1-Piperazinecarboxylic acid, ethyl ester → HCID 54134626, compound

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Reaction Steps

Under nitrogen, 59.6 g of 4-methylmercaptophenylethyl chloride are heated with 75.7 g of 1-ethoxycarbonylpiperazine for 1.5 hours at 130°. A further 25.2 g of 1-ethoxycarbonylpiperazine are added thereto, and after 1.5 hours a further 25.2 g of 1-ethoxycarbonylpiperazine are added. After a total of 4.5 hours, the solution is poured onto ice-water, rendered strongly alkaline with concentrated NaOH and extracted with ether. Concentration by evaporation yields a mobile oil, which is purified by chromatography over silica gel (eluant: dichloromethane and dichloromethane/acetone 8:2). 90 g of the 1-[(4-methylmercaptophenyl)ethyl]-4-ethoxycarbonylpiperazine so obtained are boiled under reflux for 17 hours with 700 ml of concentrated HCl. The solution is diluted with ice-water, rendered alkaline with concentrated NaOH, extracted with ethyl acetate, concentrated by evaporation and recrystallised from ether/petroleum ether. The 1-[2-(4-methylmercaptophenyl)ethyl]piperazine melts at 52°-54°.

Provenance & Evidence