An atomically dispersed Co catalyst for efficient oxidative fabrication of benzoheterocycles under ambient oxygen conditions

• Published in: Green chemistry : an international journal and green chemistry resource : GC 2024-04, Vol.26 (8), p.4834-4843
• Main Authors: Chen, Jia-Yue, Li, Ke-Ming, Sun, Yu-Xuan, Xiao, Yao, Guo, Feng-Shuo, Huang, Yao-Bing, Lu, Qiang
• Format: Article
• Language: English
• Subjects: Benzimidazoles; Benzothiazole; Catalysis; Catalysts; Dehydrogenation; Fabrication; Heterocyclic compounds; Intermediates; Metal-organic frameworks; Oxidation; Oxidation resistance; Oxygen; Poisoning (reaction inhibition); Pyrolysis; Sulfur; Sulphur; Synthesis; Zeolites
• ISSN: 1463-9262; 1463-9270
• DOI: 10.1039/d4gc00445k

The highly efficient synthesis of benzoxazole, benzothiazole and benzimidazole has attracted much attention due to their superior biological activities. However, developing environmentally friendly and poisoning-resistant catalysts in heterogeneous catalytic systems remains a critical challenge. Herein, an atomically dispersed Co 1 /NC catalyst was fabricated by facile pyrolysis of a zeolitic imidazolate framework (ZnCo-ZIF). The Co 1 /NC catalyst exhibited excellent oxidation catalysis, sulfur-resistance and reusability performance. The mass specific activity (MSA) of Co 1 /NC was up to 42.0 mol 2-PBO mol Co −1 h −1 , much higher than that of the Co/NC nano-catalyst (15.6 mol 2-PBO mol Co −1 h −1 ). Mechanism studies showed that O 2 was activated by atomically dispersed Co active species to form 1 O 2 and &z.rad;O 2 − , which were responsible for the dehydrogenation of the key imine intermediates to produce 2-phenylbenzoxazole (2-PBO). The current work represents a novel feasible strategy for the synthesis of bioactive heterocyclic compounds using efficient, stable and green heterogeneous catalysts. The first Co 1 /NC SAC is reported to produce benzoheterocycles under oxygen conditions, and the yields of 2-PBO, 2-PBT and 2-PBM were 99%, 95% and 99%, respectively.