Triethylamine → 1-(Tert-butoxycarbonyl)-4-(3,4-dichlorobenzyl)piperazine

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Reaction Steps

3,4-Dichlorobenzyl bromide (35.20 g, 150 mmol) was added to a solution of N-(tert-butoxycarbonyl)piperazine (24.84 g, 130 mmol) and triethylamine (20.91 ml, 150 mmol) in chloroform (100 ml) over 30 min. After 1 h, the reaction mixture was diluted with ethyl acetate and the product was precipitated out as the hydrochloride salt by adding 1N aqueous hydrogen chloride solution. The solid product was filtered, washed with water and then resuspended in ethyl acetate. Two equivalents of 1N aqueous sodium hydroxide solution was added and the free amine was extracted into ethyl acetate. The organic layer was separated, dried over magnesium sulfate, filtered and concentrated to provide 1-(tert-butoxycarbonyl)-4-(3,4-dichlorobenzyl)piperazine (45 g).

Provenance & Evidence