2-Sulfobenzoic acid cyclic anhydride → HCID 18704493, compound

Participants

Reaction Steps

To a suspension of 4-methyl-4-hydroxymethyl-1-phenyl-3-pyrazolidinone (dimezone-S) (10 g, 48.5 mmol) in dry acetonitrile (200 ml), was added 2-sulfobenzoic acid cyclic anhydride (8.9 g, 48.5 mmol) in a single portion at room temperature with stirring. The reaction mixture was heated to reflux under nitrogen until complete dissolution was observed. The reflux was continued for 24 hours and the mixture was cooled in an ice/water bath for 2 hours. A solid precipitate was obtained which was recovered by filtration and washed with ice cooled acetonitrile. After drying under vacuum, 17.9 g (95%) of 4-methyl-3-oxo-1-phenyl-pyrazolidin-4-yl)methyl 2-sulfobenzoate (Compound II) were isolated as an off-white solid.

Provenance & Evidence