Marie-Josèphe Brienne

Chirality directed self-assembly. Resolution of 2,5-diazabicyclo[2.2.2]octane-3,6-dione and crystal structures of its racemic and (−) enantiomeric forms

The chiral bicyclic bis-lactam 1 has been resolved and the crystal structures of the racemate (±)-1 and of enantiomerically pure (−)-1 have been determined. They show that the chiral nature of the substance determines the supramolecular architecture generated by hydrogen bonding self-assembly, giving an infinite zig-zag chain for the racemate and a cyclic tetramer for the enantiomer.

Macroscopic expression of molecular recognition. Supramolecular liquid crystalline phases induced by association of complementary heterocyclic components

Whereas the pure compounds are non-mesogenic, equimolar mixtures of the complementary components (5)–(7) and (11) present a liquid crystalline phase that may be attributed to the formation of the mesogenic supramolecular species (12).

Optical resolution of (±)-N-acylnorfenfluramine derivatives by preferential crystallization

Abstract Three stable and one unstable conglomerates (i. e. eutectic mixtures of D and L crystals) were found among nine synthesized (±)-N-acylnorfenfluramine derivatives. Optical resolution of the stable conglomerates could be achieved by preferential crystallization method only under nonisothermal conditions.

Synthese commode d'hydrocarbures nematiques

Abstract A short and simple synthesis of nematic polycyclic hydrocarbon is described. In the key step, the dialkylated aromatic precursors are perhydrogenated under equilibrating conditions. The desired (all-trans) isomer which is the major product of the reaction is readily obtained by crystallization.

Synthesis of biologically active fluorescent phorbol esters

Abstract Pure fluorescent derivatives of 12-O-tetradecanoyl phorbol-13-O-acetate (TPA), labeled in the tetradecanoyl chain, are synthesized by two ways: 1) from both enantiomers of β-N-dansylaminotetradecanoic acid which requires the resolution of the (±) β-aminoacid precursor; 2) from an achiral fluorescent chain derived from 3-azatetradecanoic acid. The new phorbol derivatives retain the main biological activity of TPA.

A simple and versatile synthesis of substituted ethynesulfonamides

Abstract A variety of substituted 2-arylethynesulfonamides were prepared by a two-step sequence: 1. preparation of 2-oxo-2-arylethanesulfonamides by reaction of the appropriate methanesulfonamide carbanion with a substituted benzoic ester, 2. dehydration of the resulting ketone by 2-chloro-N-methylpyridinium iodide / NEt3.

Direct Visualization by Fluorescence Videomicroscopy of the Subcellular Localization of a New Derivative of Phorbol-12,13-Dibutanoate

A new fluorescent phorbol ester derivative, dansylaza-PDB, was synthesized by the esterification of a phorbol moeity by N-dansyl-methylglycine and butyric acid. The binding of dansylaza-PDB to intact

Evidence of Polymorphism in the Case of a Substituted Imidazo-Thiazol

Abstract Physico-chemical and structural studies of 6-phenyl-2,3,5,6-tetrahydro-imidazo [2,1b] thiazol are described.

Racemic Cis-π-Camphanic Acid. Unusual Solid State Transformation of a Conglomerate into a Plastic Phase

Abstract The phase diagram between the enantiomers of cis-π-camphanic acid has been reexamined by differential scanning calorimetry (DSC). The phase diagram is that of a conglomerate (a mechanical mixture of the crystals of the enantiomers) which transforms into a plastic phase before melting. Despite anomalous thermograms observed on first heating, the existence of a solid solution intermediate between the conglomerate and the plastic phase is not confirmed. At the transition, both an orientational disorder and a molecular diffusion (leading to a chiral disorder) take place. These features are in agreement with the X-ray structure (space group P61) of the low-temperature form of the enantiomer. This structure suggests an hexagonal compact stacking for the plastic phase.