JEE MainChemistryHydrocarbons
Consider the following nitrogen-containing compounds: (A) Quinoline (B) 1,2,3,4-Tetrahydroisoquinoline (C) 3,4-Dihydroquinolin-2(1H)-one (D) 1,2,3,4-Tetrahydroquinoline The correct increasing order of their reactivity towards aromatic electrophilic substitution is:
Options
- AA < B < C < D
- BD < C < B < A
- CA < B < D < C
- DA < C < B < D
Correct answer
A. A < B < C < D
Step-by-step solution
The rate of electrophilic aromatic substitution (EAS) depends on the electron density of the aromatic ring. Electron-donating groups increase the rate, while electron-withdrawing groups decrease it. In (A) Quinoline, the benzene ring is fused to an electron-deficient pyridine ring, which strongly deactivates it via -I and -R effects. In (B) 1,2,3,4-Tetrahydroisoquinoline, the nitrogen atom is not directly attached to the benzene ring. The benzene ring is only attached to alkyl carbons, experiencing weak +I and +H a