Triethylamine → 4-tert-Butoxycarbonyl-1-[(3-chloro-1-propyl)sulfonyl]piperazine

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Reaction Steps

Amine preparation: A mixture of 1-BOC-piperazine (3.26 g), 3-chloropropanesulfonyl chloride (2.63 g) and triethylamine (2.68 mL) was stirred at room temperature in DCM (25 mL). After 2 h the reaction mixture was diluted with DCM, washed with brine, dried (MgSO4) and the solvent removed in vacuo to yield 4-(3-chloro-propane-1-sulfonyl)-piperazine-1-carboxylic acid tert-butyl ester (4.65 g). A mixture of 4-(3-chloro-propane-1-sulfonyl)-piperazine-1-carboxylic acid tert-butyl ester (4.65 g), potassium iodide (1.1 g), potassium carbonate and morpholine (1.6 mL) was heated to reflux in MeCN (100 ml). After 16 h, the reaction mixture was cooled, diluted with DCM, washed with brine, dried (MgSO4) and the solvent removed in vacuo to yield 4-(3-morpholin-4-yl-propane-1-sulfonyl)-piperazine-1-carboxylic acid tert-butyl ester (4.8 g). Treatment of this compound with HCl in DCM/MeOH yielded the desired compound, which was isolated as the hydrochloride salt.

Provenance & Evidence