Process for producing acid adduct salt of polyacidic base compound

A method for preparing an acid addition salt of a piperazine derivative represented by the following formula (1) or a water adduct of said acid addition salt, which is characterized by reacting the piperazine derivative with an acid salt of pyridine:

• wherein X represents —NH—, an oxygen atom or a sulfur atom, Y1, Y2 and Y3 each independently represent a hydrogen or halogen atom or a lower alkyl or lower haloalkyl group, R1, R2 and R3 each independently represent 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.

2-[4-[2-(Benzimidazol-2-ylthio)ethyl]piperazin-1-yl]-N-[2,4-bis(methylthio)-6-methyl-3-pyridyl]acetamide monohydrochloride or a water adduct thereof, 2-[4-[2-(5,6-difluorobenzimidazol-2-ylthio)ethyl]piperazin-1-yl]-N-[2,4-bis(2,2,2-trifluoroethoxy)-6-methyl-3-pyridyl]acetamide monohydrochloride or a water adduct thereof, 2-[4-[2-(benzimidazol-2-ylthio)ethyl]piperazin-1-yl]-N-[2,4-bis(2,2,2-trifluoroethoxy)-6-methyl-3-pyridyl]acetamide dihydrochloride or a water adduct thereof, 2-[4-[2-(benzoxazol-2-ylthio)ethyl]piperazin-1-yl]-N-[2,4-bis(2,2,2-trifluoroethoxy)-6-methyl-3-pyridyl]acetamide monohydrochloride or a water adduct thereof, 2-[4-[2-(benzothiazol-2-ylthio)ethyl]piperazin-1-yl]-N-[2,6-dimethyl-4-trifluoromethyl-3-pyridyl]acetamide dihydrochloride or a water adduct thereof, 2-[4-[2-(5-trifluoromethylbenzoxazol-2-ylthio)ethyl]piperazin-1-yl]-N-[2,4-bis(methylthio)-6-methyl-3-pyridyl]acetamide monohydrochloride or a water adduct thereof, or 2-[4-[2-(benzoxazol-2-ylthio)ethyl]piperazin-1-yl]-N-[2-(2-methoxyethoxy)-4-(2,2,2-trifluoroethoxy)-6-methyl-3-pyridyl]acetamide monohydrochloride or a water adduct thereof.

2-[4-[2-(Benzimidazol-2-ylthio)ethyl]piperazin-1-yl]-N-[2,4-bis(methylthio)-6-methyl-3-pyridyl]acetamide monohydrochloride crystal or a water adduct thereof, 2-[4-[2-(5,6-difluorobenzimidazol-2-ylthio)ethyl]piperazin-1-yl]-N-[2,4-bis(2,2,2-trifluoroethoxy)-6-methyl-3-pyridyl]acetamide monohydrochloride crystal or a water adduct thereof, 2-[4-[2-(benzimidazol-2-ylthio)ethyl]piperazin-1-yl]-N-[2,4-bis(2,2,2-trifluoroethoxy)-6-methyl-3-pyridyl]acetamide dihydrochloride crystal or a water adduct thereof, 2-[4-[2-(benzoxazol-2-ylthio)ethyl]piperazin-1-yl]-N-[2,4-bis(2,2,2-trifluoroethoxy)-6-methyl-3-pyridyl]acetamide monohydrochloride crystal or a water adduct thereof, 2-[4-[2-(benzothiazol-2-ylthio)ethyl]piperazin-1-yl]-N-[2,6-dimethyl-4-trifluoromethyl-3-pyridyl]acetamide dihydrochloride crystal or a water adduct thereof, 2-[4-[2-(5-trifluoromethylbenzoxazol-2-ylthio)ethyl]piperazin-1-yl]-N-[2,4-bis(methylthio)-6-methyl-3-pyridyl]acetamide monohydrochloride crystal or a water adduct thereof, or 2-[4-[2-(benzoxazol-2-ylthio)ethyl]piperazin-1-yl]-N-[2-(2-methoxyethoxy)-4-(2,2,2-trifluoroethoxy)-6-methyl-3-pyridyl]acetamide monohydrochloride crystal or a water adduct thereof.