Weidener, Dennis; Singh, Kawarpal; Bluemich, Bernhard published the artcile< Synthesis of α-fluoro-α,β-unsaturated esters monitored by 1D and 2D benchtop NMR spectroscopy>, SDS of cas: 94-02-0, the main research area is fluoropropenoate preparation activation energy deprotonation deacylation kinetics mechanism; compact NMR spectrometer; deacylation; deprotonation; flow NMR; reaction monitoring.
For optimization and control of pharmaceutically and industrially important reactions, chem. information is required in real time. Instrument size, handling, and operation costs are important criteria to be considered when choosing a suitable anal. method apart from sensitivity and resolution This present study explores the use of a robust and compact NMR spectrometer to monitor the stereo-selective formation of α-fluoro-α,β-unsaturated esters from α-fluoro-β-keto esters via deprotonation and deacylation in real time. These compounds are precursors of various pharmaceutically active substances. The real-time study revealed the deprotonation and deacylation steps of the reaction. The reaction was studied at temperatures ranging from 293 to 333 K by interleaved one-dimensional 1H and 19F and two-dimensional 1H-1H COSY experiments The kinetic rate constants were evaluated using a pseudo first-order kinetic model. The activation energies for the deprotonation and deacylation steps were determined to 28 ± 2 and 63.5 ± 8 kJ/mol, resp. This showed that the deprotonation step is fast compared with the deacylation step and that the deacylation step determines the rate of the overall reaction. The reaction was repeated three times at 293 K to monitor the repeatability and stability of the system. The compact NMR spectrometer provided detailed information on the mechanism and kinetics of the reaction, which is essential for optimizing the synthetic routes for stepwise syntheses of pharmaceutically active substances.
Magnetic Resonance in Chemistry published new progress about Activation energy. 94-02-0 belongs to class esters-buliding-blocks, and the molecular formula is C11H12O3, SDS of cas: 94-02-0.
Referemce:
Ester – Wikipedia,
Ester – an overview | ScienceDirect Topics