Synthesis
General procedure for the synthesis of 2-(imidazol-2-yl)pyridine from 2-(4,5-dihydro-1H-imidazol-2-yl)pyridine: a generalized method of [Mn(TPP)Cl]-catalyzed dehydrogenation of imidazolines with NaIO4 was used. All reactions were carried out at room temperature and air atmosphere in a 25 mL round bottom flask equipped with a magnetic stir bar. To a solution of CH3CN (5 mL) containing 2-imidazoline (1 mmol) and [Mn(TPP)Cl] (0.05 mmol), a solution of NaIO4 (2 mmol) in H2O (10 mL) was added. The reaction process was monitored by thin layer chromatography (TLC) (eluent: EtOAc/MeOH, 4:1). After completion of the reaction, water (30 mL) was added and the target product imidazole was extracted with CH2Cl2 (2 x 20 mL). After evaporation of the solvent, the imidazole derivative was obtained. The structure of the product was confirmed by infrared spectroscopy (IR) and 1H nuclear magnetic resonance (1H NMR) data.
References
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[2] Transition Metal Chemistry, 2013, vol. 38, # 1, p. 1 - 5
[3] Canadian Journal of Chemistry, 2005, vol. 83, # 2, p. 110 - 114
[4] Tetrahedron Letters, 2004, vol. 45, # 47, p. 8687 - 8690
[5] Polyhedron, 2011, vol. 30, # 9, p. 1463 - 1468
