Preparation of nucleoside–pyridine hybrids and pyridine attached acylureas from an unexpected uracil ring-opening and pyridine ring-forming sequence

Novel pyrimidine nucleoside-3,5-dicyanopyridine hybrids ( 4) or pyridine attached acylureas ( 5) were selectively and efficiently prepared from the reaction of 2′-deoxyuridin-5-yl-methylene malononitrile ( 1), malononitrile ( 2) and thiophenol ( 3) or from an unexpected uracil ring-opening and pyridine ring-forming sequence via the reaction of 1 and 3. It is the first time such a sequence has ever been reported.