| abstract |
Compounds of formula (I), in which R1 and R2 are each separately selected from a phenyl group which is unsubstituted or substituted by one or more groups selected from alkyl, alkoxy, alkylenedioxy, halogeno, halogeno substituted alkyl, hydroxy and nitro, R3 and R4 are each hydrogen or together are an oxo group and R5 is an aromatic group, the compound optionally being in the form of a physiologically acceptable acid addition or quaternary ammonium salt, are of value as selective antagonists of the M3 muscarinic receptor. |