Dichloromethane → tert-Butyl 4-(thiophene-2-sulfonyl)piperazine-1-carboxylate

HRID 1972377Notes

Reaction equation

[N:1]1([C:7]([O:9][C:10]([CH3:13])([CH3:12])[CH3:11])=[O:8])[CH2:6][CH2:5][NH:4][CH2:3][CH2:2]1.C(Cl)Cl.C(N(CC)CC)C.[S:24]1[CH:28]=[CH:27][CH:26]=[C:25]1[S:29](Cl)(=[O:31])=[O:30]>O>[S:24]1[CH:28]=[CH:27][CH:26]=[C:25]1[S:29]([N:4]1[CH2:5][CH2:6][N:1]([C:7]([O:9][C:10]([CH3:13])([CH3:12])[CH3:11])=[O:8])[CH2:2][CH2:3]1)(=[O:31])=[O:30]

Participants

Conditions

Temperature: 0 °C

Procedure

A 1 L round-bottomed flask was charged with tert-butyl piperazine-1-carboxylate (20.70 g, 111 mmol, Sigma-Aldrich, St. Louis, Mo.), 300 mL of CH2Cl2, and triethylamine (17.81 mL, 128 mmol). After cooling to 0° C., 2-thiophenesulfonyl chloride (21.31 g, 117 mmol, Sigma-Aldrich, St. Louis, Mo.) was added and the reaction was stirred at 0° C. for 30 min. The mixture was diluted with water (200 mL) and the layers were separated, dried (MgSO4) and concentrated to give tert-butyl 4-(thiophen-2-ylsulfonyl)piperazine-1-carboxylate (37.0 g) as a white solid. To this solid was added 300 mL of EtOAc, and 4 N HCl in dioxane (100 mL). The mixture was heated to 65° C. to give a clear solution. Over the course of 2 h, a white precipitate formed. The white precipitate was collected by filtration and dried under reduced pressure to give 4-(thiophen-2-ylsulfonyl)piperazine hydrochloride (26.0 g).

Workup

customthe layers were separated
dry with materialdried (MgSO4)
concentrationconcentrated

Sources & evidence

ORD record: ord-da40e23420654add8888a60e12c35efc
Source dataset: uspto-grants-2013_04
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US08431563B2

Reaction notes

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