Question

Show how the following compounds can be synthesized from benzene:

a. N,N,N-trimethylanilinium iodide

b. 2-methyl-4-nitrophenol

c. p-benzylchlorobenzene

d. benzyl methyl ether

e. p-nitroaniline

f. m-bromoiodobenzene

g. p-dideuteriobenzene

h. p-nitro-N-methylaniline

i. 1-bromo-3-nitrobenzene

Short answer

The synthesis of above compounds from benzene isshown below.

d)

Step-by-step solution

Synthesis of N,N,N-trimethylanilinium iodide (a)

The addition of nitrating mixture to benzene gives nitrobenzene.When it undergoes reduction reaction in presence of Pd catalyst, we get the desired product,aminobenzene.When excess of methyl iodide is added to the aminobenzene, we get the product N, N, N-trimethylanilinium iodide.

Synthesis of2-methyl-4-nitrophenol (b)

Fridedel crafts alkylation used in the first step gives the compound toluene from benzene. Nitration converts toluene to nitro group substituted benzene compound. In the next step, nitro group reduces to amino group in the presence of Pd catalyst and then converts to diazonium salt. N₂ is a good leaving group, so, diazonium salt is allowed to warm up to give phenol substituted product.Lastly, the final product will synthesize by the addition of nitrating mixture.

Synthesis ofp-benzylchlorobenzene (c)

Benzene is substituted to chlorobenzene by halogenation using Lewis’s acid catalyst (FeCl₃).Friedel crafts acylation reaction substitutes CH₂Cl group in benzene ring and further addition of benzene results in the product, benzyl chlorobenzene.

Synthesis ofbenzyl methyl ether (d)

Synthesis of (d)

Benzene undergoesFriedel crafts alkylation reaction and gives alkylated product, which on further reaction with bromine and methoxide results in the product, benzyl methyl ether.

Synthesis ofp-nitroaniline (e)

Benzene undergoes halogenation reaction andgives bromobenzene, which on addition with nitration mixture obtains nitrated benzene compound. Amine solution is added to this compound to get the product, p-nitroaniline.

Synthesis ofm-bromoiodobenzene (f)

Addition of nitrating mixture substitute benzene with a nitro group which on halogenation, reduction reaction gives 3-bromoaniline as the product.[l1] Lastly, diazonium group will replaceiodo group.

[l1]Kindly rephrase to make the meaning clearer.

Synthesis ofp-dideuteriobenzene (g)

Benzene compound undergoes halogenation reaction two times and gives the product dibromobenzene. Then substitution of deuterium instead of MgBr[l1] gives the product dideuteriobenzene.

[l1]Why is deuterium substitutedinstead of MgBr?

Synthesis ofp-nitro-N-methylaniline (h)

In this mechanism, benzene can be converted to 1-bromo-4-nitrobenzene. Then this compound reacts with alkylamine and gives the final product, p-nitro-N-methylaniline.

Synthesis of1-bromo-3-nitrobenzene (i)

Halogenation reaction converts nitrobenzene to 1-bromo-3-nitrobenzene.