JEE MainChemistryHydrocarbons
Consider the following reaction sequence: n-propylbenzene HNO ₃/ H ₂ SO ₄ P (major) NBS / Q (major) alc. KOH / R (major) The IUPAC name of the final major product R is:
Options
- A3-(4-nitrophenyl)prop-1-ene
- B1-(4-nitrophenyl)prop-1-ene
- C1-(2-nitrophenyl)prop-1-ene
- D1-(4-nitrophenyl)propan-1-ol
Correct answer
B. 1-(4-nitrophenyl)prop-1-ene
Step-by-step solution
Nitration of n-propylbenzene with HNO ₃/ H ₂ SO ₄ yields 1-propyl-4-nitrobenzene (P) as the major product due to the ortho/para directing nature of the alkyl group and steric hindrance at the ortho position. Reaction of P with NBS (N-bromosuccinimide) and heat results in free radical substitution at the benzylic position, giving 1-(1-bromopropyl)-4-nitrobenzene (Q). Treatment of Q with alcoholic KOH and heat causes dehydrohalogenation (E2 elimination). According to Zaitsev's rule, the more substituted and conjugate