Question

What starting compound and what reagents should be used for most efficient synthesis of 2-bromo-1-iso-propyl-4-nitrobenzene? Efficient synthesis means that on each step you take the major product or one of the major products and continue reacting it with assigned reagent further. The final product is must be major product of the reaction as well.

Select one:
A. Start with iso-propylbenzene First step: HNO,+H2S04 Second step: Br2+FeBr
B. Start with bromobenzene First step: HNO,+H2SO Second step: 2-chloropropane + AIC
C. Start with nitrobenzene First step: 2-chloropropane +AICI Second step: Br,+FeBr

Answer 1

A

Step-by-step explanation:

Alkyl substituents on benzene are ortho, para directing. They activate the benzene ring towards electrophilic substitution at the 2 and 4 positions. Nitration is an electrophilic addition to the benzene ring and will occur at the 2 and 4 positions. The para nitro product predominates due to steric effects. Bromine, being smaller than -NO2 can be directed to the ortho position. Hence te compound is formed