Dichloromethane → 1-(2-Nitrobenzenesulfonyl)-piperazin-2-one HCl salt

Participants

Reaction Steps

To a solution of N-(t-butoxycarbonyl)-N-[2-(2-nitro-benzenesulfonylamino)-ethyl]-glycine (8.06 g, 20 mmol) in dichloromethane (100 ml) was added dicyclohexyl carbodiimide (5.16 g, 25 mmol). After stirring for 2 hours at room temperature, the precipitate was removed by filtration. The filtrate was concentrated and the residue was dissolved in ethyl actate (50 mL) and cooled to 0° C. The precipitate solid was removed and to the filtrate was added 2N-HCl in ethyl acetate (100 mL). The mixture was stirred for additional 10 h at ambient temperature. The precipitate product was filtered off, washed with ethyl acetate (500 mL), and dried in vacuo to afford the title compound as a white solid 5.39 g (79%). 1H-NMR (500 MHz; DMSO-d6) δ 9.95 (br.s, 2H), 8.38 (d, 1H), 8.04˜7.95 (m, 2H), 4.09 (dd, 2H), 3.96 (s, 2H), 3.56 (dd, 2H).

Provenance & Evidence