Abstract
Hypocrellin A (HA), a hydroxylperylenequinone derivative, is an efficient phototherapeutic agent. The reactivity of the semiquinone radical anion of HA (HA −) with O 2 in aprotic medium has been studied. Although the standard redox potential of the HA −HA couple (−360 mV vs. a normal hydrogen electrode (NHE)) is less negative than that of the O 2 −O 2 couple (−500 mV vs. NHE), it appears that HA − can still be oxidized with oxygen. The electron transfer is accompanied by a proton transfer between one of the phenolic hydroxyl groups of HA and O 2 − yielding the conjugated base of HA (HA b −) and hydrogen peroxide. On the basis of the results obtained from spectrophotometric, electron spin resonance spin-trapping and CCl 4-inhibiting experiments, a reasonable reaction pathway was proposed for the oxidation of HA − with O 2 in aprotic media.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callMore From: Journal of Photochemistry & Photobiology, A: Chemistry
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
