ADDITIONS DES FONCTIONS SUR LA DOUBLE LIAISON DES VINYL SPIROPHOSPHORANES SYNTHÈSE DES α ET β AMINO SPIROPHOSPHORANES ALCOOLYSE DE LA LIAISON P—C DANS LES COMPOSÉS D'ADDITION OBTENUS

Abstract

Addition of amines and of hydrogenphosphonates on the carbon-carbon double bond belonging to vinyl-phosphoranes is examined. The stereochemistry and reactivity of the saturated adducts obtained is rationalized. Alcoholis of the P—C bond is also studied.     

Cd3(P3O9)2 · 14H2O. II—ETUDE DE L'EAU AU MOYEN DE LA RESONANCE MAGNETIQUE PROTONIQUE SUR POUDRE

Abstract

Cadmium trimetaphosphate tetradecahydrate powder has been studied by ¹H nuclear magnetic resonance between ?191 and 60°C. The spectra includes one contribution from molecular water and one contribution from H atoms belonging to “OH” groups. The formula which agrees with these results is Cd₃(OH) _n (P₃O₉)₂H _n · (14- _n )H₂O; it seems that n increases with increasing values of temperature.

L'étude par résonance magnétique du proton du trimétaphosphate de cadmium tetradécahydraté en poudre a été faite entre ?191 et +60°C. Le spectre comporte une contribution d'eau moléculaire et une contribution d'atomes H appartenant à des groupes OH. La formule en accord avec ces résultats est Cd₃(OH) _n (P₃O₉)₂H _n · (14- _n )H₂O, o[ugrave] n croit vraisemblablement avec la température.     

ACTION DES HYDRAZINES ET DE L'HYDROXYLAMINE SUR QUELQUES PHOSPHONATES β, β-BIFONCTIONNALISES: SYNTHESE DE PHOSPHONOAMINOPYRAZOLES ET ISOXAZOLES

Abstract

Reaction of hydrazines and hydroxylamine with β, β-bifunctionalized phosphonates 1 and 1′ leads to phosphoaminopyrazoles and isoxazoles 2 3, 4 and 5. The structure of all obtained products was confirmed by NMR and IR spectroscopy.     

Carbohydrate hydration: heavy water complexes of α and β anomers of glucose, galactose, fucose and xylose

The singly and doubly hydrated complexes of the α and β anomers of a systematically varied set of monosaccharides, O-phenyl D-gluco-, D-galacto-, L-fuco- and D-xylopyranoside, have been generated in a cold molecular beam and probed through infrared-ultraviolet double resonance ion-dip (IRID) spectroscopy coupled with quantum mechanical calculations. A new 'twist' has been introduced by isotopic substitution, replacing H(2)O by D(2)O to separate the carbohydrate (OH) and hydrate (OD) vibrational signatures and also to relieve spectral congestion. The new spectroscopic and computational results have exposed subtle aspects of the intermolecular interactions which influence the finer details of their preferred structures, including the competing controls exerted by co-operative hydrogen bonding, bi-furcated and OH-π hydrogen bonding, stereoelectronic changes associated with the anomeric effect, and dispersion interactions. They also reassert the operation of general 'working rules' governing conformational change and regioselectivity in both singly and doubly hydrated monosaccharides.     

A new practical synthesis of silyl enol ethers : II. From α,β-unsaturated aldehydes and ketones

In acetonitrile as the solvent and in the presence of a tertiary amine the trimethylchlorosilane/sodium iodide (trimethyliodosilane “in situ”) reagent provides the corresponding siloxy dienes when reacted with α,β-unsaturated series. These reactions occurs via the formation of 1,2 or -1,4 onium salt intermediates.     

A review of: “Particle-Size Distribution II: Assessment and Characterization (ACS Symposium Series 472; Provder,T”, Ed.; American Chemical Society: Washington, 1991. pp. xiii+407 $89.95.

ABSTRACT

An automated set-up is described which permits the fast determination of the composition limits of isotropic microemulsion phases of ternary (water/oil/surfactant) systems. It is especially well suited for the investigation of systems including nonionic surfactants, which are very sensitive to temperature changes.

Four systems have been tested including hydrogenated as well as fluorinated surfactants and oils. Both direct and inverse microemulsion phases have been chosen for these investigations.

The results obtained and their comparison with previously reported diagrams are used to draw some general conclusions concerning the advantages and limits of an automatic procedure. It appears that the recordings obtained with such procedures are particularly easy to interpret for certain types of systems for which very neat turbidity changes are observed (case of reverse fluorinated systems for instance). For other systems (those for which there exists a liquid-crystalline phase for instance) care must be taken when interpreting the turbidity vs temperature curve.

The method is particularly useful when dealing with expensive products for which one cannot afford to prepare a sealed ampoule for each point of interest in the phase diagram.