Synthesis of novel herbicidal sulfonylureas

Novel sulfonylurea derivatives containing five-membered heterocycle 3a-1 an d 4a-d were synthesized in good yields by the regioselective addition of ar yl sulfonylisocyanates 1 to 5-amino-9-benzyl (aryl) thio-1, 2, 4-triazoles and its pyrazole analogues 2. The structures of all these compounds were ev aluated by elemental analyses and H-1 MMR spectroscopy. The preliminary bio logical tests showed that the products displayed herbicidal activity agains t rape to some extent.