“…Research Department, Abbott Laboratories Ltd., Montreal, Quebec, Canada Received January 7,1969 In these laboratories, for a number of years, we have been interested in piperazine derivatives as antihypertensive agents. This report presents the syntheses of several 1-alkyl-(or 1-arylor 1-aralkyl-) 4-N-substituted carbamoyl-(or thiocarbamoyl-, ureido-, or thioureido-) piperazines and the evaluation of their biological activities.…”