A convenient one‐pot synthesis and antimicrobial activity of pyrimido[1,2‐b][1,2,4,5]tetrazines

The synthesis of the hitherto unreported 3‐amino‐2,3‐dihydro‐6‐phenyl‐2‐thioxo‐4(1H)‐pyrimidine 2 and 3‐amino‐2‐methylthio‐6‐phenyl‐4(3H)‐pyrimidinone 3 is described. Reactions of hydrazonoyl halides 1 with either 2 or 3 afforded 6H‐pyrimido1,2‐b]1,2,4,5]tetrazin‐6‐ones 6. The latter products were screened for their antifungal and antibacterial properties. The mechanism of the studied reactions is discussed.