Cyclic sulfamides are attractive molecules with potential application in medical chemistry. It is known that thiadiazepine-containing derivatives demonstrate promising value in the development of protease inhibitors such as HIV protease, serine protease and metaloprotease. We demonstrate here a comfortable synthetic sequence to symmetric thiadiazepines containing isoxazole substitutents. The structure of the obtained substances was confirmed by 1H, 13C NMR spectroscopy.