Dimethylformamide → HCID 178473095, compound

Participants

Reaction Steps

To a suspension of 0.88 g (22 mmol) of sodium hydride (60% dispersion in mineral oil) in THF (50 ml) was added under ice-cooling, 2.94 g (10 mmol) of 4-(5-chloroindol-3-yl)-2-hydroxy-4-oxo-2-butenoic acid ethyl ester prepared in Example 1 (1). After stirring for 15 min at room temperature, to the mixture was added dropwise a solution of 2.12 g (12 mmol) of benzenesulfonyl chloride in THF (20 ml). After stirring for 2 hours at room temperature, to the mixture was added DMF (8 ml). After stirring for additional 30 min, the reaction mixture was poured into ice-water containing 1N hydrochloric acid, and extracted with ethyl acetate. The organic layer was washed with water and saturated brine, and then dried. The solvent was concentrated and the residue was crystallized from ether to give crude crystal, which was washed with ether to give 3.75 g of the titled compound. Yield: 87%. Subsequent recrystallization from ethyl acetate afforded the pure ester, melted at. 156-157° C.

Provenance & Evidence