-/ftt-butyl-l,2-dichlorodiphosphane with bis(trimethylsilyl)telluride or preferably with sodium telluride in boiling pentane as shown in Scheme 17 <1993ZFA1083>. After bulb-to-bulb distillation, the yields went up to 26%. The use of solvents other than pentane resulted in a mixture of different phosphorus-tellurium heterocycles. 

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