p-Toluenesulfonic acid monohydrate → HCID 67154076, compound

Participants

Reaction Conditions

Reaction Steps

6.5 g of (2,3-dioxo-2,3-dihydro-1H-indol-5-yl)cyclopropanecarboxylic acid are dissolved in 100 ml of ethanol, and 500 mg of toluene-4-sulfonic acid monohydrate are added. The mixture is heated at 80° C. for 1 h and subsequently evaporated in vacuo. The residue is taken up in 100 ml of water and 100 ml of ethyl acetate and stirred at 60° C. for a further 12 h. The mixture is neutralised using sodium hydrogencarbonate, and the organic phase is separated off. The aqueous phase is washed a further twice with 100 ml of ethyl acetate each time. The combined organic phases are dried over sodium sulfate, filtered and evaporated to dryness in vacuo, giving 6.7 g (92%) of ethyl 1-(2,3-dioxoindolin-5-yl)cyclopropanecarboxylate; LC-MS retention time: 1.30 min.

Provenance & Evidence