A new convenient synthetic approach to diarylpyrimidines

A new synthetic method in pyrimidine chemistry has been developed. 2,2,2-Trichloroethylideneacetophenones, easily available from chloral and acetophenones, reacted with benzamidines to provide novel 2,6-diaryl-6-hydroxy-4-trichloromethyl-1,4,5,6-tetrahydropyrimidines in near quantitative yields. Efficient dehydration of these compounds gave previously unknown 2,4-diaryl-6-trichloromethyl-1,6-dihydropyrimidines, which were found able to undergo base-induced chloroform elimination to give 2,4-diarylpyrimidines in high yields. Molecular structures for final and intermediate compounds were determined by single crystal X-ray diffraction. A main improvement of this procedure lies in circumventing the oxidative aromatization of dihydropyrimidine intermediates through a chloroform elimination process. The diarylpyrimidines were also found directly accessible by a fair yield one-pot procedure. [Display omitted]