1
|
Liu Y, Luo Q, Qiang Q, Wang H, Ding Y, Wang C, Xiao J, Li C, Zhang T. Successive Cleavage and Reconstruction of Lignin β-O-4 Models and Polymer to Access Quinoxalines. CHEMSUSCHEM 2022; 15:e202201401. [PMID: 36055966 DOI: 10.1002/cssc.202201401] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/22/2022] [Revised: 08/31/2022] [Indexed: 06/15/2023]
Abstract
The construction of N-heterocyclic compounds from lignin remains a great challenge due to the complex lignin structure and the involvement of multiple steps, including the cleavage of lignin C-O linkages and the formation of heterocyclic aromatic rings. Herein, the first example of KOH mediated sustainable synthesis of quinoxaline derivatives from lignin β-O-4 model compounds in a one-pot fashion under transition-metal-free conditions has been achieved. Mechanistic studies suggested that this transformation includes highly coupled cascade steps of cleavage of C-O bonds, dehydrative condensation, sp3 C-H bond oxidative activation, and intramolecular dehydrative coupling reaction. With this protocol, a wide range of functionalized quinoxalines, including an important drug compound AG1295, were synthesized from lignin β-O-4 model compounds and β-O-4 polymer, showcasing the application potential of lignin in pharmaceutical synthesis.
Collapse
Affiliation(s)
- Yuxuan Liu
- CAS Key Laboratory of Science and Technology on Applied Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 116023, Dalian, P. R. China
| | - Qi Luo
- CAS Key Laboratory of Science and Technology on Applied Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 116023, Dalian, P. R. China
| | - Qian Qiang
- CAS Key Laboratory of Science and Technology on Applied Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 116023, Dalian, P. R. China
- University of Chinese Academy of Sciences, 100049, Beijing, P. R. China
| | - Hua Wang
- CAS Key Laboratory of Science and Technology on Applied Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 116023, Dalian, P. R. China
| | - Yangming Ding
- CAS Key Laboratory of Science and Technology on Applied Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 116023, Dalian, P. R. China
| | - Chao Wang
- School of Chemistry and Chemical Engineering, Key Laboratory of Applied Surface and Colloid Chemistry, Ministry of Education, Shaanxi Normal University, 710119, Xi'an, P. R. China
| | - Jianliang Xiao
- Department of Chemistry, University of Liverpool, L69 7ZD, Liverpool, United Kingdom
| | - Changzhi Li
- CAS Key Laboratory of Science and Technology on Applied Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 116023, Dalian, P. R. China
- University of Chinese Academy of Sciences, 100049, Beijing, P. R. China
| | - Tao Zhang
- CAS Key Laboratory of Science and Technology on Applied Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 116023, Dalian, P. R. China
- University of Chinese Academy of Sciences, 100049, Beijing, P. R. China
| |
Collapse
|