p-Toluenesulfonic acid → 1,2,4,9-Tetrahydro-3H-carbazol-3-one

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Reaction Steps

165 g (0.72 mol) of 3,3-ethylenedioxy-1,2,3,4-tetrahydrocarbazole are dissolved in 2 l of acetone, and 3 g of p-toluenesulphonic acid are added. After the reaction solution has been heated under reflux for 4 h it is concentrated, 2 l of ethyl acetate are added, and the mixture is extracted 3 times with 1 l of saturated bicarbonate solution each time. The organic phase is dried with sodium sulphate and evaporated. The residue crystallizes from ether. In this way 118.7 g (89.1% of theory) of the product are obtained.

Provenance & Evidence