4,5,-dihydroisoxazolylakylpiperazine derivatives having selective biological activity at dopamine D3 or D4 receptor, and preparation thereof

A method of treating schizophrenia which comprises administering to a patient an effective amount of at least one 4,5-dihydroisoxazolylalkylpiperazine derivative represented by the following formula (1), or a pharmaceutically acceptable addition salt thereof, in racemic form or as individual optical isomers:

• wherein R1 represents at least one substituent of the group consisting of an aryl group, a phenylmethyl group, a diphenylmethyl group, and pyrimidinyl group, and wherein the substituent may have one or more further substituents selected from the group consisting of C1-C6 alkyl group, C1-C6 alkoxy group, a fluorine atom and a chlorine atom;
• R2 represents at least one substituent selected from the group consisting of an aryl group, a styryl group, and a thiophene group, and wherein the substituent may have at least one further substituent, selected from the group consisting of a fluorine atom, a nitro group, a C1-C6 alkyl group, a C1-C6 alkoxy group and a phenoxy group;
• X represents CH or a nitrogen atom;
• and
• n represents 3 or 4.