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Le benzo(b)tellurophene est obtenu a partir de l'o-methyl tellurobenzaldehyde par la suite de reactions suivantes: quaternisation avec l'acide bromacetique, dequaternisation par chauffage du sel de telluronium, cyclisation en acide benzo(b)tellurophene carboxylique-2 et enfin decarboxylation. Les spectres IR, UV, RMN et de masse confirment la structure du benzo(b)tellurophene qui a ete egalement caracterise par sa T.N.F, son picrate et ses composes d'addition avec les halogenes.

L'o-methyltelluroacetophenone est preparee par reaction du lithium sur l'(o-iodo phenyl)-2 methyl-2 dioxolane-1,3, suivie successivement de la condensation avec le tellure et l'Iodure de methyle. La condensation de cette substance avec le benzaldehyde conduit au (cinnamoyl-2 phenyl) methyltellurure qui peut etre cyclise en telluroflavanone. Le produit principal de la reaction est cependant le (cinnamoyl-2 phenyl) bromure de tellurenyle.

La reaction de condensation entre les organolithiques aromatiques et le tellure commercial permet de preparer des ditellurures aromatiques (Ar-Te-Te-Ar) et des telluroethers arylaliphatiques (Ar-Te-C4H9) suivant que l'organolithique est prepare par reaction directe du lithium metallique ou par reaction d'interconversion au moyen du butyllithium sur un derive halogene aromatique. A partir des telluroethers du type butylique il est possible de preparer les ditellurures aromatiques correspondants par reaction de dequaternisation dans la pyridine des sels de telluronium Ar-TeX2-C4H9. La reduction des ditellurures aromatiques en tellurophenolates de sodium correspondants et la condensation de ces derniers avec un derive halogene R-X constituent une methode particulierement souple pour la preparation de substances du type Ar-Te-R dans lesquelles la nature du groupement R peut etre choisie en fonction de la destination finale de la molecule.

Nous decrivons une methode de preparation des tellurolbenzoates d'aryle et des tellurolbenzoates d'alcoyle differemment substitues en vue d'etudier en spectrographie infrarouge la position du carbonyle de ce groupement fonctionnel. La synthese mentionnee est basee sur la condensation de tellurophenolates soit avec des chlorures d'acides aromatiques soit avec des anhydrides d'acides aliphatiques. La transposition du principe de la methode a des telluroalcoolates n'a pu etre realisee avec succes.

General preparation and chemical properties of ortho carbonyl benzene tellurenyl halides are reported. The cis conformation of the oxygen of the carbonyl group and the tellurium atom is in all cases detected by NMR and IR spectroscopies.

3-substituted benzo (b) tellurophenes can be obtained through Wittig or Wittig-Horner reaction on 2 H-benzo (b) tellurophene-3-one (telluroindoxyl). This reaction shows a partial isomerisation specific of the tellurium series, due to breaking of Te-CH2 bond. The products so obtained can lead to various mono 3-substituted derivatives (CH3, CHO, CH2OH, COOH, COOCH3, CN, CONH2). Reaction of triphenylphosphin/TeX4 on the same substrate leads to 3-chloro and 3-bromo benzo (b) tellurophenes, which could not be obtained by halogenation of the basic heterocycle. Acetylation of benzo (b) tellurophene with Ac2O/CF3COOH leads to a mixture 76/24 of 2-acetyl and 3-acetylbenzo (b) tellurophenes, which could be separated through thin-layer chromatography.

In an attempt to rationalize a synthesis of penicillin analogs modified at C(3), we have isolated the 3R(β)-carbinolamide derivative 4a. The trityl substituent on N(6′) seems to be responsible for the inversion of configuration which occurs at C(3) during the acid hydrolysis of the isocyanate intermediate. An hydrogen bond is formed on the β-face of the bell-shaped bicyclic skeleton between the N(6′)-nitrogen lone pair and the C(3) hydroxyl group. On standing, the carbinolamide analog slowly isomerizes to its expanded bicyclic isomer 4b, but the starting material may be easily recovered by treatment with acid. The postulated intermediate during isomerization, i.e., the open aldehyde form, does not accumulate. Substitutions of the hydroxyl group at C(3) lead to a variety of compounds with the biologically active 3S(α) configuration. These may be used to study the importance of the carboxyl group of penicillins in their interaction with β-lactamases at the molecular level.

In an attempt to rationalize a synthesis of penicillin analogs modified at C(3), we have isolated the 3R(β)-carbinolamide derivative 4a. The trityl substituent on N(6′) seems to be responsible for the inversion of configuration which occurs at C(3) during the acid hydrolysis of the isocyanate intermediate. An hydrogen bond is formed on the β-face of the bell-shaped bicyclic skeleton between the N(6′)-nitrogen lone pair and the C(3) hydroxyl group. On standing, the carbinolamide analog slowly isomerizes to its expanded bicyclic isomer 4b, but the starting material may be easily recovered by treatment with acid. The postulated intermediate during isomerization, i.e., the open aldehyde form, does not accumulate. Substitutions of the hydroxyl group at C(3) lead to a variety of compounds with the biologically active 3S(α) configuration. These may be used to study the importance of the carboxyl group of penicillins in their interaction with β-lactamases at the molecular level.

A rapid and easy synthesis of tritium-labelled β-iodopenicillanate, an efficient inactivator of serine β-lactamase, is described. This method involves only three reaction steps after the introduction of the label in the molecule with an overall yield of 16 %.

A general procedure for Te-alkylated tellurolesters synthesis is reported. The carbonyl i.r. frequencies and 13 C chemical shifts of these compounds are compared to the O, S and Se analogs. The origin of the electronic interaction between the carbonyl group and the heteroatom is shown to depend on this latter nature: whereas a combination of both inductive and mesomeric effects is to be taken into account for O. This effect is mainly inductive for Se and Te. In the case of S-compounds, no such a simple model can be involved. The reason of which might be the participation of the 3d-orbitals to the electronic system. Moreover, the previously reported Te heavy atom effect has been detected on the α methylene groups exclusively.

77Se and 125Te chemical shifts have been measured for o-halogenated seleno- and telluro-phenetoles. Correlations exist between these parameters and the halogen electronegativities or the 13C chemical shifts, except for the fluorine derivatives. The chalcogen shifts are related to the shifts of various nuclei in halobenzene derivatives, namely 1H in benzenes, 13C in toluenes, 15N in anilines and 19F in fluorobenzenes. 77Se and 125Te chemical shifts are correlated in the o-halogenated seleno- and telluro-phenetoles and in chalcogen analogues of o-methoxy-selenoanisole and -tellurophenetole: Δδ(Te) = 1.60Δδ(Se). The observed gradient is close to values previously reported for other selenides and tellurides, but differs from the value observed in heterocycles. This observation is discussed.

When treated with alkylithium, the two cis and trans isomers of the title compounds react quite differently: while the trans compounds undergo a classical metallation, in the cis ones, a ring opening occurs in the selenophenic moiety. The u.v. spectra of the two isomers are also clearly distinguished. Selenium 77 magnetic resonance, enhanced by CNDO calculations, has also shown different behaviours, opposite to proton and 13 C magnetic resonances. In fact, proton magnetic resonance measurements have evidenced a great analogy between the title compounds and both the thiophen and benzo(b) thiophen series.

Resume Au cours d'essais de cyclisation electrophile. le chlorure d'o-phenyl telluro benzoyle ne se cyclise pas en telluroxanthone. mais s'isomerise en halogenure de tellurenyle. l' o -chlorotelluro benzophenone. due a une carbodetelluration intramoleculaire. Une coupure de la meme liaison C aromatique -tellure se realise aussi par protonolyse. Cette derniere reaction conduit a une methode preparative de synthese de l'acide ditellurosalicylique, base de nombreux heterocycles tellures benzocondenses.

NMR measurements ( 1 H, 13 C, 77 Se) of diphenyl dichalcogenides are reported. They confirm the molecular conformation deduced from other physical experiments. Steric inhibitions are responsible for the conformation in the Te compound, while, in the S and Se compounds, the heteroatom lone pairs interact to some extent with the π systems of the rings. More fundamental discussions of the measured parameters are made, including the somewhat controversial existence of the title compounds in solution.

A study by 13 C NMR of some esters and their chalcogen analogs is presented: R 1 C(O)XR 2 , (X  O, S, Se, Te), (R 1 , R 2  alk, ar). The chemical shifts are discussed in the scope of the mutual interaction between R 1 and R 2 through the carbonyl group and through the heteroatom. The results are in agreement with a recent study by 77 Se NMR of the selenolesters: they confirm the importance of the resonance form in these type of compounds.

In order to synthesize new tellurium heterocycles, we prepared o -halogenotellurobenzoyl chlorides. We present and discuss here the results of a 13 C NMR study of these compounds, together with other intermediates that we have isolated during our synthesis and two new tellurium heterocycles.

Results are reported of a study by 1H and 13C nuclear magnetic resonance of anisole, thioanisole, selenoanisole and telluroanisole as well as of several of their para-substituted derivatives. If these compounds are considered as substituted methyl groups, they display a behaviour analogous to that of the methyl halides. It is possible to demonstrate that a linear relation exists between the proton and the carbon chemical shifts in the anisole series as well as in the methyl halides. Although these results most frequently are interpreted in terms of electronic effects, a 'heavy atom effect' must be invoked for the tellurium compounds. The experimental results do not contradict the hypothesis that the compounds studied have a planar configuration [Journal translation]

A linear relationship was observed between the 77Se and 125Te chemical shifts in 14 model heterocycles (including 17 new data). The line slope, 1.3, is discussed in terms of Jameson and Gutowski's expression for the Ramsey paramagnetic term, σP. The shifts are also compared with the 17O chemical shifts in related compounds.

13 C NMR spectra of the title compounds have been fully assigned. The results have been compared with those relative to other chalcogenated compounds, such as anisole, phenyl benzoate, benzofuran,… and their analogs. In chalcogenochromones and -coumarines, the heteroatom lone pair delocalization spreads to some extent over the heterocyclic part of the molecules, while in chalcogenochromanones and -indoxyles, it only extends to the homocycle. This electronic effect seems also to affect the heavy atom effect exhibited by Te-containing compounds.

A general method of preparation of tellurochromanones is described by Friedel-Crafts intramolecular cyclisation of the corresponding acids. The structure was determined by chemical evidence, analysis, uv, ir and nmr spectra. The first tellurochromannols and tellurochromene are also described.

Resume Les spectres infrarouges (4000-200 cm −1 ; vapeur solide et solution dans des solvants neutres et accepteurs de protons) et Raman (4000-100 cm −1 solide et solution) des benzoselenophene et benzotellurophene ont ete enregistres. Une attribution complete des vibrations fondamentales est proposee. L'evolution des nombres d'onde des vibrations fondamentales pour une serie de benzoheterocycles monoheteroatomique C 8 H 6 X avev X = O, S, Se et Te est analysee.

The 1Hmr study of the title compounds has revealed a screw conformation, with defined interconversion processes, in good agreement with crystal structure determinations and theoretical calculations. The mesomeric effect of the heteroatom is smaller than in the anisole series, due to steric inhibitions.The 13Cmr enhances, to some extent, these conclusions. In the case of Te compounds, a heavy atom effect adds to the classical mesomeric and inductive effects to account for the experimental observations.

The crystal and molecular structure of o-formylphenyltellurenyl bromide has been determined by three-dimensional X-ray analysis. Crystals are monoclinic (P21/c) and the unit cell has the dimensions a = 12.533, b = 5.839, c = 11.706 A and β = 102.48°. The refinement of the structure by Fourier and block-diagonal matrix least-squares methods has led to a final R value of 0 081. The molecule has a planar cis configuration. The coordination of the Te(II) atom is described with the model proposed by Foss. The existence of a Te-O bond is discussed.

We report the analysis of the high-resolution proton magnetic resonance spectra of some 2-halotellurenyl-benzaldehydes (Cl, Br, I) and of 2-methyltellurobenzaldehyde, considered as ABCD spin systems. The identification of the long-range couplings in these molecules shows that they all have a ‘cis’ conformation of the aldehyde carbonyl relative to the ortho-substituent. An electronic model which explains this conformation in the case of the haloderivatives is suggested. It agrees with infra-red measurements. In the case of the methylated compound, another model is proposed to account for our observations, in agreement with the results reported by Andrieu and Ruwet for 2-methoxy, 2-methylthio- and 2-methylselenobenzaldehyde. We observed coupling of the methyl protons with the nuclei 123Te (27·0 Hz) and 125Te (32·5 Hz) in 2-methyltellurobenzaldehyde.

The frequency of the aromatic carbonyl group undergoes an important and systematic lowering when this group is fixed in ortho position of a substituent as SeCN, SeSPh, SCl, SeCl or SeBr. The interpretation of this phenomenon is discussed and attributed to a field-effect between the selenium positively polarized by induction through the electronegative substituent it is carrying, and the oxygen of the carbonyl. This effect stabilizes the cis -form, usually still more stable by steric effect; hence, the phenomenon of rotational isomerism is very rarely observed in these derivates. The intensity of the effect is discussed in function of the nature of the carbonyl and the ortho -substituent.

Resume We have studied by i.r. spectroscopy the position of the carbonyl band of various tellurolesters. We have seen a splitting of the v C0 band, attributed to a Fermi resonance. This assignment is supported by solvent and temperature effects.

We report the selenium 77 chemical shifts in twenty selenolesters R 1 -C(O)-Se-R 2 . The δ( 77 SE) variations with the nature of R 1 and R 2 are discussed within the scope of the resonance interactions between selenium and carbonyl. The most important form in the selenolesters studied seems to be

Nous decrivons la synthese, par deux methodes differentes, d'un nouvel heterocycle tellure de base, le benzisotellurazole-1,2, et nous en comparons les proprietes avec celles des analogues sulfure et selenie correspondants. Two different synthetic methods for 1,2-benzisotellurazole are described. The properties of this new heterocyclic system are compared with the analogous sulfur and selenium heterocycles.

o-Carbonyl benzeneselenenyl compounds with COCH3, CHO and COOCH3 as carbonyl functions and SeCl, SeBr, SeSCN, SeSeCN, SeCN and SeCH3 as selenium-containing groups, have been studied by 1H, 13C and 77Se NMR spectroscopy. The IR CO stretching frequencies of these compounds are also reported. If the SeCH3 derivatives are excluded, the compounds mainly adopt a planar ‘cis’ conformation, due to an interaction between the CO group and the selenium atom. The range of over 800 ppm for the observed 77Se chemical shifts makes 77Se NMR spectroscopy a powerful tool for physical organic chemists.

The 77Se chemical shifts of 79 mono- or disubstituted benzo[b]selenophenes are reported. The results in the 2- and 3-substituted derivatives closely parallel those previously obtained in the corresponding selenophenes. The measured parameters also correlate well with those measured in benzo[b]tellurophenes. The 125Te and 77Se chalcogen nuclei appear to be much more sensitive to substituent effects than the more classical nuclei. The effects of Cr(acac)3, Eu(dpm)3 and concentration on the 77Se NMR spectra are briefly discussed.

Selenium-77 magnetic resonance spectra of sulphur-selenium and selenium-selenium isosteres of phenanthrene and some of their 2-substituted derivatives have been recorded and 48 77Se chemical shifts are presented. The two isomers of the studied compounds could be differentiated because the Se nucleus is always more shielded in the ‘trans’ than in the ‘cis’ isomer, the difference varying between 10 and 40 ppm. CNDO calculations have been performed; they allow an electronic model to be proposed which accounts, at least qualitatively, for the NMR results. They also provide an electronic interpretation of the ring opening of the Se-containing ‘cis’ isomers when treated with alkyllithium.

La 2H[1]-benzotellurinnone-2 (telluro-1 coumarine), et des dihydro-3,4- chalcogeno-1 coumarines ont ete synthetisees par cyclisation intramoleculaire de l'acide ou du chlorure d'acide correspondant. Les nouveaux systemes heterocycliques sont caracterises par differentes methodes physicochimiques: ir, rmn 1H et 13C et spectrometrie de masse. 2H-(1)Benzotellurin-2 one ‘tellurocoumarin’ and 3,4-dihydrochalco-genocoumarins have been synthesized by intramolecular cyclisation of the corresponding acid or acid chloride. The new heterocylic systems were characterized by physicochemical methods, ir, 1H and 13C nmer spectroscopy and by mass spectromety.

Aus den Oximen (II) erhalt man mit Polyphosphorsaure die Cyclisierungsprodukte (III), die zu (IV) quaterniert werden.

As part of a study of the physico-chemical properties of O, S, Se and Te-containing aromatics, twelve compounds with general formula Y–C6H4–X–X–C6H4–Y, where X = S, Se and Te and Y = H, CH3, Br, Cl have been studied. The structures of seven of these (ϕ–S–S–ϕ, ϕ–Se–Se–ϕ, ϕ–Te–Te–ϕ, CH3–ϕ–S–S–ϕ–CH3, Cl–ϕ–Se–Se–ϕ–Cl, Cl–ϕ–Te–Te–ϕ–Cl, Br–ϕ–S–S–ϕ–Br) have been reported previously. The data on the other five molecules (CH3–ϕ–Se–Se–ϕ–CH3, Cl–ϕ–S–S–ϕ–Cl, Br–ϕ–Se–Se–ϕ–Br, Br–ϕ–Te–Te–ϕ–Br, CH3–ϕ–Te–Te–ϕ–CH3) are given.

Indirect evidence is provided for (a) the existence of an interaction between the Te d-orbitals and the oxygen lone pair in COR and NO2 substituted compounds and (b) the Δδ(77Se) ≈ 0.6 Δδ(125Te) relationship.

The 13C NMR signals have been assigned for some ortho-carbonyl benzene-selenenyl derivatives, COR.C6H4. Sex, where R = H, CH3, OCH3 and OC2H5 and X = Cl, Br, CN, SCN, SeCN and CH3. The effects of the nature of R and X have been discussed.