Avobenzone is a dibenzoylmethane compound commonly found in sunscreens and can photoisomerize after exposure to near-ultraviolet light. At equilibrium, Avobenzone exists as a chelated enol characterized by a strong intramolecular hydrogen bond. The photochemistry of Avobenzone includes keto-enol tautomerization, cis-trans isomerization, rotation about the single bond and α bond cleavages of carbonyl groups. Findings suggest that torsion around the double C2-C3 bond of photoexcited chelated enol leads to internal conversion to the ground state and formation of rotamer E. In addition, opening of the chelated hydrogen ring by torsion of the hydroxyl group creates non-chelated enol. The possible mechanisms of rotamer Z formation are discussed.
Sun, Dong-Wei; Jiang, Min; Liu, Jin-Tao. Novel Bifunctionalization of Activated Methylene: Base-Promoted Trifluoromethylthiolation of β-Diketones with Trifluoromethanesulfinyl Chloride. Chemistry - A European Journal. Key Laboratory of Organofluorine Chemistry, Shanghai Institute of, Organic Chemistry. University of Chinese Academy of Science, Chinese Academy of Science. Shanghai, Peop. Rep. China 200032. Volume 25. Issue 46. Pages 10797-10802. 2019
Cheng, Jianhua; Wang, Xiaojun; Wu, Chongcai; Wan, Jianxin. Preparation technology of sunscreen agent Parsol 1789.Xiangliao Xiangjing Huazhuangpin. Chemical Engineer School. The South China University of Technology. Zhanjiang, Peop. Rep. China 510641. Issue 3. Pages 8-10. 2002.
Li, Min; Wei, Dan; Liu, Zhi-xiong. Synthesis of tert - butyl - methoxy - dibenzoylmethane under microwave irradiation. Riyong Huaxue Gongye. Department of Pharmacy. Guangdong Pharmaceutical University. Guangdong, Peop. Rep. China 510006. Volume 39. Issue 3. Pages 179-182. 2009
Miralles, Ricardo; Nonell, Santiago; Raga, Manuel M.; Giuglietta, Antonio.Industrial preparation of benzoic acid ester derivatives for use as sunscreen lotions and cosmetics. Assignee Ferrer Internacional, S. A., Spain; Teixido, Jordi. WO 2006100225. 2006
Habeck, Thorsten; Prechtl, Frank. Preparation of dibenzoylmethanes. Assignee Basf Aktiengesellschaft, Germany. EP 994092. 2000
Koide, Masashi; Ishii, Hiroshi. Pressure-sensitive adhesive compositions containing polyesters and diphenyldiketones with excellent UV-shielding properties and optical laminates and organic electroluminescent cells using them. Assignee Toyo Ink Mfg. Co., Ltd., Japan. JP 2008297478. 2008
Frater, Georg; Huber, Ulrich. Process for the purification of 1,3-diketones. Assignee Roche Vitamins A.-G., Switz. WO 2002062738. 2002
Liu, Zhongchun. A method for synthesis of avobenzone. Assignee Jiangxi Hengtong Technology Development Co., Ltd., Peop. Rep. China. CN 104876814. 2015
Liu, Qifa; Wang, Rong; Yang, Jian. Preparation of ultraviolet absorbent avobenzone. Assignee Suqian Cosmos Chemical Co., Ltd., Peop. Rep. China. CN 108658741. 2018
Wang, Min. Method for synthesizing avobenzone. CN 109867597. 2019
