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Which of the following is an appropriate set of reactants for the preparation of 1-methoxy-4-nitrobenzene and why?

(a) Methanol and 4-nitrophenol

(b) Methanol and 1,4-dinitrobenzene

(c) Sodium methoxide and 1,4-dinitrobenzene

(d) Methanol and p-methoxyphenol

1 Answer

2 votes

Final answer:

The correct set of reactants for the synthesis of 1-methoxy-4-nitrobenzene is methanol and 4-nitrophenol, using a Williamson ether synthesis reaction where methanol is deprotonated to form a methoxide ion that attacks the para position of 4-nitrophenol. Therefore, the correct option is A.

Step-by-step explanation:

An appropriate set of reactants for the preparation of 1-methoxy-4-nitrobenzene is (a) methanol and 4-nitrophenol. This is because a Williamson ether synthesis reaction can be used to form ether bonds by reacting an alcohol with a phenol under appropriate conditions. In this case, methanol would act as the nucleophile and 4-nitrophenol as the electrophile. The presence of a strong base would deprotonate methanol to form methoxide ion, which is a strong nucleophile and would attack the para position of 4-nitrophenol to synthesize 1-methoxy-4-nitrobenzene.

Option (b) is incorrect because there are two nitro groups present in 1,4-dinitrobenzene which would make the benzene ring too deactivated for a nucleophilic substitution to occur. Option (c) is incorrect because sodium methoxide and 1,4-dinitrobenzene would similarly struggle due to deactivation by the nitro groups. Finally, option (d) is wrong because p-methoxyphenol already has a methoxy group at the para position, which would prevent the addition of another methoxy group.

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