Diisopropylethylamine → 1-[4-(Trifluoromethoxy)benzenesulfonyl]piperazine

Participants

Reaction Steps

To a solution of 1,1-dimethylethyl 1-piperazinecarboxylate (5 g, 26.8 mmol) in DCM (200 ml) was added DIPEA (9.85 ml, 56.4 mmol) and then 4-[(trifluoromethyl)oxy]benzenesulfonyl chloride (4.55 ml, 26.8 mmol). The reaction mixture was stirred for 1.5 hours at rt. The reaction mixture was then evaporated to dryness in vacuo. The residue was then dissolved in 1,4-dioxane (100 ml) and 4M HCl in 1,4-dioxane (50 ml) was added, along with a few drops of distilled water. The reaction mixture was stirred for 3 hrs. Then the reaction mixture was evaporated to dryness in vacuo. The residue was dissolved in DCM (200 ml) and washed with 2M aq. NaOH (50 ml, twice). The organic layer was dried over anhydrous magnesium sulphate, the solid removed by filtration, and filtrate evaporated to dryness in vacuo. The residue was not a solid so was dissolved in ether and evaporated in vacuo to remove any remaining solvent. The title compound (8.02 g) was obtained as a pale yellow solid.

Provenance & Evidence