Enantiomers of 1-[(4-chlorophenyl) phenylmethyl]-4-[(4-methylphenyl) sulfonyl] piperazine

A process for the preparation of the levorotatory and dextrorotatory enantiomers of 1-[(4-chlorophenyl)phenylmethyl]piperazine of the formula

• 11
• which comprises subjecting an enantiomer of 1-[(4-chlorophenyl)phenylmethyl]-4-[(4-methylphenyl)sulfonyl]piperazine of the formula
• 12
• to hydrolysis with hydrobromic acid, in acetic acid medium, in the presence of a phenolic compound, and at a temperature of between 18 and 100° C.

A process for the preparation of the levorotatory and dextrorotatory enantiomers of a 1-1(4-chlorophenyl)phenylmethyl]piperazine of the formula

• 13
• wherein R is a methyl, (3-methylphenyl)methyl, (4-tert-butylphenyl)methyl, 2-(2-hydroxyethoxy)ethyl, 2-[2-[2-hydroxyethoxy)ethoxy]ethyl, 2-(carboxymethoxy)ethyl, 2-(methoxycarbonylmethoxy)ethyl or 2-(carboxymethoxy)ethyl radical, which comprises reacting an enantiomer of 1-[(4-chlorophenyl)phenylmethyl]piperazine of the formula
• 14
• while hot, with a halide of the formula RX
• wherein R has the meaning given above and X represents a halogen atom.

A compound selected from the group consisting of

• the levorotatory dihydrochloride of 1-[(4-chlorophenyl)phenylmethyl]-4-[(3-methylphenyl)methyl]piperazine;
• the dextrorotatory dihydrochloride of 1-[(4-chlorophenyl)phenylmethyl]-4-[(3-methylphenyl)methyl]piperazine;
• the levorotatory dihydrochloride of 1-[(4-tert-butylphenyl)methyl]-4-[(4 chlorophenyl)phenylmethyl]piperazine;
• the dextrorotatory dihydrochloride of 1-[(4-tert-butylphenyl)methyl]-4-[(4-chlorophenyl)phenylmethyl]piperazine;
• the levorotatory dihydrochloride of 2-[2-[4-[(4-chlorophenyl)phenylmethyl]-1-piperazinyl]ethoxy]ethanol;
• the dextrorotatory dihydrochloride of 2-[2-[4-[(4-chlorophenyl)phenylmethyl]-1-piperazinyl]ethoxy]ethanol;
• the levorotatory dibydrochloride of 2-[2-[2-[4-[(4-chlorophenyl)phenylmethyl]-1-piperazinyl]ethoxy]ethoxy]ethanol;
• the dextrorotatory dihydrochloride of 2-[2-[2-[4-[(4-chlorophenyl)phenylmethyl]-1-piperazinyl]ethoxy]ethoxy]ethanol;
• the levorotatory 2-[2-[(4-[(4-chlorophenyl)phenylmethyl]-1-piperazinyl]ethoxy]acetamide and its dextrorotatory dihydrochloride;
• the dextrorotatory 2-[2-[4-[(4-chlorophenyl)phenylmethyl)-1-piperazinyl]ethoxy]acetamide and its levorotatory dihydrochloride;
• the levorotatory dimaleate of methyl 2-[2-[4-[(4-chlorophenyl)phenylmethyl]-1-piperazinyl]ethoxy]acetate and
• the dextrorotatory dimaleate of methyl 2-[2-[4-[(4-chlorophenyl)phenylmethyl]-1-piperazinyl]ethoxy]acetate.