The reaction of 3-chloroaniline (I) with ethanolamine (II) by means of 47% HBr by heating at 170 C gives N-(3-chlorophenyl)ethylenediamine (III), which is condensed with ethyl 2-bromopropionate (IV) by means of triethylamine in refluxing toluene yielding the alanine derivative (V). The cyclization of (V) with refluxing 2N HCl affords the piperazinone (VI), which is reduced with LiAlH4 in ethyl ether providing 1-(3-chlorophenyl)-3-methylpiperazine (VII). The alkylation of (VII) with 1-bromo-3-chloropropane (VIII) by means of NaOH in acetone/water gives 4-(3-chlorophenyl)-1-(3-chloropropyl)-2-methylpiperazine (IX), which is condensed with the sodium salt of 1,2,4-triazolo[4,3-a]pyridin-3(2H)-one (X) in refluxing xylene/isobutanol yielding the target compound as a racemic mixture (XI). Finally, this compound is submitted to optical resolution with L-(+)-tartaric acid (XII).

The reaction of 3-chloroaniline (I) with ethanolamine (II) by means of 47% HBr by heating at 170 C gives N-(3-chlorophenyl)ethylenediamine (III), which is condensed with ethyl 2-bromopropionate (IV) by means of triethylamine in refluxing toluene yielding the alanine derivative (V). The cyclization of (V) with refluxing 2N HCl affords the piperazinone (VI), which is reduced with LiAlH4 in ethyl ether providing 1-(3-chlorophenyl)-3-methylpiperazine (VII). The alkylation of (VII) with 1-bromo-3-chloropropane (VIII) by means of NaOH in acetone/water gives 4-(3-chlorophenyl)-1-(3-chloropropyl)-2-methylpiperazine (IX), which is condensed with the sodium salt of 1,2,4-triazolo[4,3-a]pyridin-3(2H)-one (X) in refluxing xylene/isobutanol yielding the target compound as a racemic mixture (XI). Finally, this compound is submitted to optical resolution with L-(+)-tartaric acid (XII).