Novel compounds of Formula 1 are useful to treat disorders responsive to openers of the large conductance calcium-activated potassium channels: ##STR1## wherein "Het" is one of a select group of heterocyclic moieties; Z is independently for each occurrence selected from O or S; R.sup.a, R.sup.b and R.sup.c each are independently selected from hydrogen, halogen, OH, CF.sub.3, ##STR2## provided R.sup.c is not hydrogen; and when R.sup.a and R.sup.b are hydrogen, R.sup.c may be a heterocyclic moiety selected from the group consisting of imidazol-1-yl, morpholinomethyl, N-methylimidazol- 2-yl, and pyridinyl; R.sup.d and R.sup.e each are independently selected from hydrogen, halogen, CF.sub.3, NO.sub.2 or imidazol-1-yl; m, n and p each are independently selected from an integer of O or 1; and R.sup.f and R.sup.g each are independently hydrogen; C.sub.1-4 alkyl; or R.sup.f and R.sup.g, taken together with the nitrogen atom to which they are attached, is a heterocyclic moiety selected from the group consisting of N-methylpiperazine, morpholine, thiomorpholine, N-benzylpiperazine and imidazolinone.