Water-Involved Ring-Opening of 4-Phenyl-1,2,4-triazoline-3,5-dione for "Photo-Clicked" Access to Carbamoyl Formazan Photoswitches In Situ.

Yuanqin Zheng, Yuqiao Zhou, Yan Zhang, Pengchi Deng, Xiaohu Zhao, Shichao Jiang, Guangxi Du, Xin Shen, Xinyu Xie, Zhishan Su, Zhipeng Yu

Chemistry, an Asian journal 2022 Jan 17

filter terms:

Cyclic azodicarbonyl derivatives, particularly 4-phenyl-1,2,4-triazoline-3,5-dione (PTAD), commonly serve as arenophile, dienophile, enophile and electrophile. Perplexed by its instability in aqueous environment, there are few studies focused on the transient intermediate produced by hydrolysis of PTAD to achieve synthetic significance. Herein, we describe a "photo-click" method that involves nitrile imine (NI) from diarylsydnone to capture the diazenecarbonyl-phenyl-carbamic acid (DACPA) generated by water-promoted ring-opening of PTAD. DFT calculation reveal that H-bonding interactions between PTAD and water are vital to form DACPA which exhibited an umpolung effect during ligation by nature bond orbit (NBO) analysis. The ultra-fast ligation resulted in carbamoyl formazans, as a unique Z↔E photo-switchable linker on target molecules, including peptide and drugs, with excellent anti-fatigue performance. This strategy is showcased to construct highly functionalized carbamoyl formazans in situ for photo-pharmacology and material studies, which also expands the chemistry of PTAD in aqueous media. © 2021 Wiley-VCH GmbH.

Citation

Yuanqin Zheng, Yuqiao Zhou, Yan Zhang, Pengchi Deng, Xiaohu Zhao, Shichao Jiang, Guangxi Du, Xin Shen, Xinyu Xie, Zhishan Su, Zhipeng Yu. Water-Involved Ring-Opening of 4-Phenyl-1,2,4-triazoline-3,5-dione for "Photo-Clicked" Access to Carbamoyl Formazan Photoswitches In Situ. Chemistry, an Asian journal. 2022 Jan 17;17(2):e202101239