(a). 3,4-Diethyl-δ2-1,2,4-triazolin-5-one (62 g) is dissolved in anhydrous
dioxane (about 500 ml) and NaH (21 g) in a 50 percent oily suspension is
added. The solution is heated for 30 min under reflux and NmetachlorophenyI-
N'-(3-chloro-n-propyl)piperazine (119 g) is added under
stirring. The solution is heated for 20 hours under reflux. The solvent is then
eliminated under reduced pressure and the residue is treated with 2 N HCl.
The solution is washed with ether so as to eliminate the oil present in the
hydride solution, and made alkaline with 50% K2CO3. It is extracted with
ether and dried, the solvent is eliminated and the residue is distilled under
reduced pressure. 115 g of 2-(3-(4-(3-chlorophenyl)-1-piperazinyl)propyl)-
4,5-diethyl-2,4-dihydro-1,2,4-triazol-3-one are obtained. B.P. 230°C/0.5 mm.
2-(3-(4-(3-Chlorophenyl)-1-piperazinyl)propyl)-4,5-diethyl-2,4-dihydro-1,2,4-
triazol-3-one hydrochloride was prepared by standard procedures, melting
point 197-198°C (recrystallization from isopropanol).
(b). 3,4-Diethyl-δ2-1,2,4-triazolin-5-one (1 g) and 3-bromo-1-chloropropane
(6.6 g) are added to a solution of Na (0.98 g) in methanol (20 ml). The
solution is refluxed until the pH becomes neutral, poured into water, extracted
with ether. The solvent is eliminated and the residual oil is distilled. 1-(3-
Chloropropyl)-3,4-diethyl-δ2-1,2,4-triazolin-5-one boils at 121°C/0.05 mm.
1-(3-Chloropropyl)-3,4-diethyl-δ2-1,2,4-triazolin-5-one (1.0 g), NmetachlorophenyIpiperazine
(0.9 g) and triethylamine (0.46 g) in toluene (25
ml) are refluxed for 12 hours. The solution is treated with 5 N NaOH,
extracted with ether and steam-distilled. The residue is extracted with ether
and the ethereal solution is treated with ethereal HCl. 2-(3-(4-(3-
Chlorophenyl)-1-piperazinyl)propyl)-4,5-diethyl-2,4-dihydro-1,2,4-triazol-3-
one hydrochloride has melting point 197-198°C (recrystallization from
isopropanol).
