| abstract |
Compounds of formula (l) :n [in which : R 1 is hydrogen, halogen or alkyl ; R 2 is hydrogen, alkyl, optionally substituted phenyl or a heterocycle; or R 1 and R 2 together form a group of formula -CR 4 =CR 5 -CR 6 =CR 7 -, where R 4 , R 5 , R 6 and R 7 are hydrogen, halogen, alkyl group, alkoxy, halomethyl, alkylamino, dialkylamino, hydroxy, nitro, aliphatic carboxylic acylamino or amino ; and R 3 is piperidyl, substituted piperidyl or quinuclidinyl] are useful in the treatment and prophylaxis of cognitive disorders, notably senile dementia, including Alzheimer's disease. Processes for preparing the compounds are also provided. |