Question

In each reaction box, place the best reagent and conditions from the list below. The first reagent is right, stuck beyond that one.

Answer 1

General guidance

Concepts and reason

The concept used to solve this problem is by using the given reagents, possible products will be formed in each step and then label it exactly in the given boxes in order to form the exact product.

Here, the starting reactant is 1-bromo-3-methylbenzene and the final product is N,N-diethyl-3-methylbenzamide.

Fundamentals

Sodium amide (${\\rm{NaN}}{{\\rm{H}}_2}$) is used as base, which abstract the proton.

Mg in the presence of ether forms a Grignard reagent.

Carbon dioxide reacts with Grignard reagent followed by the hydrolysis gives carboxylic acid.

Thionyl chloride (${\\rm{SOC}}{{\\rm{l}}_2}$) converts the acid to acid chloride.

Step-by-step

Step 1 of 5

The reaction is as follows:

MgBr Mg, ether 1-bromo-3-methylbenzene m-tolylmagnesium bromide

Explanation | Hint for next step

Treatment of 1-bromo-3-methylbenzene with magnesium in the presence of ether gives m-tolylmagnesium bromide.

Step 2 of 5

The reaction is as follows:

MgBr CO2 m-tolylmagnesium bromide 3-methylbenzoate

Explanation | Common mistakes | Hint for next step

Treatment of Grignard reagent with carbon dioxide forms a carboxylate ion. Here, the Grignard reagent (nucleophile) attacks the electrophilic carbon atom of carbon dioxide and forms a new C-C bond by the cleavage of pi bond.

Step 3 of 5

The reaction is as follows:

\u043e\u043d H30 3-methylbenzoate 3-methylbenzoic acid

Explanation | Hint for next step

The carboxylate ion is protonated with the aqueous acid and forms the carboxylic acid.

Step 4 of 5

The reaction is as follows:

\u043e\u043d CI SOCI2 3-methylbenzoic acid 3-methylbenzoyl chloride

Explanation | Hint for next step

Treatment of 3-methylbenzoic acid with thionyl chloride gives 3-methylbenzoyl chloride.

Step 5 of 5

The reaction is as follows:

CI NH(CH2CH32, (2 equiv) 3-methylbenzoyl chloride N,N-diethyl-3-methylbenzamide

The best reagents for the conversion of 1-bromo-3-methylbenzene to N,N-diethyl-3-methylbenzamide is as follows:

1) 2) Mg, ether CO2 3) 4) 5) NH(CH2CH3)2, (2 equiv.) H30 SOCl2 DEET (the active ingredient in over the counter insect repellant)

Treatment of 3-methylbenzoyl chloride with two equivalents of diethyl amine forms the desired compound.

Answer

The best reagents for the conversion of 1-bromo-3-methylbenzene to N,N-diethyl-3-methylbenzamide is as follows:

1) 2) Mg, ether CO2 3) 4) 5) NH(CH2CH3)2, (2 equiv.) H30 SOCl2 DEET (the active ingredient in over the counter insect repellant)

Answer only

The best reagents for the conversion of 1-bromo-3-methylbenzene to N,N-diethyl-3-methylbenzamide is as follows:

1) 2) Mg, ether CO2 3) 4) 5) NH(CH2CH3)2, (2 equiv.) H30 SOCl2 DEET (the active ingredient in over the counter insect repellant)