| abstract |
The present invention provides a compound of formula (I)or a salt, ester or amide thereof: wherein R<sup>1</sup> is -CH<sub>2</sub>-CH<sub>2</sub>-, CH<sub>2</sub>-O- or -O-CH<sub>2</sub>-: R<sup>2</sup> and R<sup>3</sup> are the same or different and are each hydrogen, C<sub>1-4</sub> alkyl or taken together with the nitrogen comprise a nitrogen-containing heterocyclic ring having four to six ring members; R<sup>4</sup> is a single bond or a C<sub>1-7</sub> bivalent aliphatic hydrocarbon group may be joined to the aromatic ring system at the 2, 3. 8 or 9 positions; n is 0 to 3. processes for its preparation and intermediates therefor, pharmaceutical compositions containing it and its use in medicine. |