Nitration and Nitrosation of Indoles

What is the product formed when indole is nitrated with benzoyl nitrate in acetonitrile?

What is the position of nitrosation of 2-methylindole with sodium nitrite in the presence of acetic acid?

What is the product formed when 3-methylindole is nitrosated?

What is the product formed when indole is chlorinated with sulfuryl chloride?

What is the product formed when indole is brominated?

What is the product formed when indole is sulfonated with pyridine-sulfur trioxide complex?

What is the product formed when indole undergoes Vilsmeier-Haack formylation?

What is the position of bromination of indole if the position-3 is already substituted?

What is the product formed when indole is reacted with sulfuryl chloride in excess?

What is the product formed when 2-methylindole is nitrosated?

Nitration

Nitration of indoles with different nitrating agents depends on reaction conditions due to acid sensitivity of indole nucleus.
3-Nitroindole is produced when indole is nitrated with benzoyl nitrate in acetonitrile or with ethyl nitrate in the presence of sodium ethoxide at low temperature.

Nitrosation

2-Methylindole is nitrosated with sodium nitrite in the presence of acetic acid, forming 3-oximino-2-methylindole (a form of 3-nitroso-2-methylindole).
3-Methylindole is nitrosated to form N-nitroso-3-methylindole.

Halogenation

Chlorination of indole with sulfuryl chloride produces 3-chloroindole.
Excess sulfuryl chloride reacts with 3-chloroindole to form 2,3-dichloroindole via 3,3-dichloro-3H-indole.
Bromination of indole occurs at the position-3, forming 3-bromoindole.
If position-3 is already substituted, bromination takes place at the position-2.

Sulfonation

Indole is sulfonated with pyridine-sulfur trioxide complex to form indole-3-sulfonic acid.
If position-3 is already occupied, sulfonation occurs at the position-2 via initial reversible sulfonation at position-3.

Vilsmeier-Haack Formylation

Indole undergoes Vilsmeier-Haack formylation with N,N-dimethylformamide (DMF) in the presence of phosphorus oxychloride, forming 3-formylindole.

This quiz covers the reactions of indoles with electrophiles, specifically nitration and nitrosation, and the factors that influence the products formed. It explores the effects of different reaction conditions and nitrating agents on the outcome of these reactions.