Heterocyclo-substituted azabicyclo muscannic agonists

Abstract

A compound of formula (I) or a pharmaceutically acceptable salt thereof: ##STR1## in which X represents a group ##STR2## in which p represents an integer of 2 to 4; r represents an integer of 1 or 2; s represents 0 or 1; and A represents a 3-membered divalent residue completing a 5-membered aromatic ring and comprises one or two heteroatoms selected from oxygen, nitrogen and sulphur, any amino nitrogen optionally substituted by a C.sub.1-4 alkyl group, and when (p,r,s) is (2,2,0) or (2,2,1) any A comprising 2 heteroatoms is optionally C-substituted by a methyl group, and when (p,r,s) is (2,1,0), (2,1,1) or (3,1,0) any A comprising 2 heteroatoms is optionally C-substituted by C.sub.1-2 alkyl and any A comprising one heteroatom is optionally C-substituted by a methyl group, and wherein compounds of formula (I) having two asymetric centers have the stereo-chemical configuration in which the group X and the (CH.sub.2).sub.r bridge are on the same side of the plane of the molecule which contains both bridgehead atoms and the ring carbon atom bonded to the group X. The compounds of the present invention enhance acetylcholine function via an action at muscarinic receptors within the central nervous system and are therefore of potential use in the treatment and/or prophylaxis of dementia in mammals.