Abstract: The present invention relates to a compound selected from the group consisting of compounds of formula: ##STR1## in which: R.sup.1 is selected from the group consisting of phenyl, phenyl substituted by a radical selected from C.sub.1 -C.sub.4 alkyl, C.sub.1 -C.sub.4 alkoxy, halogen, nitro, amino and cyano, and naphthyl,R.sup.2 is selected from the group consisting of hydrogen, C.sub.1 -C.sub.4 alkyl, and phenyl, or, together with the carbon atom to which they are attached, R.sup.1 and R.sup.2 form a polycyclic ring selected from the rings derived from fluorene, xanthene, indane, tetrahydronaphthalene, dihydrodibenzocycloheptene and dibenzocycloheptene,R.sup.3 is selected from the group consisting of isopropyl and tert. butyl, and a pharmaceutically acceptable acid addition salt thereof.Such a compound is useful as anti-hypertensive drug.

Abstract: The guanidines of formula ##STR1## in which R and R' are each hydrogen or methyl and the pharmaceutically acceptable acid addition salts thereof exhibit hypotensive effects.