Chlorosulfonyl isocyanate → 4-(3,4-Dichlorophenyl)azetidin-2-one

Participants

Reaction Conditions

Reaction Steps

To chlorosulfonyl isocyanate (CSI) (2.46 ml) in diethyl ether (8 ml) was added dropwise with stirring 3,4-dichlorostyrene (4.89 g, 28.3 mmol). The reaction was heated to 35° C. for 90 min after which time a further 1 ml CSI was added. The reaction was left for 16 h at 35° C., then the oil bath temperature was increased to 70° C. and the ether distilled off. The reaction was stirred at 70° C. for 1 h then cooled and slurried in dichloromethane (50 ml), and added portionwise with stirring to water containing sodium bisulfite (10 g) and potassium carbonate (15 g), using an ice bath for cooling. After stirring for 30 min. the phases were separated and the organic phase dried (MgSO4) to give a yellow oil (4 g). Purification by column chromatography on silica gel eluting with 0-50% dichloromethane in hexane gave the title compound as a white solid, (2.6 g, 43%). δH (CDCl3) 2.85 (1H, dd), 3.45 (1H, m), 4.7 (1H, m), 6.35 (1H, bs), 7.25 (1H, m), 7.45 (2H, m).

Provenance & Evidence