Abstract: A pharmaceutical composition useful to treating dementia which comprises a compound of formula (I) or a pharmaceutically acceptable salt thereof: ##STR1## in which p is 1 and either m is 0 and n is 2 or 3 or m is 1 and n is 2, or p is 2, m is 0 and n is 2, and Z is a heterocyclic group ##STR2## in which Q represents a 3-membered divalent residue completing a 5-membered aromatic ring and comprises one or two heteroatoms selected from oxygen, nitrogen and sulphur, or three nitrogen atoms, any amino nitrogen being substituted by a C.sub.1-2 alkyl, cyclopropyl or propargyl group, and any ring carbon atom being optionally substituted by a group R.sub.1 ; or a group ##STR3## which A.sub.1, A.sub.2 and A.sub.3 complete a 5-membered aromatic ring and A.sub.1 is oxygen or sulphur, one of A.sub.2 and A.sub.3 is CR.sub.2 and the other is nitrogen or CR.sub.3, or A.sub.2 is oxygen or sulphur, one of A.sub.1 and A.sub.3 is CR.sub.2 and the other is CR.sub.3 ; and R.sub.1, R.sub.2 and R.sub.

Abstract: A compound of formula (I) useful for treating dementia or a pharmaceutically acceptable salt thereof: ##STR1## in which one of X and Y represents hydrogen and the other represents Z, where Z is a group in which Q represents a 3-membered divalent residue completing a 5-membered aromatic ring and comprises two or three nitrogen atoms, any amino nitrogen being substituted by a C.sub.1-2 alkyl, cyclopropyl or propargyl group, r represents the integer of 2 or 3, s represents an integer of 1 or 2 and t represents 0, with the proviso that when Y is hydrogen s is 1.

Abstract: A compound of formula (I) or a pharmaceutically acceptable salt thereof: ##STR1## in which one of X and Y represents hydrogen and the other represents --CH.sub.2 --Z where Z is a group ##STR2## in which Q represents a 3-membered divalent residue completing a 5-membered aromatic ring and comprises one or two heteroatoms selected from oxygen, nitrogen and sulphur, or three nitrogen atoms, any amino nitrogen being optionally substituted by a C.sub.1-2 alkyl, cyclopropyl or propargyl group, and any ring carbon atom being optionally substituted by a group R.sub.1 ; or a group ##STR3## in which A.sub.1, A.sub.2 and A.sub.3 complete a 5-membered aromtic ring and A.sub.1 is oxygen or sulphur, one of A.sub.2 and A.sub.3 is CR.sub.2 and the other is nitrogen or CR.sub.3, or A.sub.2 is oxygen or sulphur, one of A.sub.1 and A.sub.3 is CR.sub.2 and the other is CR.sub.3 ; and R.sub.1, R.sub.2 and R.sub.3 are independently selected from hydrogen, halogen, CN, OR.sub.4, SR.sub.4, N(R.sub.4).sub.2, NHCOR.sub.4, NHCOOCH.sub.