Structure du méthyl-3 phénylamino-4 phényl-5 triazole-1,2,4

The crystal structure or 3-methyl-4-phenylamino-5-phenyl-1,2,4-triazole has been determined by X-ray diffraction. It allows one to choose between the two reaction mechanisms which can be taken into account for the reaction of hydrazine upon N-acylated hydrezonates.     

Isomerès optiques du naftidrofuryl ( = 2-[(naphth-1-yl)méthyl]-3-(tétrahydrofur-2-yl)propanoate de 2-(diéthylamino) éthyle)

Optical Isomers of Naftidrofuryl( = 2-(Diethylamino)ethyl 2-[(Naphth-1-yl)methyl]-3-(tetrahydrofur-2-yl)propanoate) The four optical isomers of naftidrofuryl ( 1 ) were prepared in two ways, by separation and resolution of the two diastereoisomeric racemates and by synthesis from the enantiomers of tetrahydrofuran-2-methanol ( 6 ); see Scheme}. The absolute configuration of one of the isomer as a tartrate monohydrate was established by X-ray crystallography thus allowing the deduction of the absolute configurations of the other three optical isomers.     

Synthèse de 3,5-divinylidènepipéridines N-substituées à partir du 1,7-bis(triméthylsilyl)hepta-2,5-diyne et applications

The 1,7-bis(trimethylsilyl)hepta-2,5-diyne reacts with iminium ions generated in situ from primary alkyl- or primary functional amines by a double aminomethylation–desilylation process leading to N-substituted 3,5-divinylidenepiperidines.

Résumé

Le 1,7-bis(triméthylsilyl)hepta-2,5-diyne réagit avec les ions iminium générés in situ à partir d'alkylamines primaires ou d'amines primaires fonctionnelles pour conduire à des 3,5-divinylidènepipéridines N-substituées via un double processus d'aminométhylation–désilylation.     

Migration 1,2 d''un groupe triméthylsilyle au niveau d''un cation vinylique: synthèse de diènes conjugués silylés à partir de bis(triméthylsilyl)-1,4 alcynes-2

Alkyl -substituted 1,4-bis(trimethylsilyl)-2-alkynes react with electrophilic reagents to give silylated conjugated dienes, which result from a 1,2-shift of a trimethylsilyl group to a vinylic cationic center.