| abstract |
The present invention relates to compounds of formula I <IMAGE> (I) or a salt, ester or amide thereof; wherein R1 is -CH2-CH2-, CH2-O- or -O-CH2-; R2 and R3 are the same or different and are each hydrogen, C1-4 alkyl or taken together with the nitrogen comprise a nitrogen-containing heterocyclic ring having four to six ring members; R4 is a single bond or a C1-7 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. |