A novel and efficient synthesis of imidazo[1,5-a]pyradines

• Main Author: Mason, Richard J., Jr.
• Format: Others
• Published: DigitalCommons@Robert W. Woodruff Library, Atlanta University Center 2007
• Subjects: Chemistry
• Online Access: http://digitalcommons.auctr.edu/dissertations/3047; http://digitalcommons.auctr.edu/cgi/viewcontent.cgi?article=4017&context=dissertations

A one-pot and straightforward synthesis, which results in the formation of imidazo[1,5-a]pyridines, has been intensely investigated. This methodology has been applied to 2,2'-pyridil, α- pyridoin and 2-benzoylpyridne ketone systems respectively. Treatment of 2,2'-pyridiI, α -pyridoin or 2-benzoylpyridine with aromatic aldehydes, and ammonium acetate in the presence of hot acetic acid has been shown to give 1-(2-Pyridoyl)-3-phenylimidazolesand 1,3-di-phenylimidazo[1,5-a]pyridines in good to excellent yields. These reactions were carried out without the use of metal catalysts, which is a commonly used methodology for imidazo[1,5-a]pyridine synthesis. A new and efficient synthesis of 1,3-diaryl-[1,5-a]imidazopyridines has also been developed based on the reaction of 2-benzoylpyiridne with aldehydes in the presence of ammonium acetate and hot acetic acid Aldehydes applicable to this reaction include aryl aldehydes, heteroaromatic aldehydes, salicylaldehydes.