a compound of formula i or an intermediate compound for pharmacological and therapeutic use the compounds of formula i or formula xx may be used or administered in the free base form or as a physiologically acceptable acid addition salt the preparation and use of such salts is well known in the art examples of appropriate salts are those formed from the following inorganic and organic acids hydrochloric hydrobromic sulfonic sulfuric phosphoric nitric maleic fumaric benzoic ascorbic pamoic succinic methanesulfonic acetic propionic tartaric citric lactic malic madelic cinamic palmitic itaconic and benzenesulfonic the invention includes all such acid addition salts of the compounds of formula i or formula xx the physiologically acceptable acid addition salts are preferred the antihypertensive effect of a compound of formula i is elicited and demonstrated by administering the compound to a hypertensive rat and measuring the change in systolic blood pressures from just prior to drug administration to 1 5 4 and 24 hours thereafter the systolic blood pressure of male conscious spontaneously hypertensive rat shr taconic farms is measured by indirect tail plethysmography using a system designed and built by narco bio systems model mk iv groups consisting of 4 rats receive a single oral dose of the test compound rats are warmed in a heated chamber at 38 u00b0 c for 10 minutes prior to measurement of systolic pressure to increase the accuracy of measurements the systolic pressure and heart rate data are collected in an.