Patent ID: 8518936

Claim:
A method for preparing a monohydrochloride of a piperazine derivative represented by the following formula (1) or a water adduct of said monohydrochloride acid addition salt, comprising: reacting the piperazine derivative with a hydrochloric acid salt of pyridine thus forming a monohydrochloride acid addition salt of said piperazine derivative, wherein said piperazine derivative is characterized by formula (1): wherein X represents an oxygen atom, Y 1 , Y 2 and Y 3 each independently represent a hydrogen or halogen atom or a lower alkyl or lower haloalkyl group, R 1 , R 2 and R 3 each independently represents a hydrogen or halogen atom or a lower alkyl, lower haloalkyl, lower alkylthio, lower haloalkoxy or lower alkoxyalkoxy group, 1 denotes an integer of from 1 to 2, m denotes an integer of from 2 to 4, and n denotes an integer of from 1 to 3.