Alessandro Manfrin published a paper in The Journal of Organic Chemistry on the singlet oxygen reactivity of oxazoles and thiazoles included in peptidic chains. Oxazoles and thiazoles are five-membered aromatic rings, found in natural peptides, and known to undergo rapid oxidation in the presence of singlet oxygen. In this work we synthesized model oxazole- and thiazole-peptides and demonstate that their singlet oxygen reactivity dramatically changes when they are included in peptidic chains. Experimentally and computationally we proved this effect to be ascribed to the ring substituent, we elucidate singlet oxygen reaction products and provide reaction rate constants of model peptides and of the RiPP Aerucyclamide A. Overall we propose model peptides to study the reactivity of larger natural peptides, and proved the stability of these systems in peptides produced by sunlight-dwelling organisms.
Singlet Oxygen Photooxidation of Peptidic Oxazoles and Thiazoles
Alessandro Manfrin, Nadine Borduas-Dedekind, Kate Lau, and Kristopher McNeill*
J. Org. Chem. 2019 https://pubs.acs.org/doi/abs/10.1021/acs.joc.8b02684