The reactions of symmetrical and unsymmetrical 2,2′-dipyridylamines with 1,2-dibromoethane and 1,3-dibromopropane give imidazopyridinium and pyridopyrimidium bromides, respectively. These acetone/CH2Cl2 -insoluble, highly fluorescent quaternary ammonium salts undergo addition/ring opening upon treatment with methanolic KOH to give pyridin-2-one derivatives. A sequential N,N-dialkylation/ring-opening hydrolysis/N,N-dialkylation/ring-opening hydrolysis strategy was developed for the construction of unsymmetrical bis(pyridin-2-ones).
ASJC Scopus subject areas
- Organic Chemistry