NMR spectroscopic structure elucidation of the products of the reaction of 3-(3-aryl-3-oxopropenyl)- chromen-4-ones with 1,2-phenylenediamine.

The reaction of 3-(3-aryl-3-oxopropenyl)chromen-4-ones with 1,2-phenylenediamine resulted in the unexpected formation of 10a-aryl-1,2,10,10a-tetrahydrobenzo-[4,5]-imidazo[1,2-a]pyridin-3-yl(2-hydroxyphenyl)-1-methanones. Their structure elucidation and complete 1H and 13C assignments have been performed by a combination of various one- and two-dimensional NMR experiments.