Diisopropylethylamine → 3,5-dichlorophenyl-sulfonyl-L-proline methyl ester

Participants

Reaction Steps

3,5-Dichlorobenzenesulphonyl chloride (5.0 g, 20.36 mmol) was added portionwise over 30 min to a solution of L-proline methyl ester hydrochloride (3.69 g, 22.4 mmol) and DIEA (7.8 ml, 44.8 mmol) in DCM (100 ml) at 0°. The reaction mixture was stirred overnight at room temperature then concentrated in vacuo. The residue was dissolved in EtOAc (100 ml) and washed with saturated aqueous NaHCO3 (100 ml), citric acid (10%, 100 ml) and saturated aqueous NaHCO3 (100 ml). The organic phase was dried (MgSO4) and concentrated in vacuo. Column chromatography (SiO2, EtOAc/hexane, 80:20) gave the title compound (3.77 g). δH (CDCl3) 7.8 (2H, d, J 2.0 Hz, ArH), 7.5 (1H, d, J 2.0 Hz, ArH), 4.4 (1H, m, CHα), 3.7 (3H, s, CO2Me), 3.4 (2H, m, CH2N), 2.0 (4H, m, NCH2CH2CH2); m/z (ES+, 70V), 338 (MH+).

Provenance & Evidence