Compounds of the formula ##STR1## wherein R.sup.1, R.sup.2 and R.sup.3 are the same or different and are hydrogen, C.sub.1 to C.sub.6 alkyl, C.sub.6 to C.sub.12 carbocyclic aryl or aralkyl of 1 to 6 carbon atoms in the alkyl moiety and 6 to 12 carbon atoms in the carbocyclic aryl moiety; R.sup.4 and R.sup.5 are the same or different and are hydrogen or C.sub.1 to C.sub.6 alkyl; and R.sup.6 and R.sup.7 are the same or different and are hydrogen, C.sub.1 to C.sub.6 alkyl or C.sub.1 to C.sub.6 alkoxy. Methods for preparing these compounds are also disclosed. The compounds are useful as antihypertensives and as diuretics. They also function as antihistamines and as bronchodilating agents and are therefore effective in inhibiting the effects of allergic reactions. They are also of use in the treatment of migraine and in the treatment of vasospastic disorders.