Recent developments in the chemistry and enzyme inhibitory activity of fused thiazoles and thiadiazoles

Abstract The combination of cyclization reactions of thiadiazoles and benzothiazoles with Pd‐catalyzed cross‐coupling reactions provided a convenient synthesis of annulated, fluorinated and non‐fluorinated heterocycles, such as 1,3,4‐thiadiazolo[3,2‐ a ]pyrimidin‐5‐ones, benzothiazolo[3,2‐ a ]pyridimidin‐4‐ones, benzothiazolo[2,3‐ b ]quinazolin‐12‐ones and thiadiazolo[2′,3′:2,3]‐imidazo[4,5‐ b ]indoles. The inhibitory activity of the products against nucleotide pyrophosphatases (NPPs), alkaline phosphatases (APs), ectonucleoside triphosphate diphosphohydrolases (NTPDs), cervical cancer cells (HeLa), and monoamine oxidases (MAO) was studied experimentally and further elucidated by docking studies. As a result, several heterocycles were identified as privileged core structures, and compounds of each series were identified as lead structures for further investigations.