Triethylamine → 4-[2-(1,1-Dioxo-isothiazolidin-2-yl)-ethyl]-piperazine-1-carboxylic acid tert-butyl ester

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Reaction Steps

To a stirred solution of 1-Boc-4-(2-aminoethyl)-piperazine (1.26 g, 6.8 mmol) and triethylamine (1 mL) in THF (10 ML), 3-chloro-propylsulfonyl chloride (Aldrich, 0.68 mL, 6.94 mmol) was added slowly at room temperature. The mixture was stirred for 30 minutes at and the reaction was quenched with water. The new mixture was extracted with ethyl acetate and the extracts were combined and dried (Na2SO4). The solution was concentrated and the residue was dissolved in THF (20 mL) and Cs2CO3 (500 mg), NaI (80 mg) were added and the mixture was stirred at reflux overnight. The mixture was cooled to room temperature and poured into water. The new mixture was extracted with ethyl acetate (3×15 mL) and the extracts were combined and dried (Na2SO4). Removal of the solvent on a rotary evaporator gave a solid. 2.01 g.

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