Triethylamine → (3-Methoxyphenyl)(piperazin-1-yl)methanone

Participants

Reaction Steps

3.42 g of benzylpiperazine are dissolved in 35 ml of methylene chloride and there are added thereto 2.1 g of triethylamine and then, dropwise and while cooling with ice, 3.4 g of 3-methoxybenzoyl chloride in 30 ml of methylene chloride. The reaction mixture is stirred overnight at room temperature and then washed with H2O. After being dried over sodium sulphate, the solution is concentrated to dryness by evaporation in vacuo. The oily 1-benzyl-4-(3-methoxybenzoyl)-piperazine is dissolved in 150 ml of fine spirit and debenzylated over 0.5 g of Pd-C. When the hydrogenation is complete, the catalyst is filtered off from the mixture and the filtrate is concentrated to dryness by evaporation in vacuo. The oily N-(3-methoxybenzoyl)-piperazine so obtained is placed in a sulphonating flask with 3.8 g of p-chlorophenethyl bromide and heated to 100°. At 60° a slight exothermic reaction takes place. After 3 hours at 100° , the mixture is cooled and dissolved in 400 ml of methylene chloride, and then 2N NaOH is added thereto; the whole is extracted by shaking and the methylene chloride phase is washed twice with H2O. The organic phase is dried over Na2SO4 and concentrated to dryness by evaporation in vacuo. The oily 1-[2-(4-chlorophenyl)-ethyl]-4-(3-methoxybenzoyl)piperazine is dissolved in isopropanol, and hydrochloric acid is added thereto. After the addition of ether, the hydrochloride, which has a melting point of 230°-232°, crystallises.

Provenance & Evidence