The present invention relates to compounds of formula I: ##STR00001## or a pharmaceutically acceptable acid addition salt thereof, where; X is --C(R.sup.4).dbd. or --N.dbd.; Ar is phenyl, substituted phenyl, heterocycle, or substituted heterocycle; R.sup.1 and R.sup.2 are independently hydrogen or C.sub.1-C.sub.3 alkyl; R.sup.3 is hydrogen, fluoro, or methyl; when X is --C(R.sup.4).dbd.,R.sup.4 is hydrogen, fluoro, or methyl, provided that no more than one of R.sup.3and R.sup.4 may be other than hydrogen; and R.sup.5 is hydrogen, methyl, or ethyl. The compounds of the present invention are useful for activating 5-HT.sub.1F receptors, inhibiting dural protein extravasation, and for the treatment or prevention of migraine in a mammal.