Substitution nucléophile en série quinoxalinique: réactivité et effets électroniques

Doctorat en Sciencesinfo:eu-repo/semantics/nonPublishe

SUIVI ECHOGRAPHIQUE DU DEVELOPPEMENT SQUELETTIQUE FOETAL NORMAL. L'EXEMPLE DE LA COLONNE VERTEBRALE ET DES MEMBRES INFERIEURS

SCOPUS: sh.jinfo:eu-repo/semantics/publishe

6-nitro-2,3-dipiperidinoquinoxaline: Its unexpected formation from 2-chloro-7-nitroquinozaline.

Excess piperidine and 2-chloro-7-nitroquinoxaline 1 in diethyl ether give large amounts of the unexpected disubstitution product 6-nitro-2,3-di-piperidinoquinoxaline 3. The mechanism of this very unusual nucleophilic substitution of hydrogen is suggested to involve the oxidation of the dipiperidino-dihydroquinoxaline 10 by dissolved oxygen. © 1991.SCOPUS: ar.jinfo:eu-repo/semantics/publishe

Le thorax foetal en IRM

info:eu-repo/semantics/nonPublishe

Unproductive sigma and pi complexes in the reaction of 2‐chloroquinoxaline with piperidine in dimethyl sulphoxide

The rate of the reaction of 2‐chloroquinoxaline with piperidine in dimethyl sulphoxide was measured over a wide range of amine concentrations and at several temperatures. It was found that the order with respect to the nucleophile is close to 1 between 300 and 320 K, but is definitely less at lower and higher temperature. It is suggested that below 300 K an unreactive charge‐transfer complex is formed between the reactants which dissociates at higher temperatures, whereas at temperatures higher than 320 K an unproductive σ complex is formed, the concentration of which increases with increase in temperature. Copyright © 1994 John Wiley & Sons, Ltd.SCOPUS: ar.jFLWNAinfo:eu-repo/semantics/publishe

Pediatric gastrointestinal tract.

SCOPUS: re.jinfo:eu-repo/semantics/publishe

Le poumon foetal: XXIè Journées de Radiologie Pédiatrique

info:eu-repo/semantics/nonPublishe

Le diagnostic anténatal des malformations des membres par échographie obstétricale

SCOPUS: ar.jinfo:eu-repo/semantics/publishe