A suspension of N′-(4-iodobenzoyl)-4-[4-(4-methylcyclohexyl)-1-piperazinyl]benzohydrazide (22.95 g) in pyridine (459 ml) was treated with phosphorus pentasulfide (11.2 g) and stirred at 120° C. for 2.5 hours. The reaction mixture was added a solution of sodium hydroxide (510 g) in water (9200 ml). The resulting precipitate was collected, washed with acetone. The powder was recrystallized from THF (800 ml) and dried to give 1-[4-[5-(4-iodophenyl)-1,3,4-thiadiazol-2-yl]phenyl]-4-(4-methylcyclohexyl)piperazine (16.42 g).
