Question

1. Give the structures of the two major products in the following reaction.

2. Draw the major organic product of the following Friedel–Crafts alkylation. (An excess of benzene is present.)

3. Draw the structure of the major nitration product from the reaction of nitric acid with 1,3-dimethylbenzene. Show all formal charges.

Answer 1

Concepts and reason

A bromination reaction is an electrophilic substitution reaction using reagent and the electrophile is ion. The selectivity of substitution on a benzene ring depends on the type of substituent present on it.

Fredal crafts alkylation reaction is an electrophilic substitution reaction in which the alkyl group acts as an electrophile and is substituted on a benzene ring using Lewis acids such as

In organic synthesis, an electrophilic aromatic substitution reaction is one important class organic reaction. In this, the Nitro group can replace the hydrogen atom attached on the aromatic ring. In this, the aromatic organic compound is treated with concentrated nitric acid and concentrated sulfuric acid The temperature of the reaction should not be more than 323K. The substitution of Nitro group takes place on the aromatic ring.

Fundamentals

Bromination: A bromination reaction is the addition of a bromine atom on a reactant molecule via electrophilic substation mechanism. The reagent is and generates ion as an electrophile that reacts with a nucleophilic center on the benzene ring. The selectivity of substitution on the benzene ring depends on the type of substituent present on it.

Fredal crafts alkylation: In this reaction, an alkylhalide reacts with a Lewis acid and generates an electrophile that attacks the benzene ring and forms an alkyl-substituted benzene ring.

Nitration: The nitration reaction is an aromatic electrophilic substitution reaction in which group attacks on the electron-rich aromatic ring followed by the removal of hydrogen which takes place to give the final product.

The general reaction scheme is given below:

Generation electrophile is given below:

The resonance structures for chlorobenzene are given below:

From the above structures, it is clear that the substitution of an electrophile takes place only at the ‘ortho and para’ carbons’ negative charge (nucleophilic center) and that is shown in resonance structures.

The products of the reaction are given below:

The reaction of (Chloromethyl) cyclohexane with

The mechanism for the attack of electrophile is given below:

The mechanism for formation of nitronium ion is given below:

The products of the reaction are given below:

Ans:

The structures of the two major products in the following reaction are given below:

The major organic product of the following Friedel–Crafts alkylation is given below:

The structure of the major nitration product from the reaction of nitric acid with 1,3-dimethylbenzene is given below: