Isatin → Oxindole

Participants

Reaction Steps

in a polar solvent with hydrazine hydrate in the presence of a tertiary amine catalyst, characterized in that the isatin is converted to the corresponding isatin hydrazone at a temperature of from 15 to 185° C. which is directly reacted further by adding a diazabicyclooctane and/or diazabicycloundecane and/or ethyldiisopropylamine catalyst at temperatures of from 100 to 185° C. while distilling off the water of reaction formed to give the corresponding 2-oxindole of the formula which is then isolated by distilling off the solvent and crystallizing out of the reaction mixture.

Provenance & Evidence