The present invention relates to compounds of formula I: (I) or a
pharmaceutically acceptable acid addition salt thereof, where; X is
C(R.sup.3c.dbd. or N.dbd.; R.sup.1 is C.sub.2 C.sub.6 alkyl, substituted
C.sub.2 C.sub.6 alkyl, C.sub.3 C.sub.7 cycloalkyl, substituted C.sub.3
C.sub.7 cycloalkyl, phenyl, substituted phenyl, heterocycle, or
substituted heterocycle; R.sup.2 is hydrogen, C.sub.1 C.sub.3 n-alkyl,
C.sub.3 C.sub.6 cycloalkyl-C.sub.1 C.sub.3 alkyl, or a group of formula
II (II) provided that when R.sup.1 is C.sub.2 C.sub.6 alkyl or
substituted C.sub.2 C.sub.6 alkyl, R.sup.2 is hydrogen or methyl;
R.sup.3a, R.sub.3b, and, when X is C(R.sup.3c).dbd., R.sup.3c, are each
independently hydrogen, fluoro, or methyl, provided that no more than one
of R.sup.3a, R.sup.3b, and R.sup.3c may be other than hydrogen; R.sup.4
is hydrogen or C.sub.1 C.sub.3 alkyl; R.sup.5 is hydrogen, C.sub.1
C.sub.3 alkyl, or C.sub.3 C.sub.6 cycloalkylcarbonyl, provided that when
R.sup.3a is other than hydrogen, R.sup.5 is hydrogen; R.sup.6 is hydrogen
or C.sub.1 C.sub.6 alkyl; and n is an integer from 1 to 6 inclusively.
The compounds of the present invention are useful for activating
5-HT.sub.1F receptors, inhibiting neuronal protein extravasation, and for
the treatment or prevention of migraine in a mammal. ##STR00001##