Reactivite des carbenes et carbenoides issus de diazomalonates mixtes de methyle et de benzyles substitues. Synthese de composes cycloheptatrieniques

The title diazomalonates, when treated with copper powder in octane, yield lactones of 1-hydroxymethyl 7-carboxy cycloheptatrienes. The yields of cyclisation product from such diazoesters may be increased either by a gem-dimethyl grouping or by an electron rich mesomeric group attached to the benzene ring. The methoxy-cycloheptatriene compound 3d is hydrolysed to the spirodienone 8. The carbenes formed from the diazomalonates 2a and b by photolysis or thermolysis undergo Wolff rearrangement and yield insertion products into CH bonds of solvent.     

Telomeres photoreticulables—2. Synthese de telomeres photoreticulables a partir des hydroxy-2-ethyl acrylate et methacrylate et des β-cinnamoyl oxy ethyl acrylate et methacrylate

Photocrosslinkable telomers based on cinnamoyl derivatives of polyacrylates and methacrylates can be prepared either by reaction of cinnamoyl chloride with telomers of hydroxy-2-ethyl acrylate and methacrylate, or by direct telomerisation of β-cinnamoylethyl acrylate and methacrylate. The first method gives products containing at least 70% of the theoretical maximum olefinic unsaturation but with low $\text{DP}$_n [1–20]; the second method gives telomers of high $\text{DP}$_n with the maximum number of cinnamoyl side-chains.     

Action des composes organomagnesiens sur les pyrones-2-VII : Etude de la stabilite relative des hydroxy-6 dihydro-5,6 2h-pyrannes et des cetols tautomeres correspondants

In the reaction between organomagnesium compounds and 2-pyrones, the relative stability of the 6-hydroxy 5,6-dihydro 2H-pyrans and their tautomeric forms (ketols) has no influence on the reaction pathway. When ethylenic ketols are obtained, the corresponding tautomeric dihydropyranols are prepared in a selective way by reaction of nucleophilic reagents on the 3,6-dihydro-2-pyrones. In the other hand, the exclusive formation either of the dihydropyranols or of the unsatured ketols E, during these two reactions, shows up that here is no equilibrium between these two entities in the experimental conditions.     

Greffage du methacrylate de methyle et de l'acrylonitrile sur des films de poly (chlorure de vinyle) preirradies

Grafting of MAM and ANon PVC films which have previously been irradiated under vacuum or in the presence of air have been studied. After irradiation under vacuum the PVC films occlude some entrapped radicals which start the grafting and which do not give rise to any homopolymerization. The rate of grafting attains a limit at an amount of pre-irradiation of about 1 Mrad. Grafting is a maximum when the reaction is carried out at 30–40°. Irradiation in the presence of air leads to some entrapped radicals but also to some peroxides. The reaction continues for a very long time at constant velocity. The velocity of grafting increases at first with the amount of pre-irradiation, but shows a sharp maximum towards 3 Mrads and then decreases. This phenomenon is attributed to induced decomposition of the peroxides formed. The results as a whole suggest that irradiation of PVC in the presence of air leads to a peroxidation in a short chain with the formation of hydroperoxides.     

Synthese et proprietes des (hydroxy-2) dihydro-1,2 phosphorines

Benzoyl chloride with various phospholes yields acyl phospholium salts which lead to (2-hydroxy, 2-phenyl)-1,2-dihydrophosphorine oxides upon hydrolysis. These are converted into (7-phenyl)-1-oxa-2-phosphacyclohepta-4,6 dienes with catalytic amounts of sodium hydride. This general scheme fails when the phosphorus atom is substituted by a tertiobutyl group. Mechanisms and NMR data are discussed.     

Synthese de dihydroxy phenacylidene triphenylphosphoranes nouveaux precurseurs de composes flavonoides: Synthese d'hydroxy-6 et hydroxy-7 chromones.

The synthesis of two new dihydroxy phenacylidene triphenylphosphoranes from 2,4-dibenzoyloxy and 2,5-dibenzoyloxy acetophenones is described. By acylation of the hydroxyl groups of theses ylids, intramolecular of the esters carbonyl group and hydrolysis of the second esters group, some 6-hydroxy and 7-hydroxy chromones are prepared with good yields.     

Nouvolle synthcse de la dihydro-5,6 methoxy-6 2H-pyrannone-5

The α,β-ethylenic ketone 5 was obtained in 35% yield in four steps from 1. The intermediate product was a brominated ketal obtained in the form of a mixture of two isomers 6 and 7 . The stereochemistry and conformation was established by a study of the 250 MHz nmr spectra. During the dehydrobromination of 6 and 7 , a relatively easy isomerization of the α,β-ethylenic ketal occured by displacement of the double bond giving theβ,γ-ethylenic ketal 10 .     

Spectres de vibration et champs de force de valence de quelques composes π benzoate de methyle Cr(CO)3-nLn: II. Benzoate de methyle chrome tricarbonyle

A valence force field of methyl benzoate tricarbonylchromium is determined from the force field of methyl benzoate and that of hexacarbonylchromium. The results show the perturbation made both to the aromatic ring and to the carbonyl bonds by the chromiumring bond. This work is the first complete analysis of the vibrational spectra of methyl benzoate tricarbonylchromium.     

Analyse viscosimetrique des telomeres de l'acrylate d'ethyle et du chlorure de vinyle avec le tetrachlorure de carbone et le trichloroacetate de methyle

Telomers of ethylacrylate and vinylchloride with carbon tetrachloride or methyltrichloroacetate have been prepared by redox catalysis. They have the expected viscometric behaviour which depends upon the nature of the telogen. Thus viscometry can be used for determination of average molecular weight for such compounds.     

Etude des aldimines lithiees : III. Action des epoxydes et synthese d'amino-2 et d'hydroxy-2 tetrahydrofurannes

The reaction of lithiated aldimines, prepared from activated amides, with epoxides leads to good yields of 2-aminotetrahydrofurans (neutral hydrolysis) and 2-hydroxytetrahydrofurans (acid hydrolysis). Various epoxides were examined.     

Sur la non-equivalence des liaisons CH du groupement methyle dans les complexes cristallises de trans-bromotetracarbonyle methyle carbyne de chrome

The syntheses, ³¹P{¹H} NMR spectra, and a structure of “mixed” 1,5-cyclo-octadienebis(tertiary phosphine)dirhodium complexes possess a rhodiumrhodium bond, briding diphenylphosphido and two different stereochemistries around the rhodium atoms. One rhodium is tetrahedral and surrounded by four phosphorus atoms and the other rhodium (bonded to COD) is nearly planar.     

Spectres de vibration et champ de force de l'antimoniate et de l'arseniate de calcium CaSb2O6 et CaAs2O6

The i.r. and Raman spectra of the antimonate CaSb₂O₆ and arsenate CaAs₂O₆ belonging to the “PbSb₂O₆ type” structure are studied. A normal coordinate calculation permitted us to calculate and to compare their relative force fields. A comparison with results obtained for other antimony and arsenic oxides is presented.     

Spectres de vibration et champs de force de valence de quelques composes π benzoate de methyle Cr(CO)3−nLn: III. Benzoate de methyle chrome dicarbonyle selenocarbonyle

Vibrational spectra of methyl benzoatodicarbonylselenocarbonylchromium have been recorded and interpreted and a valence force field is determined. Comparison with methyl benzoatodicarbonylthiocarbonylchromium is discussed. This work shows also which vibrational modes may be used to compare donor—acceptor effect for other ligand L.     

Synthèse univoque du nitro-2 methoxy-3 benzofuranne et des naphtofurannes correspondants

3-Methoxyarenofurans were obtained from 3-counmaranone, from ts three corresponding isomeric naphtofuranones and from 7-methoxynaphtho[2,1-b]furan-1-one in good overall yields by carboxymethylation followed by saponification and subsequent decarboxylation, Their regioselective nitration in the 2-position was performed by successive treatment with t-butyllithium, trimethyltin chloride and tetranitromethane.