STUDY OF THE RING-CLOSURE REACTION OF O-AMINOARYLSULFONAMIDES WITH 1,1'-THIOCARBONYLDIIMIDAZOLE

1,1'-Thiocarbonyldiimidazole was used as a ring closure agent for o-am inoarylsulfonamides. Beside the formation of the expected 3-thioxo-2,3 -dihydro-4H-1,2,4-arylthiadiazine 1,1-dioxide derivatives, a new kind of compound was also obtained namely the 3-(imidazol-1-yl)-4H-1,2,4-ar ylthiadiazine 1,1-dioxides. The latter appeared to be good reaction in termediates. The use of 1,1'-thiocarbonyldiimidazole opens a new synth etic route to 3-alkylamino-4H-1,2,4-arylthiadiazine 1,1-dioxides, a he terocyclic ring system expressing important pharmacological properties . This work is the first study on the ring closure properties of this reagent. (C) 1998 Elsevier Science Ltd. All rights reserved.