Spectrometrie de Masse—VIII: Elimination D'eau Induite par Impact Electronique Dans le Tetrahydro-1,2,3,4 Naphtalenediol-1,2

Electron-impact-induced loss of a water molecule is an important fragmentation pattern of 1,2,3,4-tetrahydronaphthalene-1,2-diol. From deuterium labelling experiments the hydroxylic hydrogen atoms are shown to participate to over 70% in the water elimination. On the other hand, the C-4 hydrogen atoms are involved to the extent of 18% in this sequence. Statistical distribution, resulting from the randomisation of various hydrogen atoms, has been calculated and compared to the experimental values.     

Mass spectrometry in structural and stereochemical problems—CLXVI. The electron impact promoted fragmentation of some aliphatic 1,2-glycols

The mass spectra of nineteen aliphatic 1,2-glycols containing a variety of substituents have been recorded and mechanistic rationalizations are presented for the more important degradation processes observed. Fragmentation of the hydroxylated carbon-carbon bond in these compounds occurred to an appreciable degree often accompanied by the transfer of a hydroxylic hydrogen atom.     

New poly(ester amide)s from alkyl 2‐(carboethoxyhydroxymethyl)acrylates

The synthesis of alkyl 2‐(carboethoxyhydroxymethyl)acrylates via the Bayllis‐Hillmann reaction pathway is described. These compounds are found to be poor monomers when involved in free radical polymerizations but present an extremely high reactivity upon Michael addition with primary amines leading to a simple, mild and efficient route to the preparation of new multifunctional heterocycles and polymers with potential applications in biodegradable coatings. Real‐time NMR spectroscopy permitted monitoring the extent of the reaction sequence and determining the conversion profile of reactants and Michael adduct intermediate. Poly(ester amide)s derived from diamine and hexane bis‐2‐(carboethoxyhydroxymethyl)acrylate were synthesized at room temperature by means of a very efficient Michael addition/cyclization polymerization. These polymers display excellent adhesion to metal, glass, and paper substrates and interesting hydrolytic susceptibility. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 3182–3192, 2008     

Study of structural and electronic transport properties of Ce-doped LaMnO3

The structural and electronic transport properties of La_1−x Ce _x MnO₃ (x=0.0–1.0) have been studied. All the samples exhibit orthorhombic crystal symmetry and the unit cell volume decreases with Ce doping. They also make a metal-insulator transition (MIT) and transition temperature increases with increase in Ce concentration up to 50% doping. The system La_0.5Ce_0.5MnO₃ also exhibits MIT instead of charge-ordered state as observed in the hole doped systems of the same composition.     

Synthese totale et stereoselective du dimethyl-6,10 methylidene-9 undecene-5 (e) one-2: un des constituants de l'huile de Costus

The first total and stereoselective synthesis of (E)-6, 10 dimethyl-9 methylidene undec-5-en-2-one: a constituant of Costus Root oil is reported. It was conducted with an overall yield of 22% from 1-methyl-2-oxo-methylcyclopentane carboxylate (α-methylated Dieckmann-ester) $\text{2}$, used as a starting material.