Photorelease of Pyridines Using a Metal‐Free Photoremovable Protecting Group. (20th August 2020)

• Record Type: Journal Article
• Authors: Tang, Xiao‐Jun; Wu, Yayun; Zhao, Rong; Kou, Xiaolong; Dong, Zaizai; Zhou, Wei; Zhang, Zhen; Tan, Weihong; Fang, Xiaohong
• Is Part Of: Angewandte Chemie. Volume 132:Number 42(2020)
• Page Start: 18544
• Page End: 18547
• Publication Date: 2020-08-20
• Subjects: dyes/pigments -- photochemistry -- photolysis -- pyridine -- two-photon activation; Chemistry -- Periodicals; 540
• DOI: 10.1002/ange.202005310
• Languages: English
• ISSNs: 0044-8249

Abstract

Abstract: The photorelease of bioactive molecules has emerged as a valuable tool in biochemistry. Nevertheless, many important bioactive molecules, such as pyridine derivatives, cannot benefit from currently available organic photoremovable protecting groups (PPGs). We found that the inefficient photorelease of pyridines is attributed to intramolecular photoinduced electron transfer (PET) from PPGs to pyridinium ions. To alleviate PET, we rationally designed a strategy to drive the excited state of PPG from S1 to T1 with a heavy atom, and synthesized a new PPG by substitution of the H atom at the 3‐position of 7‐dietheylamino‐coumarin‐4‐methyl (DEACM ) with Br or I. This resulted in an improved photolytic efficiency of the pyridinium ion by hundreds‐fold in aqueous solution. The PPG can be applied to various pyridine derivatives. The successful photorelease of a microtubule inhibitor, indibulin, in living cells was demonstrated for the potential application of this strategy in biochemical research. Abstract : Photorelease of pyridines from their corresponding pyridinium ions in aqueous solution is difficult due to efficient photoinduced electron transfer (PET) from photoremovable protecting groups (PPGs) to the pyridinium. Driving the excited state of coumarin‐based PPG from S1 to T1 by introducing a heavy atom alleviates PET and enhances photolytic efficiency by hundreds‐fold.