The present invention provides compounds of formula (I) or pharmaceutically acceptable salts thereof: where A is C1-6alkyl, C2-6alkenyl, C2-6alkynyl, C3-6cycloalkyl, arylC1-6alkyl, aryl, S(O),R1, OR1 or NR1R6; R1 is hydrogen; C1-6alkyl, C2-6alkenyl, C2-6alkynyl, C3-6cycloalkyl or C3-6cycloalkenyl each of which is optionally substituted by amino, C1-6alkylamino, di(C1-6alkyl)amino, C1-6alkoxy, C1-6alkylaminocarbonyl, one, two or three hydroxy groups, one, two or three halogen atoms or a four, five or six-membered saturated heterocyclic ring containing a nitrogen atom and optionally either an oxygen atom or a further nitrogen atom which ring is optionally substituted by C1-4alkyl on the further nitrogen atom; aryl, arylC1-6alkyl, arylC2-6alkenyl or arylC2-6alkynyl optionally substituted on the aryl ring by halogen, nitro, cyano, C1-6alkylcarbonylamino, hydroxy or C1-6alkoxy; or a five-membered aromatic ring containing 1, 2, 3 or 4 heteroatoms chosen from O, N and S provided that not more than one heteroatom is other than N, or a six-membered aromatic ring containing 1, 2, 3 or 4 nitrogen atoms, each of which rings is optionally substituted by halogen, C1-6alkoxy, C1-6alkylthio, aryl, C1-6alkyl, C2-6alkenyl or C2-6alkynyl; R2 and R3 are independently hydrogen or C1-6alkyl or together with the carbon atom to which they are attached form a C3-8 cycloalkyl group; R4 and R5 are individually hydrogen, C1-6alkyl, C2-6alkenyl, C2-6alkynyl or C3-8cycloalkyl or R12 and R13, together with the nitrogen atom to which they are attached, form a saturated 4 to 8 membered ring optionally containing an oxygen atom or a further nitrogen atom as a ring member, the further nitrogen atom being unsubstituted or substituted by C1-4alkyl, C2-4alkenyl or C2-4alkynyl; R6 is hydrogen or C1-6alkyl; p is zero, 1 or 2; and q is 0, 1 or 2; the preparation of these compounds, their use in enhancing cognition in disease states, particularly Alzheimer's disease, and methods of treatment using them.
Substituted thienlycyclohexanone derivatives for enhancing cognition