Tellurium heterocyclic compounds

T. Chivers and D.D. Doxsee, Heterocyclic Selenium- and Tellurium-Nirtogen Compounds, Comments Inorg. Chem. 15, 109 (1993). 

Detty, M.R. (1994). The Chemistry of Heterocyclic Compounds. Tellurium-Containing Heterocycles, vol. 53. Wiley Interscience, New York... 

Heterocyclic Compounds of Quadricovalent Sulfur , D. H. Reid, in Organic Compounds of Sulphur, Selenium and Tellurium , ed. D. H. Reid, Royal Society of Chemistry, London, 1975, vol. 3, pp. 387-399. 

The heterocyclic compound 31 was obtained in 98% yield upon treatment of bis(2-hydroxymethylphenyI)tellurium dichloride with Et3N in benzene. 

There may be five different types of l-hetera-2(3)(4)-telluracyclohex-anes, three of them relating to the group of 1,4-heterocyclic systems. Of 1,3-heterocycles, only l,l-dimethyl-l-sila-3-telluracyclohexanes are described so far. Recently the first and only representative of 1,2-heterocy-clic tellurium-containing compounds has been synthesized. 

The tricyclic tellurium-containing compounds 92 are the most thoroughly studied group of the tellurium heterocycles. Moreover, phenoxatel-lurine (92, M = O) synthesized by Drew (26JCS223) some 70 years ago... 

Whereas various reactions of phenotellurazines and particularly of phe-noxatellurine have been thoroughly studied, information on the reactivity of tellurantrene is rather scarce and reactions of phenothiatellurine are practically unstudied. The chemical behavior of heterocyclic compounds 92 is determined by the presence in these tricyclic systems of two reaction centers represented by a tellurium and a second heteroatom M (NR, O, S) and also by a tendency of the activated benzene rings to enter into electrophilic substitution reactions. We shall follow this classification of reactions of tricyclic systems 92. 

M. R. Detty and M. B. O Regan, Tellurium-Containing Heterocycles, Chemistry of Heterocyclic Compounds , Wiley New York, 1994. 

Treatment of 139 with selenium and tellurium did not lead to any reaction. However, upon addition of a small amount of a triethylphosphane, the corresponding five-membered heterocyclic compounds 155 and 156 were isolated in high yield (equation 40)142. 

The three synthons E(NSO)2 (E = S, Se, Te), although isostructural, differ significantly in their chemical behavior, due mainly to the varying stability of the intermediates formed in their reactions. Specifically, the compounds Se(NSO)2 and Te(NSO)2 have enabled new procedures for the synthesis of selenium and tellurium heterocycles to be developed. For compounds such as X2Te(NSO)2 (X = F, Cl), it would be interesting to know if these compounds are also able to eliminate S02 and if so, how, inter- or in-tramolecularly. As the reaction pathways are not fully understood, more significant experimental work is needed. 

Irradiation of solutions of 2,2,3,3,5,5,6,6-octamethyl-l,4,2,3,5,6-ditelluratetrastanninane in deuterobenzene with light from a xenon lamp produced five-membered, tin-tellurium heterocycles. These compounds were not isolated. Their existence was proven by NMR spectroscopy6. 

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. 

Arenetellurolates have been used as starting materials for the preparation of heterocyclic compounds. Intramolecular nucleophilic attack by tellurium on the acetylenic carbon in 2-ethynyl-2-propenetellurolate yielded a 2,3-dihydrotellurophene derivative3 (p. 408). 

Aryl tellurium halides with suitable substituents in the ort/io-position to the tellurium atom cyclize to form heterocyclic compounds with tellurium as a ring-member. 

Organo tellurium trichlorides, in which the trichlorotclluro group is properly positioned to allow condensation with another part of the molecule, form heterocyclic compounds upon heating in high boiling point solvents. The condensations are promoted by aluminum trichloride. 

Alkyl but-3-en-1-yn-l-yl tellurium compounds add benzonitrile JV-oxide1, N-phenylbenzylidenimine TV-oxide1, and benzonitrile phenylimine2 across the carbon-carbon double bond forming heterocyclic compounds. The carbon-carbon triple bond remains unaffected. 

Alkyl aryl telluriums with appropriate functional groups in the molecule were cyclized to tellurium-containing heterocyclic compounds (Table 15, p.473). 

Diorgano tellurium dihalides were prepared in this manner from dialkyl, alkyl aryl, and diaryl tellurium compounds, and from tellurium heterocycles. However, 1-oxo-1,3-dihydro-2-benzotellurophene experienced ring cleavage when reacted with sulfuryl chloride7. 

Dimethoxyphenyl tellurium trichloride or bis [3,4-dimethoxyphenyl] ditellurium were nitrated, the ortho-nitro compound reduced to the 1,2,5-oxatellurazole with hypophospho-rousacid, and this heterocyclic compound converted to the 5,6-dimethoxy-l,3-benzotellur-azole1. 

These heterocyclic tellurium compounds react with phosphite and with C,C-multiple bonds, even below 20°, with elimination of tellurium. These compounds may, therefore, be useful as precursors of 1,3-heterodienes1. 

R. C. Elderfield, "Heterocyclic Compounds, Vol. 2, Chapter 14. Wiley, New York, 1950. R. J. S. Beer, Organic Compounds of Sulphur, Selenium and Tellurium (Sr, Reporter,... 

The addition of sodium or lithium tellurolates to carbon-carbon triple bonds can occur intramolecularly when an ethynyl group is suitably located within the molecule to allow the formation of a tellurium-containing heterocyclic compound ... 

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