Reaction #77875

Reaction equation

hydrazine hydrate

isatin

diazabicyclooctane

diazabicycloundecane

isatin hydrazone

→

2-oxindole

Conditions

Workup

1. 1
   Otheris directly reacted further
2. 2
   workup.DISTILLATIONwhile distilling off
3. 3
   Otherthe water of reaction
4. 4
   Otherformed

Procedure

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.

Source