Regiochemistry of mercury(II) oxide oxidation of unsymmetrical N,N-disubstituted hydroxylamines
作者:Sk.Asrof Ali、S.M. Azhar Hashmi、Mohammad N. Siddiqui、Mohammed I.M. Wazeer
DOI:10.1016/0040-4020(96)00904-0
日期:1996.11
Mercury(II) oxideoxidation of N,N-disubstituted hydroxylamines with the α and α′ carbon atoms containing one and two hydrogen atoms, respectively, gave aldonitrones in a highly regioselective manner. Removal of the α proton is involved in the rate determining step as shown by primary kinetic isotope effect.
The enantioselective reduction of 1,3-dipolarnitrones to hydroxylamines was achieved by Rh(III)-catalyzed asymmetric hydrogenation and transfer hydrogenation. A wide range of chiral N,N-disubstituted hydroxylamines were synthesized with up to 99 % yield and >99 % ee. Mechanistic investigations and DFT calculations were conducted to elucidate the origin of reactivity and enantioselectivity.
[EN] STERICALLY-HINDERED ALKYL HYDROXYLAMINES FOR SCAVENGING OF FREE RADICALS<br/>[FR] ALKYLHYDROXYLAMINES A EMPECHEMENT STERIQUE PERMETTANT LA DESTRUCTION DES RADICAUX LIBRES
申请人:ANGUS CHEMICAL
公开号:WO2000042079A1
公开(公告)日:2000-07-20
Free radical scavengers are formed from sterically-hindered alkylhydroxylamines. The free radical scavengers are believed useful to interrupt polymerization reactions or to facilitate storage and transportation of reactive monomers. Free radical scavengers preferably have formula (I).
[EN] DENDRIMERIC FLUORESCENT COMPOUNDS AND USE OF SUCH COMPOUNDS IN MULTI-PHOTON DEVICES OR PROCESSES<br/>[FR] COMPOSES FLUORESCENTS DENDRIMERIQUES ET UTILISATION DE TELS COMPOSES DANS LE CADRE DE PROCEDES OU DISPOSITIFS MULTIPHOTONIQUES
申请人:UNIV RENNES
公开号:WO2007080176A1
公开(公告)日:2007-07-19
[EN] Fluorescent chemical compound composed of an n-generation dendrimer, n being a non-zero integer, exhibiting: - at least one central nucleus (N) with a valency of m, selected from the group consisting of - at least one first, non-chromophoric unit (X) with a valency of m', and - at least one second unit (Y) which exhibits two-photon absorption properties, with a valency of m''. [FR] Composé chimique fluorescent constitué par un dendrimère de n génération(s), n étant un entier non nul, montrant : - au moins un noyau central (N) de valence m choisi dans le groupe constitué par - au moins un premier motif (X) non chromophorique de valence m', - au moins un deuxième motif (Y) présentant des propriétés d'absorption à deux photons, de valence m''.