Ethanol → tert-Butyl 4-(4-aminophenylsulfonyl)piperazine-1-carboxylate

Temperature

80 °C

4-(4-Nitro-benzenesulfonyl)-piperazine-1-carboxylic acid tert-butyl ester (10.0 g, 27 mmol) was suspended in a 5:1 mixture of ethanol and water (80 ml). To this solution was added iron powder (3.9 g, 70.2 mmol) and saturated ammonium chloride solution (8 ml), the mixture was heated to 80° C. for three hours. After this time, the reaction mixture was cooled to room temperature and filtered through a pad of celite, the celite was washed with ethanol (10 ml) and ethyl acetate (50 ml) and the solution was concentrated under vacuum. The resulting residue was partitioned between DCM (50 ml) and water (20 ml), the organic layer was separated, dried with MgSO4, filtered and concentrated to afford the title compound (1.5 g, 89% yield) as a white solid. δH (500 MHz, CDCl3) 7.53 (2H, d), 6.73 (2H, d), 4.36 (2H, br s), 3.56-3.49 (4H, m), 2.98-2.91 (4H, m), 1.42 (9H, s). Tr=1.81 min, m/z (ES+) ([(M−100)+H]+) 242.

1. temperatureAfter this time, the reaction mixture was cooled to room temperature
2. filtrationfiltered through a pad of celite
3. washthe celite was washed with ethanol (10 ml) and ethyl acetate (50 ml)
4. concentrationthe solution was concentrated under vacuum
5. customThe resulting residue was partitioned between DCM (50 ml) and water (20 ml)
6. customthe organic layer was separated
7. dry with materialdried with MgSO4
8. filtrationfiltered
9. concentrationconcentrated

ORD record

ord-6b468b34592a4c7bb9d2298f14e2f378

Source dataset

uspto-grants-2015_02

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08946197B2