Ayesha Nisathar Graduate Student, Department of Chemistry University of Georgia Learn more about the speaker Thursday, December 2, 2021 - 11:10am Chemistry Building, Room 400 Organic Seminar Isomeric ortho- and para-quinone methides, while possessing similar electronic structures, show very different properties. o-Quinone methides (oQM) are more reactive towards nucleophiles and undergo very fast and efficient inverse electron-demand-Diels-Alder (IEDDA) reaction with electron-rich alkenes. p-Quinone methide, while also acting as Michael acceptors, is not reactive in IEDDA. The photochemical generation of o-naphthoquinone methide (o-NQM) from (3-hydroxynaphthalen-2-yl)methanol (o-NQMP) derivatives can be achieved with UV-A light This reaction has been employed for the development of photolabile protecting groups (PPGs), procedure for the protein and peptide labeling, as well as reversible surface derivatization. In the present project, (3-hydroxynaphthalen-2-yl)(4-hydroxyphenyl)methanol (QMP 1) was designed to explore the feasibility of a novel approach to the generation of a fluorescent dye. Interestingly, photo-dehydration of QMP 1 can produce both tautomers: o-naphthoquinone methide (o-NQM 1) and p-quinone methide (p-QM 1). Thus, the photoreactivity study of QMP 1 was carried to find out the predominant form of QM. Comparative analysis of the kinetics of QMP 1 reactions versus two structural analogs QMP 2, and QMP 3 will be presented. Photo-dehydration of QMP 2 can only form o-naphthoquinone methide analog (o-NQM 2), while QMP 3 is expected to produce only p-quinone methide analog (p-QM 3). Furthermore, applications of QMP analogs as fluorophores for imaging techniques will be provided. References Bai, W.J.; David, J. G.; Feng, Z. G.; Weaver, M. G.; Wu, K. L.; Pettus, T. R. R. The domestication of ortho-quinone methides. Acc. Chem. Res. 2014, 47, 3655-3664 Nachtsheim, B. J. Mild map to quinone methide. Nat. chem. 2020, 12, 326-328 Arumugam, S.; Popik, V. V. Photochemical generation and the reactivity of o-naphthoquinone methides in aqueous solution. J. Am. Chem. Soc. 2009, 131, 11892-11899 Kulikov, A.; Arumugam, S.; Popik, V. V. Photolabile protection of alcohols, phenols, and carboxylic acids with 3-hydroxy-2nanphathalenemethanol. J. Org. Chem. 2008, 73, 7611-7615 Padwa, A.; Dehm, D.; Oine, T.; Lee, G. A. Competitive keto-enolate photochemistry in the 3-phenylisocoumaranone system. J. Am. Chem. Soc. 1975, 97, 1837-1845 Dempsey, G. T.; Vaughan, J. C.; Chen, K. H.; Bates, M.; Zhuang, X. Evaluation of fluorophores for optimal performance in localization-based super-resolution imaging. Nature methods 2011, 8, 1027-1036
