Nitrogen and deuterium kinetic isotope effects on the Menshutkin reaction

Abstract

J. RUDZINSKI

Using 11C/14C Incoming Group and Secondary α-Deuterium KIEs To Determine How a Change in Leaving Group Alters the Structure of the Transition State of the SN2 Reactions between m-Chlorobenzyl para-Substituted Benzenesulfonates and Cyanide Ion

“…In fact, the only data that require a reactant-like transition state are the large k 11 / k 14 isotope effects. Although the authors are unable to explain why large k 11 / k 14 isotope effects are observed in this system where the best explanation of the data is a product-like transition state, it is important to note that all of the incoming group KIEs that have been reported − are normal or only very slightly inverse. In fact, the most inverse incoming group KIE was reported by Kurz et al, who found a slightly inverse nitrogen incoming group KIE of 0.9937 ± 0.0002 for the Menshutkin reaction between 4-methylpyridine and methyl triflate in acetonitrile at 25 °C.…”

High-Performance Isotope Labeling for Profiling Carboxylic Acid-Containing Metabolites in Biofluids by Mass Spectrometry

“…The synthesis of DmPABr is based on a two-step procedure modified from those described in the literature (see Supplemental Scheme S1 and Note N1 in the Supporting Information). − The first step is the dimethylation reaction, , where an isotope tag is introduced to the reagent using 13 C 2 -dimethyl sulfate for the heavy chain reagent or 12 C 2 -dimethyl sulfate for the light chain reagent. The second step involves bromation and debromation .…”

Bimolecular Hydrogen Abstraction from Phenols by Aromatic Ketone Triplets†

“…Most ketones were obtained from Sigma‐Aldrich (Milwaukee, WI) or Lancaster Synthesis (Windham, NH), and were each recrystallized from an appropriate solvent or vacuum‐distilled. 4‐Methoxy‐4′‐methylbenzophenone ( 3 ) (30), 4‐thiomethoxybenzophenone ( 9 ) (31), and 4‐dimethylaminoacetophenone ( 15 ) (32) were prepared and purified according to literature procedures, whereas 4‐methoxy‐α,α,α‐trifluoroacetophenone ( 34 ) was a generous gift from Professor P. J. Wagner. 4MP (Caledon) and phenol (Sigma‐Aldrich) were vacuum‐distilled, 4‐cyanophenol (Sigma‐Aldrich) was recrystallized from water and dried in air and 4‐methoxyphenol (Sigma‐Aldrich) was recrystallized from benzene.…”