Acaprazine

Acaprazine,ZYF Pharm Chemical

2 methods of producing of 1-(3-acetylaminopropyl)-4-(2,5-dichlorophenyl) piperazine:
1. A mixture formed by N-(3-chloropropyl)phthalimide (23.0 g), 1-(2,5- dichlorophenyl)piperazine (24.0 g), anhydrous sodium carbonate (14.0 g) and toluene (130 ml) is boiled under stirring for 30 h. The solution is then cooled, filtered, concentrated to dryness, and the residue is treated with water and ether. The ethereal extract is washed, dried and concentrated to dryness. The residue is treated with ethyl acetate and transformed into hydrochloride with ethanolic HCl. N-[3-[4-(2,5-Dichlorophenyl)-1-piperazinyl]propyl]phthalimide hydrochloride (30.0 g) is obtained, melting point 233°C (dec.).
N-[3-[4-(2,5-Dichlorophenyl)-1-piperazinyl]propyl]phthalimide (15.0 g) and 99% hydrazinehydrate (2 ml) are heated, under reflux, for 90 min. 5 N HCl (115 ml) is then added and the solution is heated for 30 min under reflux. The solution is cooled, filtered and concentrated to small volume. The residue is diluted with water, made alkaline by means of a solution of NaOH and extracted with CH2Cl2. The organic layer is dried, evaporated and distilled under reduced pressure. 7.0 g of 1-(3-aminopropyl)-4-(2,5-dichlorophenyl) piperazine are obtained.
1-(3-Aminopropyl)-4-(2,5-dichlorophenyl)piperazine (50.0 g) is dissolved in CH2Cl2, and the solution is heated under reflux. Acetic anhydride (25 ml) dissolved in CH2Cl2, (500 ml) is introduced under stirring in about 1 h. The solution is heated for 1 h and is evaporated to dryness in a rotating evaporator. The is treated with H2O, thus obtaining a solid which is separated, washed and dried at 50°C. This solid is then dissolved in ethyl acetate (about 350 ml), treated with charcoal and crystallized. 1-(3-Acetylaminopropyl)-4- (2,5-dichlorophenyl)piperazine is obtained in an almost quantitative yield, melting point 114°C.
2. Chlorosuccinimide (5.4 g) is added to a solution of 4-(m-chlorophenyl)-1- piperazinopropionitrile (5.0 g) in CH2Cl2 (100 ml). The solution is heated for a few hours and, after removal of the solvent, it is chromatographed on an alumina column. The solution is eluted with a 1:1 mixture of cyclohexane and benzene containing 0.3 % of triethylamine. 4-(2,5-Dichlorophenyl)-1- piperazinopropionitrile (2.0 g) is thus obtained.
4-(2,5-Dichlorophenyl)-1-piperazinopropionitrile (20.0 g), acetic anhydride (100 ml), anhydrous sodium sulfate (12.0 g) and a 50% solution of Ni-Raney (6 ml) are hydrogenated at 60.0 pounds per inch at 60°C in a Parr apparatus. After about half an absorption of hydrogen is complete. The reaction mixture is cooled, the is filtered and the solution is concentrated to small volume in a rotating evaporator. The residue is treated with NaOH solution and extracted several times CH2Cl2. The organic layer is washed, dried and evaporated. The residue is crystallized from ethyl acetate. 14.0 g of the 1-(3- acetylaminopropyl)-4-(2,5-dichlorophenyl)piperazine are obtained, melting point 114°C.

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