The present invention relates to compounds of formula I ##STR1## or a salt, ester or amide thereof; wherein R.sup.1 is --CH.sub.2 --CH.sub.2 --, CH.sub.2 --O-- or --O--CH.sub.2 --; R.sup.2 and R.sup.3 are the same or different and are each hydrogen, C.sub.1-4 alkyl or taken together with the nitrogen comprise a nitrogen-containing heterocyclic ring having four to six ring members; R.sup.4 is a single bond or a C.sub.1-7 bivalent aliphatic hydrocarbon group and may be joined to the aromatic ring system at the 2,3,8 or 9 positions; n is 0 to 3, and their use as antihistamine and antiasthma agents.