Research on Thermal Decomposition Kinetics and Thermal Safety for a New Epoxiconazole Crystal

To clarify the thermal safety inherent in a new epoxiconazole crystal, differential scanning calorimetry (DSC) and adiabatic accelerating rate calorimetry (ARC) were used for testing and research. The Friedman method and model method were used to analyze thermal decomposition kinetics based on the DSC data, and the N-order and autocatalytic decomposition reaction kinetic models were established. The double scan method was utilized to verify the autocatalytic effect during the decomposition process. The Friedman method, N-order, and autocatalytic model methods were used to study the substance's thermal decomposition characteristics. ARC data are utilized to verify the aforementioned prediction results and the kinetic parameters that were obtained based on ARC data from N-order and autocatalytic model methods that concur with the simulation results. This paper applies the N-order and autocatalytic model to the kinetic model to further predict thermal safety parameter time to maximum rate under adiabatic conditions.

Stereoselective synthesis of monomeric flavonoids

Polyphenolic compounds have recently attracted considerable interest in the field of nutrition, health and medicine. This is the result of the growing body of evidence suggesting that these compounds may act as potent antioxidants and/or modulate key biological pathways in vivo in mammals. Studies aimed at comprehending the intricate principles that govern the chemistry of these important natural products have thus accelerated over the past decade. Prominent amongst these is the ability to synthesize monomeric prototypes with and without 13C- and radio-labeling. Endeavors exploiting the stereoselective syntheses of representative classes of flavonoid monomers are reviewed here.

Highly enantioselective epoxidation of styrenes: implication of an electronic effect on the competition between spiro and planar transition states

Asymmetric epoxidation of various styrenes using carbocyclic oxazolidinone-containing ketone 3 has been investigated. High enantioselectivity (89-93% enantiomeric excess) has been attained for this challenging class of alkenes. Mechanistic studies show that substituents on the ketone catalyst can have electronic influences on secondary orbital interactions, which affects the competition between spiro and planar transition states and, ultimately, enantioselectivity. The results described herein not only reveal the potential of chiral dioxirane catalyzed asymmetric epoxidation as a viable entry into this important class of olefins but also further enhance the understanding of the mechanistic aspects of chiral ketone-catalyzed asymmetric epoxidation.