PURPOSE:To obtain a new isoxazole derivative capable of expecting antidemential action, antidepressing action and encephalo microcirculation- improving action as a therapeutic agent for Altzheimer syndrome, etc., and having low toxicity. CONSTITUTION:A compound, e.g. 4-chloro-5-methyl-3-(3-quinuclidinioxy)isoxazole triphenyl phosphine, expressed by formula I (R<1> is H, halogen or lower alkyl; R<2> is H, alkyl, etc.; R<3> is quanchidinyl or piperidyl). The compound is obtained by reacting 3-chloroisoxazoles expressed by formula II with hydroxypiperidines expressed by formula III (M is alkali metal) or alkali salts of hydroxypiperidines.
ISOXAZOLE DERIVATIVE