Utilisation en synthese du cation iminium genere in situ par oxydation electrochimique d'amines tertiaires

The electrochemical oxidation in acetonitrile of aliphatic amines (ACH₃) in presence of a non-nucleophilic base (2,4,6-collidine) and of compounds containing weakly-activated hydrogens (RH) such as diethyl phosphonate and diethyl malonate gives the substituted derivatives ACH₂R. These compounds result from the addition of the anion R^? to the iminium cation ACH₂⁺. Such a reaction is obtained with tribenzylamine and N,N-dimethyl-p-toluidine. Moreover (CH₃)₂NCH₂-CH(CO₂C₂H₅)₂ is deaminated and gives by successive Michael reactions other substituted malonates which also react with the iminium cation (CH₃)2N⁺CH₂.     

Preparation d'oxydes de linalol par bioconversion

Microbial cyclisation of linalol(+), (?) and (±) by a nigericin-producing Streptomyces albus gives linalol oxides. Cis linalol oxide gives opposite signs for the rotatory power when measured neat or in solution.     

Reactivite des perfluoroiodoalcanes avec les carbonates et pyrocarbonates d'alcoyles en presence de couple metallique zinc-cuivre

Perfluoroalkyl iodides R_FI, in dissociating solvents, in the presence of zinc-copper couple give perfluoroorganic compounds R_FZnl, which react with alkyl carbonates and pyrocarbonates to give perfluorocarboxylic acids and perfluorocarboxylic esters of industrial interest.     

Reactivite des gem-dibromocyclopropanes. III (1) : Obtention d'oximes et d'amines α-alleniques

Gem-dibromocyclopropanic oximes are reduced by organolithium derivatives in allenic oximes and by AlLiH₄-AlCl₃ in amines.In one case a 1-hydroxypyrrole is produced.     

Etude cinetique de la catalyse par LiClO4 de la reaction d'esterification des olefines

LiClO₄ catalyses the addition of CHCl₂CO₂H to olefins (cyclopentene cycloheptene and trans-cyclo-octene). Specific salt effects are discussed in terms of general acid catalysis. This mechanism is supported by the linear relation: log k_ex = ? αH_o + β. Solvent isotope effects show a slow proton transfer. Eyring parameters are determined; ΔS* < 0. These experiments are consistent with a mechanism involving carbocation formation as the slow step.     

Deshydrogenation d'alcools en composes carbonyles par le systeme CuCl/O2/Ligande

The dehydrogenation of alcohols to the corresponding carbonyl compounds by CuCl/O₂/ligand (L) shows relative rates of dehydrogenation according to the type of alcohol used; primary or secondary benzyl alcohols > allylic alcohols or aliphatic alcohols > cyclic alcohols. The rate of this reaction was found to be dependent upon the nature of the ligands used; e.g. phenanthroline 1–10 > bipyridyl 2,2' > TMEDA, etc. When L = phenanthroline 1–10 the catalytic effect, of the system ROH/CuCl/L (3:1:1), was found to be similar to the system ROH/CuCl/L (1:2:2). The pure oxygen was replaced by air without any noticeable change in the rate of the reaction. The primary aliphatic alcohols lead to the aldehydes containing 1, 2, etc. carbon atoms fewer than the starting alcohols.     

Preparation d'esters par deshydrogenation d'alcools primaires en phase liquide catalysee par l'oxyde de cuivre - observations preliminaires

Linear primary alcohols with at least 7 carbon atoms are quite quantitatively transformed in esters, by CuO, at temperatures > 170°, without air in liquid phase. Preponderant influence of carbon in position 2 is evidenced. In the same conditions lactones are obtained from diols, and benzylic alcohols undergoes, by hydride transfer, a disproportionation into toluene, benzaldehyde and water.     

Etude de la structure K2NiF4 par la méthode des invariants,I. Cas des oxydes A2BO4

The study of the K₂NiF₄ structure by the “method of invariants” leads to the relationship

$\text{0.99615 V}\text{1}\text{3}\text{=β}{}_{\mathrm{B}}\text{+ψ}{}_{\mathrm{A}}\text{2}\text{1}\text{2}$

with V = a²c (β_B and ψ_A are invariant values associated with cations B and A) in compounds with K₂NiF₄ structures. Some values of ψ_A and examples are proposed.