Visible light-induced recyclable g-C3N4 catalyzed thiocyanation of C(sp(2))-H bonds in sustainable solvents

• Published in: Green chemistry : an international journal and green chemistry resource : GC Vol. 23; no. 10; pp. 3677 - 3682
• Main Authors: Zeng, Fan-Lin, Zhu, Hu-Lin, Chen, Xiao-Lan, Qu, Ling-Bo, Yu, Bing
• Format: Journal Article
• Language: English
• Published: CAMBRIDGE Royal Soc Chemistry 01.01.2021; Royal Society of Chemistry
• Subjects: air; Carbon nitride; carbonates; Catalysts; Chemistry; Chemistry, Multidisciplinary; Green & Sustainable Science & Technology; Green chemistry; Irradiation; Light effects; Organic solvents; Oxidants; Oxidizing agents; photocatalysis; Physical Sciences; Pyridines; Science & Technology; Science & Technology - Other Topics; Solvents; volatile organic compounds
• ISSN: 1463-9262; 1463-9270; 1463-9270
• DOI: 10.1039/d1gc00938a

A metal-free photocatalytic strategy for the preparation of thiocyanated heterocycles from inexpensive NH4SCN has been developed using carbon nitride (g-C3N4) as a general heterogeneous catalyst in a green solvent under an air atmosphere and the irradiation of a blue LED. Various thiocyanated heterocycles including indolo[2,1-a]isoquinolin-6(5H)-ones, benzimidazo[2,1-a]isoquinolin-6(5H)-ones, thioflavones, azaspiro[4.5]trienones and imidazo[1,2-a]pyridines were successfully synthesized in good yields (up to 96%). Importantly, this metal-free and external-oxidant-free procedure employed dimethyl carbonate as a green medium, avoiding the traditional volatile organic solvents. Moreover, the recyclable g-C3N4 catalyst could be used at least 8 times without significant loss of activities.