The invention provides compounds of formula (I), ##STR1## wherein R.sup.1 represents C.sub.1-4 alkoxy optionally substituted by one or more fluorine atoms; R.sup.2 represents H or C.sub.1-6 alkoxy optionally substituted by one or more fluorine atoms; R.sup.3 represents one or more groups independently selected from H, halogen, C.sub.1-4 alkoxy and CF.sub.3 ; in addition, R.sup.2 and one R.sup.3 group may together represent --OCH.sub.2 --, the methylene group being attached to the ortho-position of the pendant phenyl ring; R.sup.4 represents a 4-, 5- or 6-membered heterocyclic ring containing 1 or 2 heteroatoms selected from N, O and S, the ring being optionally fused to a benzene ring or a 5- or 6-membered heterocyclic ring containing 1 or 2 heteroatoms selected from N, O and S, the ring system as a whole being optionally substituted; X represents CH or N; and L is absent or represents a cyclic group or an open chain group; and pharmaceutically acceptable salts thereof. The compounds of formula (I) are useful in the treatment of inter alia benign prostatic hyperplasia.