Abstract: This invention relates to novel potassium channel activators and their acid addition salts. The compounds of the invention as potassium channel activators/openers have therapeutic value in a number of physiological areas such as hypertension, cardiac ischemia, cerebral ischemia, broncho constriction and neurodegenerative diseases. Pharmaceutical compositions are proposed for the compounds which are of the following formulae: ##STR1## wherein: R is H or OH;- - - the dotted line at position 3,4 represents the presence or absence of a double bond. ##STR2## the pharmaceutically acceptable acid addition salts thereof, with the provisos that:a) R is H when 3,4 is a double bond; andb) R is OH when 3,4 is a single bond.