DIPHENYLMETHYLENE DERIVATIVE

PURPOSE: To obtain the subject derivative having acetylcholine activating action and monoamine activating action (esp. serotonin activating action), thus useful for preventing, treating or remedying dementia involved in cerebrovascular lesion, senile dementia or dementia involved in Alzheimer's disease. CONSTITUTION: This derivative is expressed by formula I [R is H, a halogen, OH, amino, a lower alkyl, (di)lower alkylamino, cyano, etc.; R is a lower alkoxycarbonyl, (substituted) carbamoyl, hydroxyimino lower alkyl, of formula II, etc.; R is H, a lower alkyl, lower alkoxyl, lower acyl, etc.; (n) is 0 or 1-4; formula III represents a single bond or double bond], specifically, e.g. 4,4- diphenyl-3-(4-pyridyl)-1-(4-pyridyl)-2-butanone. This derivative of formula I is obtained, for example, by reaction of ethyl 3,3-diphenyl-2-(4-pyridyl)propionate derived from ethyl acetate and bromodiphenylmethane with 4-picoline dissolved in tetrahydrofuran.