25240-59-9Relevant articles and documents
Hydrogen Evolution from Telescoped Miyaura Borylation and Suzuki Couplings Utilizing Diboron Reagents: Process Safety and Hazard Considerations
Borkar, Indrakant,Brewer, Alison Campbell,Buser, Jonas Y.,Campos, Odilon,Fleming, Jeffrey,Forst, Mindy B.,Hansen, Caoimhe,Humenik, Ashley,Jeffery, Stephen,Kokitkar, Prashant B.,Kolis, Stanley P.,Lambertus, Gordon R.,Martinelli, Joseph R.,McCartan, Ciaran,Merritt, Jeremy M.,Moursy, Hossam,Murphy, Donal,Murray, Michael M.,O'Donnell, Kevin,O'Sullivan, Rita,Richardson, Gary A.,Xia, Han
, (2021/08/30)
The hazard assessment of a telescoped Miyaura borylation and Suzuki coupling reaction employing bis(pinacolato)diboron (BisPin), used in the developmental synthesis of an intermediate for abemaciclib, led to the observation of hydrogen being generated. Quantitative headspace GC and solution 11B NMR were used to show that the rapid decomposition of the excess BisPin from the borylation under the aqueous basic conditions of the Suzuki reaction was responsible for H2 generation. The moles of H2 observed were found equal to the BisPin excess, which is rationalized by mass balance and a stoichiometric reaction. The possible generation of the stoichiometric levels of H2 should be considered in hazard assessments of this class of reaction. Kinetic and process modeling was used to minimize the risk upon scale-up, and results for commercial manufacturing batches are presented, which showed good agreement with the lab scale data. Furthermore, the hydrogen evolution potentials of other common borylating agents including bisboronic acid (BBA) and pinacol borane were demonstrated.
Ruthenium-catalyzed reduction of carbon dioxide to formaldehyde
Bontemps, Sébastien,Vendier, Laure,Sabo-Etienne, Sylviane
supporting information, p. 4419 - 4425 (2014/04/03)
Functionalization of CO2 is a challenging goal and precedents exist for the generation of HCOOH, CO, CH3OH, and CH4 in mild conditions. In this series, CH2O, a very reactive molecule, remains an elementary C1 building block to be observed. Herein we report the direct observation of free formaldehyde from the borane reduction of CO2 catalyzed by a polyhydride ruthenium complex. Guided by mechanistic studies, we disclose the selective trapping of formaldehyde by in situ condensation with a primary amine into the corresponding imine in very mild conditions. Subsequent hydrolysis into amine and a formalin solution demonstrates for the first time that CO2 can be used as a C 1 feedstock to produce formaldehyde.
Kinetic rotating droplet electrochemistry: A simple and versatile method for reaction progress kinetic analysis in microliter volumes
Challier, Lylian,Miranda-Castro, Rebeca,Marchal, Damien,Noel, Vincent,Mavre, Francois,Limoges, Benoiit
, p. 14215 - 14228 (2013/10/21)
Here, we demonstrate a new generic, affordable, simple, versatile, sensitive, and easy-to-implement electrochemical kinetic method for monitoring, in real time, the progress of a chemical or biological reaction in a microdrop of a few tens of microliters, with a kinetic time resolution of ca. 1 s. The methodology is based on a fast injection and mixing of a reactant solution (1-10 μL) in a reaction droplet (15-50 μL) rapidly rotated over the surface of a nonmoving working electrode and on the recording of the ensuing transient faradaic current associated with the transformation of one of the components. Rapid rotation of the droplet was ensured mechanically by a rotating rod brought in contact atop the droplet. This simple setup makes it possible to mix reactants efficiently and rotate the droplet at a high spin rate, hence generating a well-defined hydrodynamic steady-state convection layer at the underlying stationary electrode. The features afforded by this new kinetic method were investigated for three different reaction schemes: (i) the chemical oxidative deprotection of a boronic ester by H2O2, (ii) a biomolecular binding recognition between a small target and an aptamer, and (iii) the inhibition of the redox-mediated catalytic cycle of horseradish peroxidase (HRP) by its substrate H2O2. For the small target/aptamer binding reaction, the kinetic and thermodynamic parameters were recovered from rational analysis of the kinetic plots, whereas for the HRP catalytic/inhibition reaction, the experimental amperometric kinetic plots were reproduced from numerical simulations. From the best fits of simulations to the experimental data, the kinetics rate constants primarily associated with the inactivation/reactivation pathways of the enzyme were retrieved. The ability to perform kinetics in microliter-size samples makes this methodology particularly attractive for reactions involving low-abundance or expensive reagents.
