Alkene loss from metastable methyleneimmonium ions: Unusual inverse secondary isotope effect in ion-neutral complex intermediate fragmentations
摘要:
AbstractThe mechanism of propene elimination from metastable methyleneimmonium ions is discussed. The first field‐free region fragmentations of complete sets of isotopically labelled methyleneimmonium ions (H2C = \documentclass{article}\pagestyle{empty}\begin{document}$ \mathop {\rm N}\limits^{\rm +} $\end{document}+R1R2: R1 = R2 = n‐C3H7; R1 = R2 = i‐C3H7; R1 = n ‐C3H7; R2 = C2H5; R1 = n‐C3H7; R2 = CH3; R1 = n‐C3H7; R2 = H) were used to support the mechanism presented. The relative amounts of H/D transferred are quantitatively correlated to two distinct mathematical concepts which allow information to be deduced about influences on reaction pathways that cannot be measured directly. Propene loss from the ions examined proceeds via ion‐neutral complex intermediates. For the di‐n‐propyl species rate‐determining and H/D distribution‐determining steps are clearly distinct Whereas the former corresponds to a 1,2‐hydride shift in a 1‐propyl cation coordinated to an imine moiety, the latter is equivalent to a proton transfer to the imine occurring from the 2‐propyl cation generated by the previous step. For the diisopropyl‐substituted ions which directly form the 2‐propyl cation‐containing complex, the rate‐determining hydride shift vanishes. The 2‐propyl cation‐containing complex can decompose directly or via an intermediate proton‐bridged complex. Competition of these routes is not excluded by the experimental results. Assuming a 2:1:3 distribution, a preference for the α‐ and β‐methylene of the initial n‐propyl chain as the source of the hydrogen transferred is detected for n‐propylimmonium ions containing a second alkyl chain R2. This preference shows a clear dependence on the steric influence of R2. During the transfer step isotopic substitution is found to affect the H/D distribution strongly. For the alternative route of McLafferty rearrangement leading to C2H4 loss, specific γ‐H transfer is observed.
Alkene loss from metastable methyleneimmonium ions: Unusual inverse secondary isotope effect in ion-neutral complex intermediate fragmentations
摘要:
AbstractThe mechanism of propene elimination from metastable methyleneimmonium ions is discussed. The first field‐free region fragmentations of complete sets of isotopically labelled methyleneimmonium ions (H2C = \documentclass{article}\pagestyle{empty}\begin{document}$ \mathop {\rm N}\limits^{\rm +} $\end{document}+R1R2: R1 = R2 = n‐C3H7; R1 = R2 = i‐C3H7; R1 = n ‐C3H7; R2 = C2H5; R1 = n‐C3H7; R2 = CH3; R1 = n‐C3H7; R2 = H) were used to support the mechanism presented. The relative amounts of H/D transferred are quantitatively correlated to two distinct mathematical concepts which allow information to be deduced about influences on reaction pathways that cannot be measured directly. Propene loss from the ions examined proceeds via ion‐neutral complex intermediates. For the di‐n‐propyl species rate‐determining and H/D distribution‐determining steps are clearly distinct Whereas the former corresponds to a 1,2‐hydride shift in a 1‐propyl cation coordinated to an imine moiety, the latter is equivalent to a proton transfer to the imine occurring from the 2‐propyl cation generated by the previous step. For the diisopropyl‐substituted ions which directly form the 2‐propyl cation‐containing complex, the rate‐determining hydride shift vanishes. The 2‐propyl cation‐containing complex can decompose directly or via an intermediate proton‐bridged complex. Competition of these routes is not excluded by the experimental results. Assuming a 2:1:3 distribution, a preference for the α‐ and β‐methylene of the initial n‐propyl chain as the source of the hydrogen transferred is detected for n‐propylimmonium ions containing a second alkyl chain R2. This preference shows a clear dependence on the steric influence of R2. During the transfer step isotopic substitution is found to affect the H/D distribution strongly. For the alternative route of McLafferty rearrangement leading to C2H4 loss, specific γ‐H transfer is observed.
A compound of general Formula (I) having histone deacetylase (HDAC) and/or Cyclin-dependent kinase (CDK) inhibitory activity, a pharmaceutical composition comprising the compound, and a method useful to treat diseases using the compound.
[EN] NOVEL CYCLOSPORIN DERIVATIVES AND USES THEREOF<br/>[FR] NOUVEAUX DÉRIVÉS DE CYCLOSPORINE ET LEURS UTILISATIONS
申请人:S&T GLOBAL INC
公开号:WO2017200984A1
公开(公告)日:2017-11-23
A compound of the Formula (I) is disclosed: (I) or pharmaceutically acceptable salt thereof, wherein the symbols are as defined in the specification. Also described are a pharmaceutical composition comprising the same and a method for treating or preventing viral infections, inflammation, dry eye, central nervous disorders, cardiovascular diseases, cancer, obesity, diabetes, muscular dystrophy, lung, and liver, and kindey diseases, and hair loss using the same.
CYCLOALKYLIDENE AND HETEROCYCLOALKYLIDENE INHIBITOR COMPOUNDS
申请人:Melvin, JR. Lawrence S.
公开号:US20100022543A1
公开(公告)日:2010-01-28
The present invention provides a compound of general Formula (I) having histone deacetylase (HDAC) inhibitory activity, a pharmaceutical composition comprising the compound, and a method useful to treat diseases using the compound.
[EN] COMBINATIONS OF HEPATITIS C VIRUS INHIBITORS<br/>[FR] ASSOCIATIONS D'INHIBITEURS DU VIRUS DE L'HÉPATITE C
申请人:BRISTOL MYERS SQUIBB CO
公开号:WO2015005901A1
公开(公告)日:2015-01-15
The present disclosure is generally directed to antiviral compounds, and more specifically directed to combinations of compounds which can inhibit the function of the NS5A protein encoded by Hepatitis C virus (HCV), compositions comprising such combinations, and methods for inhibiting the function of the NS5A protein.