Acces aux dinitro-2,4 diarylamines par substitution nucleophile SNAr-limites de la reaction et application a la synthese de cyanocarbazoles

3-Cyanocarbazoles, key-intermediates in the total synthesis of pyrido [4,3-b] carbazoles, have been obtained starting from easily available materials and involving the cyclization of diarylamines. The first step of the preparation consists in a S_NAr reaction between a para substituted aniline and a chloro- (or bromo)-dinitrobenzene. This nucleophilic substitution has been found to be hindered by the steric effect of a methyl group, explained in terms of inhibition of resonance and confirmed by X-ray determination.     

Antiproliferative effects of isopentenylated coumarins isolated from Phellolophium madagascariense Baker

From the leaves of Phellolophium madagascariense Baker (Apiaceae), an endemic herb to Madagascar, three known coumarins (osthol, murraol and meranzin hydrate) have been isolated and identified. This is the first report of these compounds in this species. The structural elucidations were based on the analysis of physical and spectroscopic data. The anticancer activity of the three isolated compounds and of a synthetic sample of osthol was evaluated on L1210 mouse leukemia and on human prostatic cancer hormonosensitive LNCaP and hormonoindependent PC3 and DU145 cell lines.     

Studies on pyrrolidinone. Synthesis of aza analogs of podophyllotoxin and related compounds

The Friedel-Crafts cyclisation of N-benzhydrylpyroglutamic acids whose aromatic rings are substituted by methoxy or methylenedioxy groups gives podophyllotoxin analogs whose lactone ring was changed to a lactam.     

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.