Photosensitized single electron transfer oxidation of N-hydroxylamines: A convenient synthesis of cyclic nitrones

Polyphosphoric acid-promoted one-pot synthesis and neuroprotective effects of flavanones against NMDA-induced injury in PC12 cells

We report herein an efficient polyphosphoric acid (PPA) promoted one-pot protocol for the synthesis of flavanone derivatives from 2-hydroxyacetophenones and benzaldehydes. A variety of flavanones were produced in moderate to excellent yields and evaluated for their neuroprotective effects against N-methyl-d-aspartate (NMDA)-induced excitotoxicity in PC12 cells. Derivatives bearing electron-donating groups exhibited better neuroprotective activity. Compound 3m demonstrated the best protective potency and reversed the intracellular calcium (Ca²⁺) influx caused by NMDA, suggesting that flavanones protected the PC12 cells against NMDA-induced neurotoxicity via inhibition of Ca²⁺ overload.

The photophysics of photoredox catalysis: a roadmap for catalyst design

The photophysical properties of transition metal-based charge-transfer chromophores are discussed with an eye toward their application in organic photoredox catalysis.

Synthesis of Nitrones Using the Methyltrioxorhenium/Hydrogen Peroxide System

Secondary amines are oxidized by the methyltrioxorhenium/hydrogen peroxide system to the corresponding nitrones in excellent yield. The results provide a further example of the parallel between the chemistry of this metal system and that of the dioxiranes.