Synthese d'lsosélénazoles et de benzisosélénazoles-1,2

A general preparation of the isoselenazole ring by addition of bromine followed by ammonia on cis-β–methylseleno-2-propenal is described. This reaction was successfully applied to 1,2-benz-isoselenazole, a new heterocyclic system.     

Synthèse de l'analogue sélénié de la sérotonine

Starting from 2-bromo-5-methoxyacetophenone, an unambiguous synthesis of the selenium analog of serotonine is described with a 25% overall yield. Application of the Wittig reaction to selenoindoxyls appears to be a successful pathway to products of this nature.     

Thiényl- et séléniénylthiocyanates et sélénocyanates. 4. Synthèses de thiéno[2,3-d]thiazoles,de thiéno[2,3-e]thiazines et de quelques analogues sélénophéniques

Nucleophilic aromatic substitution of 3-bromo-2nitrothiophene and selenophene by thiocyanate and selenocyanate ions in dimethylsulfoxide yields 3-thienyl-and 3-selenienylthicoyanates and selenocyanates. After reduction of the nitro group, the amino derivatives undergo cyclizatrion to thieno[2,3-d]thiazoles and seleno [2,3-d]thiazoles. Also, 4H-2,3-dihydro-3-oxothieno[2,3-e]1,4-thiazine and its selenophene analog have been obtained.     

Spectrométrie de Masse D'hétérocycles Séléniés. III—Etude de la Fragmentation de Quelques Selenolo [2, 3-b] Pyridines

The mass spectra of thirteen selenolo[2,3-b]pyridine derivatives have been measured and compared with those of benzo[b]selenophene, quinoline and thieno[2,3-c]pyridine. The influence of diheteroatomic structure of the nucleus on the mechanism of fragmentation of the oxygenated substituents is discussed.     

Analyse des spectres de vibration infrarouge et Raman de benzothiazolines et de 2H-chromènes, éléments constitutifs de spiropyrannes benzothiazoliniques. Aspect synthétique

Study of infrared and Raman spectra of benzothiazolines and 2H-chromenes, constitutive parts of benzothiazolinic spiropyrans. Synthetic aspect. We have synthesized some benzothiazolines and some substituted 2 H-chromenes as models of the two halves of benzothiazolinic spiropyrans with the aim of interpretation of infrared and Raman spectra of spiropyranic structure. While doing that, we have been able to improve the synthesis method of chromenes obtained from coumarins and we have prepared new nitro-chromenes. By studying IR. and Raman spectra of the two halves of spiropyranic molecule, we could propose a rather good attribution of fondamental modes of vibration. This attribution will used as base for the interpretation of IR. and Raman spectra of a series a benzothiazolinic spiropyrans.     

Obtention de phosphore élémentaire et de phosphures de nickel par électrolyse de solutions de pentoxyde de phosphore dans des bains à base de cryolithe

By electrolysis of cryolitic solutions of P₂O₅, elementary pure phosphorus is obtained on carbon cathode and Ni phosphides on Ni cathode. The most probable mechanism of phosphorus formation in these conditions seems to be the final dissociation of P₂O₅ in P⁵⁺ and O^2? and the primary electrodic discharge of these ions.     

Etudes des sélénophènes mono et bisubstitués par Résonance Magnétique de 1H et de 13C

Proton and carbon magnetic resonance spectra of mono-and disubstituted selenophenes are investigated. The proton chemical shifts are discussed in terms of magnetic anisotropy and electric field effects of the substituents, with a view to studying the conformational equilibrium of the carbonyl group. π Electronic charges, computed by the PPP method, are correlated with the proton and carbon chemical shifts. The coupling constants between ¹³C and ¹H (1, 2 or 3 bonds) and ¹³C? ⁷⁷Se are shown to be good structural parameters and a set of substituent additivity constants is calculated.