Actions of bisnucleophiles on (E)-3-[3-(2-Hydroxyaryl)-3-oxoprop-1-en-1-yl]chromones: versatile transformations into oxygen-and nitrogen-containing heterocycles

The transformations of (E)-3-[3-(2-hydroxyaryl)-3-oxoprop- 1-en-1-yl]chromones in the presence of methylhydrazine and aromatic bisnucleophiles are described. The reactions generally lead to chromone ring transformation via pyrone ring-opening and heterocyclization to give novel diazoles and (Z)-3-aminomethylenechromanones, respectively. Piperazine catalyzes chromanone ring closure of the starting substrate to afford chromone–chromanone dyads

Conformational-dependent reaction mechanism: case of acid hydrolysis of N-benzoyl-9-azabicyclo[6.1.0]non-4-ene

Quantum chemical studies of the acid hydrolysis of cis-cis-N-benzoyl-9-azabicyclo[6.1.0]non-4-ene in vacuum and sulfuric acid solution have been carried out. Conformational analysis of reactant and intermediates were done at DFT level of calculations, using different basis sets. Transition states were identified and IRC calculations were done at the same level. In the first step of the reaction, the protonation occurs preferentially on the nitrogen atom. Three products are obtained. The type of mechanism: stepwise or concerted, depends on the stable conformers and the cleaved N-C bond. The main conclusion is that the products of the reaction depend on the nature of the stable conformer of reactant.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author

Part 13: Synthesis and biological evaluation of piperazine derivatives with dual anti-PAF and anti-HIV-1 or pure antiretroviral activity

HIV-1 infection of the brain and PAF neurotoxicity are implicated in AIDS dementia complex. We previously reported that a trisubstituted piperazine derivative is able to diminish both HIV-1 replication in monocyte-derived macrophages and PAF-induced platelet aggregation. We report in this work new compounds obtained by modifying its piperazine substituents. The structure-activity relationship study shows that a better dual activity or even pure antiretroviral compounds can be obtained in this series. (c) 2006 Elsevier Ltd. All rights reserved