1. Haugland, M. M.; Anderson, E. A.; Lovett, J. E. Electron Paramagn. Reson. 2017, 25, 1.
2. (a) Rule, N. G.; Kung, T.-M. US Patent 5039585. (b) Lenhard, J. R.; Shukla, D. US Patent 7471437.
3. (a) Rentner, J.; Kljajic, M.; Offner, L.; Breinbauer, R. Tetrahedron 2014, 70, 8983. (b) Ward, D. E. Chem. Commun. 2011, 47, 11375. (c) Becerril-Jiménez, F.; Ward, D. E. Org. Lett. 2012, 14, 1648.
4. Zhang, K. Oncol. Lett. 2016, 11, 4160. (b) Lei, F.
5. Zhu, W. Eur. J. Med. Chem. 2016, 116, 27. (c) Hegab, M. I.