Structure-activity studies were carried out on a series of antihypertensive 1-(2-aminoethyl)-3-(substituted phenyl)thioureas. From this class of compounds, the 2,6-dichlorophenyl analogue 2 was found to have potent oral antihypertensive activity in two hypertensive rat models and the renal hypertensive dog. In addition to its effect on blood pressure, 2 displayed sedative effects which had a marked species specificity.
Antihypertensively active thiourea derivatives of the formulas ##STR1## wherein R, R.sub.1, R.sub.2, R.sub.3 and X are as hereinafter described, as well as a method of using a compound of the formula ##STR2## wherein R.sub.1 ', R.sub.2 ', R.sub.3 and X are as previously described, or a compound of formula II as an anti-hypertensive agent, is described.