Original Article:
Ca(IO3)2 nanoparticles: fabrication and application as an eco-friendly and recyclable catalyst for the green synthesis of quinoxalines, pyridopyrazines, and 2,3-dicyano pyrazines
Mehdi Kalhor, et al.
Research on Chemical Intermediates, 2023, 49, 885-900.
10.1007/s11164-022-04914-3
Iodates are a class of compounds containing IO3- groups. Among them, calcium iodate (Ca(IO3)2) is mainly used as deodorant, medicine and food additive. Here, the researchers explored the potential of calcium iodate as an inexpensive, safe, stable, and recyclable catalyst for the facile synthesis of heterocyclic compounds, including quinoxalines, 5,6-dicyano pyrazines, and pyrido[2,3-b] pyrazines. The results show that calcium iodate catalysis increases the yield and shortens the reaction time, which is benefited from the presence of calcium ions as a strong Lewis acid and the strong oxidation of iodate ions.
The reaction process of calcium iodate as a catalyst in the one-pot condensation synthesis of heterocyclic compounds is shown in the figure.
1. Calcium ion first activates the carbonyl group of 1,2-diketone as a Lewis acid to form intermediate (A), following the nucleophilic attack of the amine group.
2. Schiff base (B) is then generated through the catalytic oxidation and removal of a water molecule.
3. Finally, the intramolecular nucleophilic attack of the second amine substituent and the oxidative elimination of the second water molecule yield quinoxaline, pyrido[2,3-b]pyrazine, and 3,4-dicyanopyrazine heterocycle rings (3a–q) through the catalytic activation of the imine carbon.
Chemicals Related in the Paper:
| Catalog Number | Product Name | Structure | CAS Number | Price |
|---|---|---|---|---|
| ACM10031320 | CALCIUM IODATE |  |
10031-32-0 | Price |
| ACM15454316 | iodate |  |
15454-31-6 | Price |
