a) Leaving groups near the ring
Indole throws out to the outgoing groups located in the neighboring situation to a ring. In addition, it is necessary that the chain that has the leaving group is located in position 3 of the ring.
![indole derivatives 01](/images/stories/heterociclos/indol/derivados-indol-01.png)
b) Carboxylic acids![indole derivatives 02](/images/stories/heterociclos/indol/derivados-indol-02.png)
The carboxylic group, both in position 2 and 3, decarboxylates on heating.
![indole derivatives 02](/images/stories/heterociclos/indol/derivados-indol-02.png)
c) Hydroxy derivatives![indole derivatives 03](/images/stories/heterociclos/indol/derivados-indol-03.png)
The 2- and 3-hydroxy derivatives of the indole tautomerize to the keto form.
![indole derivatives 03](/images/stories/heterociclos/indol/derivados-indol-03.png)